• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• Business Model Patterns - A list of 11 different ways to sell products and services.
• Axial - Business models - 38 models for inspiration.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• Don't just roll the dice – Software pricing guide - Not only huge and complete collection of pricing scheme, but also the psychological effect and impact on revenue model.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.
• The Network Monetization Map: Aligning Incentives with Revenue - 6 models of monetization relying on network effect.

Subscription Plans

• `f-license` - Open-source license key generation and verification tool in Go.

Usage-based Pricing

• Why I Love Usage-Based Pricing - “The most important reason I like this pricing model is that it heavily incentivizes both the customer and the service provider to act in everyone's best interest.” Also details issues with other pricing models.
• source - Or why you're likely to get an endless stream of complaining users if choosing utility pricing scheme: while accurate to the (milli-)cent, this model is frustrating for customers not ready to invest time grasping the underlaying concepts.
• Riemann sum - The starting point about quantization of usage.
• Allen's interval algebra - Implementing usage-based pricing is tricky, and this algebra will help you organize temporal reasoning. Also see this [Stack Overflow question with clean schema](https://stackoverflow.com/questions/12069082/allens-interval-algebra-operations-in-sql?rq=1).
• “Designing billing for a service can be really challenging” - Personal anecdote on the design of the pricing plan for AWS Simple Email Service.
• Electropedia: Tariffs for electricity - Before the cloud, there was another metered resource priced by its usage: electricity. Here is a detailed (and multi-lingual) taxanomy of its vocabularity from the International Electrotechnical Commission.
• Subscription-based pricing is dead: Smart SaaS companies are shifting to usage-based models - Usage-based pricing is more optimal and more fair: it “allows a customer to start at a low cost, minimizing friction to getting started while still preserving the ability to monetize a customer over time”.
• Socially Optimal Pricing of Cloud Computing Resources - “The socially optimal operating point is unique, and can be sustained by a linear, usage-based tariff, which charges a fixed price per unit resource and unit time.” This paper justify usage-based pricing for cloud resources.

Hybrid

• The Three Part Tariff - Beyond linear pricing, there is a place for an additional platform fee and free-tier component in the pricing structure.
• Google Ads API: `BillingCap` enum - Capped actuals: monthly with rollover, an optimized pricing scheme to limit surprises from customers, in which we more or less sell quotas.

Strategy

• Jim Barksdale
• The 7 factors to consider when pricing your startup product - Pricing is an offensive tool to reinforce your product value and underscore the company core marketing message.
• The cup-of-coffee pricing fallacy - Explains why it is a sloppy analogy.

Market Research

• Gabor–Granger method - Used in surveys to determine the price for a new product or service. The results can be used to produce a demand chart and a revenue curve.
• Van Westendorp's Price Sensitivity Meter - PSM is a market technique for determining consumer price preferences. Allows for drawing a revenue curve to estimate the price point delivering the maximum revenue.
• Personalised pricing and EU law - Some cases of price personalisation are prohibited in EU due to consumer protection and data protection rules.
• Jeremy Howard - From Predictive Modelling to Optimization - “In insurance, the price is the product. (…) How do I change price to make shitload of money?” Or how to deliver results (optimal price for a customer) instead of delivering data (calculating a customer's risk, which had been the standard approach used by actuaries previously).
• Pricing niche products - “The most compelling argument against simply picking a price, though, is that it limits how much you can learn about your market.” Then the author setup vickrey auction to discover price.
• Finding the max revenue price mark for digital products - “To find the optimal price that provides maximum revenue for your product you will need to field-test several price points; you then reconstruct the revenue curve and find the peak.”

Market Research

• Akeneo PIM - The open-source variant of the commercial Akeneo products.
• Pimcore - An open-source UI and database to manage product metadata, written in PHP Symfony.
• Product Data Management
• Comparing 3 open source PIM solutions - Comparative study of the 3 projects above.
• OpenPIM - A streamlined open-source project, focusing on PIM-only features.
• GCP Product Catalog - All GCP SKUs available as an API.

