API interfaces

• twitter_pack - Twitter API interface.
• irc_client - Low-level IRC interface.
• geoip - GeoIP interface.
• pl_omdb - OMDB API interface.
• amazon_api - Amazon API interface.
• blog_core - Blog/CMS framework.

Artificial Intelligence

• zamia-ai - Open source AI system.

Build Systems

• biomake - GNU-Make-like building utility.

Compilers

• Eclipse CLP - A constraint logic programming system.
• Ciao - A Prolog system with many extensions.
• GNU Prolog - ISO Prolog compiler with useful extensions.
• SWI-Prolog - Widely used, comprehensive Prolog compiler.
• YAP - High-performance Prolog compiler.
• XSB - XSB logic programming and deductive database system.

Database

• prolongo - MongoDB driver.
• docstore - Document-oriented database.
• TerminuDB - for knowledge graph representation
• db_facts - Centric abstraction layer for SQL.
• bio_db - Biological datasets manager.
• prosqlite - SQLite interface.

Date

• julian - Date-time library.

Development

• condition - Common Lisp-like condition system.
• function_expansion - Function-like macros.
• typedef - Type definitions.
• lambda - Lambda expressions.
• func - Function application and composition.
• fsyntax - Ciao functional syntax.

IDE

• Prolog Development Tool - Prolog IDE for Eclipse.
• swish - SWI-Prolog web IDE.
• VSC-Prolog - Prolog extension for Visual Studio Code.

Interpreters

• golog - Interpreter in Go.
• erlog - Interpreter in Erlang.
• jiprolog - Interpreter in Java.
• prolog.js - Interpreter in JavaScript.
• prolog - Interpreter in Haskell.
• ELPI - Embeddable λProlog Interpreter in OCaml.
• scryer prolog - ISO-compatible interpreter in Rust.
• chalk - Interpreter in Rust.

JSON

• djson - Declarative JSON.

Logging

• log4p - Logging library.
• httplog - HTTP logfiles.

Machine Learning

• cplint - Reasoning suite for probabilistic logic programs.
• cplint_datasets - Dataset for machine learning.
• mlu - Probabilistic logic programs.

Math

• matrix - Matrix operations.
• nan_numerics_prime - Prime numbers library.
• pljulia - Numerical and technical computing.

Miscellaneous

• turing - Turing Machine simulator.
• yesbot - IRC Bot.
• Online compiler - Execute Prolog online.
• webconsole - Browser as HTML console.
• prologmud - Online text adventure game.

Native

• inotify - Linux notification library.
• plmidi - Macos MIDI interface.
• by_unix - Unix primitives library.
• plgi - Gnome bindings.

Object Oriented Programming

• logtalk - Object oriented logic programming.

Parsing

• atom_feed - Atom and RSS feeds parser.
• markdown - Markdown parser.
• yaml - YAML parser.
• tokenize - Straightforward text tokenizing.

Regular Expressions

• regex - Regular expressions library.

Resources

Books

• Coding Guidelines for Prolog - Coding standards and good practices for Prolog.
• Logic, Programming and Prolog - Foundations of Logic programming and programming techniques in Prolog.
• Adventure in Prolog - Pragmatic approach to Prolog.
• Building Expert Systems in Prolog - Build prototype expert system shells and their underlying inference engines.
• The Art of Prolog - Advanced programming techniques for Prolog.
• Prolog Programming in Depth - Full coverage of the Prolog programming language.
• Artificial Intelligence through Prolog - In-depth coverage of key concepts on artificial intelligence.

Community

• SWI-Prolog Discourse - Official SWI-Prolog Discourse board.
• Stack Overflow Prolog - User questions under the Prolog tag.
• Reddit Prolog - Logic Programming and Prolog subreddit.
• Prolog FAQ - Frequently Asked Questions list of the SWI-Prolog newsgroup.
• SWI-Prolog Mailing List - Announcements, questions and discussion among SWI-Prolog users.

Free Courses

• Prolog Online Training - Tutorials Point's series on Prolog.
• Prolog in Artificial Intelligence - Tutorials Point's series on Prolog with lectures relating Prolog to AI.

Tutorials

• The Power of Prolog - Introduction to modern Prolog.
• Prolog Wikibook - Thorough Prolog overview.
• Prolog for Software Engineering - Software engineering fundamentals using Prolog.
• Web Applications in SWI-Prolog - Building web application with SWI-Prolog.
• Printing Messages in SWI-Prolog - IO handling in libraries.
• Prolog Modules - Fundamentals in SWI-Prolog Modules.
• Constraint Logic Programming over Finite Domains - Fundamentals of Constraint Systems on Finite Domains.
• Learn Prolog Now! - Thorough introductory course to programming in Prolog.
• P-99: Ninety-Nine Prolog Problems - Practice problems in Prolog and Logic programming.
• Simply Logical - Intelligent reasoning by example.

Videos

• Prolog Tutorial - General hour-long video tutorial.
• Introduction to Prolog - Hour-long introduction to Prolog.
• Programming In Prolog - Four-part video introduction.

REST Frameworks

• arouter - HTTP router/dispatcher.

Server

• httppl - Simple HTTP server.
• letswicrypt - HTTPS server.

Testing

• tap - Automated TAP testing.
• quickcheck - QuickCheck randomized testing.
• PlUnit - Prolog unit tests.

Text Editor Extensions

• prolog.vim - Prolog integration for Vim.
• ediprolog - Prolog integration for Emacs.
• sublimeprolog - Prolog integration
• repl.vim - VIM REPL with support for SWIProlog.
• Ciao mode for Emacs - Emacs mode for Ciao and Prolog.

Utilities

• list_util - List utility predicates.
• cplint_r - R plotting predicates.
• tuProlog - Light-weight system for distributed applications and infrastructures.
• pac - Anonymous predicates expansion utility.
• gvterm - Reveal terms using Graphviz.
• odf_sheet - Load and analyze ODF spreadsheets.
• graphml - Create GraphML files.
• fileutils - File manipulation library.
• dia - UML loading predicates.