Market Research

• Cloud Cost Calculator - Web-based tool for finding the cheapest cloud servers for a given set of requirements.
• Cloudorado - A comparison matrix which use ECU (Amazon's vCPU) as a CPU power measure unit.

Cloud Resources

• AutoSpotting - Tool that easily and reliably converts (all) your existing AutoScaling groups to cheaper spot instances.
• source - Simple explanation of the bidding mechanism.
• source - Users are seeking more transparency on the spot market.
• The Eternal Cost Savings Of Netflix's Internal Spot Market - When you're big enough that [creating an internal secondary market](https://medium.com/netflix-techblog/creating-your-own-ec2-spot-market-6dd001875f5) for instances makes economic sense.
• Incentive Engineering for Computational Resource Management - Paper exploring the “mechanisms for the allocation of processor time and storage that are compatible both with programming practice and with market mechanisms.”
• Pricing of Service in Clouds: Optimal Response and Strategic Interactions - “How should the consumer modulate its demand to optimize its profits? (…) How should the provider and consumer negotiate the specific pricing structure they will employ?” Covers non-linear models, tiered pricing, elastic demand, consumer et provider strategies.
• Dynamic Cloud Pricing for Revenue Maximization - “Amazon's spot price is unlikely to be set according to market supply and demand. Rather, price oscillates within a very narrow band most of the time, which is more likely to be an artifact of some pricing algorithm with predetermined reserve price.”
• GCP Preemptible VMs vs AWS Spot Instances - “Google's prices are fixed, whereas AWS uses a market model”.
• Usage Patterns and the Economics of the Public Cloud - “We examine the economics of demand and supply in cloud computing. (…) These results explain why fixed prices currently prevail despite the seeming need for time-varying dynamics. Examining the actual CPU utilization provides a lens into the future. (…) demand fluctuations would be on par with the three classic industries where dynamic pricing is important (hotels, electricity, airlines) and dynamic prices would be essential for efficiency.”
• Maximizing Profit of Cloud Brokers under Quantized Billing Cycles: a Dynamic Pricing Strategy based on Ski-Rental Problem - “The key idea of our algorithms is to use pricing signal to regulate user demand. One may argue that such an algorithm gives poor service to the user as it pushes tasks out of the queue in order to maximize cloud broker's profit.”
• Present or Future: Optimal Pricing for Spot Instances - “Pricing policy of spot resources should be carefully designed and the impact on both present and future should be considered.”

Online Ads

• RTB Budget Pacing Summarized - A collection of budget pacing resources for targeted online advertisements.
• Samsung's online ads platform/exchange war story - How to scale to 5M bid request/s, 2ms Max Response Time.
• `RTB4Free` - Open Source Bidder and Demand Side Platform (DSP).

Market Research

• Customized Regression Model for Airbnb Dynamic Pricing - This paper describes the pricing strategy model deployed at Airbnb.
• 19 Tactics to Solve the Chicken-or-Egg Problem and Grow Your Marketplace - “Which comes first, the supply or the demand? Chicken or egg?”
• Papers we love: Auctions and Bidding - A collection of papers on bidding and auctions.
• Vickrey auction - Hinted by an [HN comment](https://news.ycombinator.com/item?id=19145391), in which yes, “‘Asking people what they'd pay for and how much rarely works.’ (…) \[but\] using a Vickrey auction, similar to Google's ad auction mechanism, can elicit a person's maximum willingness-to-pay.”
• Constrain the marketplace - parts series with dozen of interviews of people with direct experience building and scaling marketplaces.

Bookkeeping

• Frappe Books - Free Desktop book-keeping software for small-businesses and freelancers.
• Luca - YAML accounting and JSON tax forms.
• Sequence - API that store, validate and reports asset movements. Also known as a Ledger. Sequence is immutable, scalable, and easy to use.
• Go DB Ledger - An open source accounting system that aims to make the recording of double entry bookkeeping transactions programmable.
• Ledger - A scriptable financial ledger, designed to make it easy to model complex financial transactions.
• Akaunting - Open source software designed for small businesses and freelancers.
• So, you want to learn Bookkeeping! - Focus on the daily operations of recording and maintaining the transactions of a business.
• Plain text accounting tools - Extensive list of open-source personal finance projects that might be great to look into for inspiration on double-entry accounting and bookkeeping.
• GnuCash Tutorial and Concepts Guide - A complete tutorial on personal finance tracking with GnuCash.
• GNUCash - iii.org) (PHP).

Software design and implementation

• Managed accounts for Django - A 'managed account' is an allocation of money that can be debited and credited.
• Moonpig: a billing system that doesn't suck - Design decisions behind a billing and accounting system. Key takeaway: some companies still pays by checks; do not use floats; complex customer workflows; date and time issues; mutable data.
• Books, an immutable double-entry accounting database service - Explain the basic data model of a double-entry accounting system relying on Google Spanner for internal use at Square.
• Triple‐entry accounting with blockchain: How far have we come? - “Triple‐entry accounting is a new and a more efficient way to address fundamental trust and transparency issues that plague current accounting systems. Triple‐entry accounting with blockchain, when properly implemented, can fundamentally improve accounting.”

Online Ads

• source

Double-Entry Model

• Accounting for Computer Scientists - Describes how to view accounting in the form of graphs in which money flows, then how these movements are materialized in the financial statements of a small company.
• The Double-Entry Counting Method - Same premise as above, but way more detailed and complete, as it adds reporting and implementation details.
• Accounting Memento For Entrepreneurs (US GAAP) - An interactive form to play with accounting concepts.

Currencies

• Tutorial on multiple currency accounting - An excellent resource for implementing multi-currency accounting systems.

Currencies

• {Digital,Cloud,Electronic,Online} Services VAT Rate Database - Centralize applicable VAT rates on foreign online services, for each country of residence (including territorial exceptions).
• 2017 Tax Software Developer's Guides - A list of test cases for developers to test their tax code against.
• Global VAT & GST on digital services - List of countries requiring application of taxes on foreign provided online services.
• source - Which allows them to [claim the VAT on processing fees as input tax](https://www.gov.uk/guidance/vat-guide-notice-700#section4).
• Streamlined Sales Tax Governing Board - A multi-states US initiative to automate and standadize sales tax accounting and collection.

European VAT

• How to correctly setup SaaS subscriptions to charge VAT in Europe - “If you think you can just setup a simple Stripe integration and move on, like us, you'd be sadly mistaken.”
• What does the "Reverse Charge" refer to? - Answer: a provision in which a business transfer the responsibility of VAT handling to the customer.

European VAT

• Manta - Flexible invoicing desktop app with beautiful & customizable templates.
• InvoicePlane - A self-hosted open-source application for managing your invoices, clients and payments.
• Volcano - Flexible, gateway-agnostic billing system.
• InvoiceGenerator - Library to generate a simple invoices.
• Ruby Invoicing Framework - For generating and displaying invoices (ideal for commercial Rails apps). It allows for flexible business logic; provides tools for tax handling, commission calculation etc.
• InvoiceNet - Deep neural network to extract intelligent information from invoice documents.
• Factur-X - Python library to support the e-invoicing standard for France and Germany.
• On GCP invoiced billing - [Invoiced billing](https://cloud.google.com/billing/docs/how-to/invoiced-billing) (B2B-friendly payment by the customer after the service is consumed and an invoice issued) is a pain on GCP.
• Digital signatures: how Sleek leverages Cloud HSM to guarantee the integrity of legal documents - Here is a great way to rely on GCP's HSM to digitally sign documents and provide an immutable audit-trail. Might be applied to invoices as well as contract agreements.
• Refact - A design project trying to revamp a phone bill with infographics.
• Universal Business Language - Most invoicing software can read and write UBL documents (XML) for data transfer.
• EU eInvoicing - European standard on electronic invoice.
• Refact - A design project trying to revamp a phone bill with infographics.

Customer Lifetime Value

• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• How to project customer retention - A seminal paper, with a stronger approach compared to the one above: [the exponential distributions is replaced by a geometric model](https://news.ycombinator.com/item?id=24833319), better suited to monthly contracts.
• RFM (customer value) - A refined model of CLV, used to segment users based on Recency, Frequency and Monetary value.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• You're all calculating churn rates wrong - “On the surface, churn rate may seem like a natural proxy for changes in customer lifetimes. Let's dig into why that is not true.” Churn rate is not a meaningful metric to compute CLV, as during the customer lifetime the churn probability is not constant. Most of the time because of your free trial and vouchers.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.
• Churn Prediction - “How to use Python in a simplistic way to fuel your company's growth by applying the predictive approach to all your actions.” Relies on XGBoost binary classification.

Data Engineering

• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• Ten Ways Your Data Project is Going to Fail - You don't need data scientists. “For ETL, hire data engineers. For reporting, hire BI analysts. The end.”
• Cargo cult data science - “Data science is best viewed as a form of company culture, rather than a set of technologies. However, many firms will try to create that company culture by acquiring data-science technology, rather than working on their culture.”
• Why not use Double or Float to represent currency? - Because of precision: floats and doubles cannot accurately represent the base 10 multiples that we use for money.
• European Spreadsheet Risks Interest Group - Horror Stories - A collection of cases in which uncontrolled and untested spreadsheet models led to lost revenue, mispricing, poor decision making, fraud and systemic financial failure.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• Never Use Floats for Money - “This is precisely the problem we have when trying to represent 10^-1, or 0.1 in binary. There is not an exact binary representation of 0.1 or 0.01.”
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.
• AI vs Data Science vs Data Engineering - “Data Engineers build data pipelines and infrastructure to ensure a constant availability of transformed data. Data Scientists analyze and build models from these data to develop new product features or drive the bottom line of the business.” As for AI professionals, their focus is on cognitive automation.

Metrics

• A Quantitative Approach to Product Market Fit - Metrics produced above have a greater reach, as they're used as important signals to validate product-market fit.
• The SaaS Financial Model You'll Actually Use - A complete tour of the financials of a statup, which gives you extra-context on how the metrics you produce fit into the larger picture.

Market Research

• Transforming Financial Forecasting with Data Science and Machine Learning at Uber - Discusses how Uber apply data science and machine learning in their financial planning platforms.
• Time Series Prediction - A short introduction for pragmatists - [Facebook's Prophet](https://facebook.github.io/prophet/) (which [uses Stan underneath](https://statmodeling.stat.columbia.edu/2017/03/01/facebooks-prophet-uses-stan/)), seems to be worth checking to implement a cost forecast tool while taking care of seasonality.
• GCP Cost Forecast - An example of consumption trend line for resource consumption.
• AWS Forecast - A full-featured hosted product to perform forecasting on any time-series.
• Forecasting with sktime - A tutorial on how to use past data to make temporal forward predictions. And read the [difference between sktime and the Prophet project](https://news.ycombinator.com/item?id=24543861) mentionned above.
• Forecasting: Principles and Practice - “Comprehensive introduction to forecasting methods and to present enough information about each method for readers to be able to use them sensibly.”
• How to save money on your AWS bill - “The biggest cost savings there are: 1. Turning things off that you're not using; 2. Then spot instances; 3. Then reserved instances.”
• Komiser - Open-source tool to stay under budget by uncovering hidden costs, monitoring increases in spend, and making impactful changes based on custom recommendations.

Currencies

• Accounts Demystified: The Astonishingly Simple Guide To Accounting - Helps you learn how to analyse and monitor your company's financial performance.
• Financial Intelligence for Entrepreneurs: What You Really Need to Know About the Numbers - Allows you to fully understand how to use financial data to make better decisions for your business.
• What is FinOps - A framework for tech finance and business leadership teams to share the same language and processes of cloud operations and management.
• Algebraic Models for Accounting Systems - Advanced abstract algebra applied to the analysis of accounting systems.

Currencies

• Is this what Enterprise mean? - A use-case of badly designed contract management alienating big enterprise customers. See the [associated HN comments](https://news.ycombinator.com/item?id=27053246) on bulk license purchase.
• CUDs vs. Commit Contracts vs. SUDs in Google Cloud - Explain the differences between various types of discounts and commits in GCP.
• Quantity discounts on a virtual good: The results of a massive pricing experiment - “Implementing price reductions ranging from 9–70% for large purchases, we found remarkably little impact on revenue, either positively or negatively.”
• CUDs vs. Commit Contracts vs. SUDs in Google Cloud - Explain the differences between various types of discounts and commits in GCP.

Currencies

• Raising Prices is Hard - Backblaze post-mortem on raising prices on their main offer. They wanted to create an extension program based on credit system. This became a full-time job for a handful of their most senior engineers, and resulted in a six month project.
• Hacking Scooters: How I Created \$100k Worth Of Free Rides - A cautionary tale on how promo codes can be exploited to get unlimited free rides.
• China's Pinduoduo reports theft of online discount vouchers to police - The next level of fraud: “an online collective exploited a loophole on its platform to ‘steal’ tens of millions of yuan worth of discount vouchers”.
• The coupon code is a slap in the face - Point the negative consequences of users encountering a blank coupon field without having a coupon. See the update at the end of the article with research backing up this anecdote.

European VAT

• The Best Payment Gateway for Startups - A benchmark of top payment providers, their pricing and models.
• Avoiding Double Payments in a Distributed Payments System - RDBMS were build for banks around transactions to solve that specific issue. Then NoSQL came forcing us to carefully implement systems to avoid double spending.
• Monzo's bank transfers post-mortem - Or why you should be prepared for and work around gateway provider's outages.
• How to Build an Insurance Company - The importance of payment ops architecture.
• EU's Late Payment Directive - European rules on applicable fees for late payments.
• High failure rate of Point Of Sale devices in the upper Midwest - The root cause? People wearing a lot of wool in low humidity air, generating a lot of static.
• part 1 - ach-works-a-developer-perspective-part-2/), [part 3](https://engineering.gusto.com/how-ach-works-a-developer-perspective-part-3/), [part 4](https://engineering.gusto.com/how-ach-works-a-developer-perspective-part-4/).
• moov - Open-source infrastructure for financial technology.
• Fintech Open Source Foundation - Another set of open-source projects for financial projects.

Receipt

• The humble receipt gets a brilliant redesign - When a Netflix data engineer revisit receipts.
• The long, long history of long, long CVS receipts - “CVS is a drugstore much like other drugstores, with one important difference: The receipts are very long.”

Credit Cards

• 'Is that even legal?': Companies may be sharing new credit or debit card information without you knowing - Some credit and debit card companies have "updating service" that allows new account numbers and expiry dates to be shared with merchants. Visa's implementation is called [VAU](https://developer.visa.com/capabilities/vau) and Mastercard's is [ABU](https://developer.mastercard.com/product/automatic-billing-updater).
• Address Verification System - A system checking the matching of customer's billing addresses with the one associated with the credit card.
• pci-blackbox - PCI-DSS compliant card system built on PostgreSQL and PL/pgSQL.

Bank Accounts

• A (shallow) dive into the American banking system - Collection of miscellaneous notes primarily focused on the common cases of routable accounts, i.e. checking and savings.
• Swift Codes - Swift / BIC codes for personal use only.

Online Payments

• The untold story of Stripe - In which we learn that “once turnover hit a certain level, Paypal automatically put the business on a 21 to 60 day rolling reserve, meaning that up to 30 per cent of a company's revenue could be locked up for up to two months.”
• Optimizing payments with machine learning - Describes a classic payment workflow, then how machine learning can replace hard-coded business rules and fine-tune the payment failures/retries loop to increase the success rates of charges.

Online Payments

• Detecting fraudulent activity in a cloud using privacy-friendly data aggregates - Discusses a method to detect fraudulent activity (launching DDoS attacks, Bitcoin mining, …) by using non-intrusive, privacy-friendly data: billing data.
• Awesome List of IAM: Fraud links - Section dedicated to fraud management related to user accounts, from our sister repository.
• Driving Global Fraud Losses Down While Empowering Business Growth - In this talk by Uber Eats, we learn from the biggest payment processor that “growing businesses with declining loss rates is extremely rare in the industry”. Also, fraud can takes several forms: chargebacks on non-perishable goods, promo abuse, refunds…

Cards

• How I Stopped a Credit Card Thief From Ripping Off 3,537 People – and Saved Our Nonprofit in the Process - Describe a fraud technique known as "card testing", in which massive batch of stolen cards are checked for their validity against your API.
• How Candy Japan got credit card fraud somewhat under control - Suggestions involved either [warning signals](https://www.candyjapan.com/behind-the-scenes/fraudulent-transaction-warning-signs) for trying to guess which orders might be fraud, or countermeasures to try to make things harder for the fraudsters.
• Training an ML model to score chargebacks - An example of a platform's network effect, which allows to predict the likelyhood of winning a dispute.
• Five Fun Fraud Facts - Another tiny collection of features we can feed to a ML system to detect fraud. Comments on HN also unearthed [more qualifying signals](https://news.ycombinator.com/item?id=6376350) and [derived geodata on the transaction](https://news.ycombinator.com/item?id=6376221).

Trust Score

• The Secret Trust Scores Companies Use to Judge Us All - Nearly everything we buy, how we buy, and where we're buying from is secretly fed into AI-powered verification services that help companies guard against credit-card and other forms of fraud.
• GCP improved account management policies to better support customers - Or why relying too much on fraud automation might lead to disgruntled users.
• Awesome Credit Modeling - How to use statistical methods to classify applicants into categories to reduce risks. Lots of inspiration and reasearch papers there to improve general scoring.

Statistics

• Benford's law - Digit distribution can be a signal of accounting fraud.
• Integer percentages as electoral falsification fingerprints - In the same spirit as above, this paper show that frequency of reported round numbers in election is a signal of man-made anomalies. Might be applicable in some fraud-fighting area.
• Huber loss - “A loss function used in robust regression, that is less sensitive to outliers in data than the squared error loss.”
• Peak Detection in the Python World - Simple way to detect outliers.

Billing

• More than 600 million users installed Android 'fleeceware' apps from the Play Store - A new kind of fraud, in which apps silently keep charging users after the end of the trial period.
• CEO Fraud - A billing team responsible for collecting payment is prey to this kind of fraud, in which the CEO is impersonated to commend exceptional payment transactions.
• The Challenges of Operating a Computing Cloud and Charging for its Use - Skip the first 90% of this presentation by an AWS VP (which is about general system reliability). The last four slides are a good summary of what billing cloud services entails, especially the use of soft quotas to limit fraud.

Tools

• AWS Cost Management announcements - The source of all new features added to the billing perimeter.
• AWS reserved instances vs saving plan - A feature matrix of the different scheme and their average dicounts.
• GCP billing release notes - Latest changes of GCP billing features.
• GCP billing news - From the unofficial Google Cloud Platform newsletter.
• More choice, less complexity: New Compute Engine pricing options on tap - A wrap-up of recent GCP pricing features.

Tools

• Orbitera - GCP's billing subsidiary.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.
• OpenCell - Monetization platform originating from an open-source telco billing project.
• ASP.NET Zero - Multi-tenancy, authentication and authorization, invoices and payments.
• Armatic Billing & Invoicing Software - Invoices, accounts receivable.
• Sensus Billing Access Application - Billing and metering solutions for utility companies.
• Quaderno - Calculate sales tax, VAT, and GST; automate receipts.
• keygen - Sell and manage license keys.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.
• 16 Online Subscription Billing Tools - An up-to-date list of subscription and recurring billing services.

Tools

• The vanished grandeur of accounting - Accounting paintings were a significant genre in Dutch art.
• Engineering and Operations in the Bell System - Starting at page #445, the "10.5 Billing Equipment and Systems" section describe the history and technical evolutions of Bell's phone calls metering and pricing.

Tools

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