Best Documentation Open Source Tools in 2026

PDF4QT

IT Management Business & Productivity Design & Creative

Open source PDF editor and viewer for Windows and Linux

stars 1.3Klicense MITlang C++

Developer Tools Coding Open Core+5

BLOOM

AI & Machine Learning

Open weights, GPT-3 scale, support for 46 natural languages

stars 1Klicense NOASSERTIONlang Shell

LLM AI Coding Assistant Coding+3

Zettlr

Business & Productivity Communication & Collaboration Product & Project Management

Open source Markdown editor for researchers and academics

stars 12.9Klicense GPL-3.0lang TypeScript

Knowledge Management Note-taking Apps Documentation+5

MyPaint

Design & Creative

Free open source painting app optimized for drawing tablets

stars 2.9Klicense GPL-2.0lang Python

Graphic Design Open Core UI/UX Design+1

Converse.js

Communication & Collaboration Web & App Development

Self-hosted web-based XMPP chat client for any server

stars 3.2Klicense MPL-2.0lang JavaScript

Chat WebSocket Servers Self Hosted+10

Scoold

Communication & Collaboration Business & Productivity IT Management+2

Self-hosted Q&A platform for internal team knowledge

stars 916license Apache-2.0lang Java

Knowledge Management Knowledge Base Customer Support+11

Apache PDFBox

Web & App Development Product & Project Management

Open source Java library for creating and parsing PDFs

stars 3Klicense Apache-2.0lang Java

Developer Tools Coding Documentation+3

SigNoz

Security & Monitoring Product & Project Management Data & Analytics+2

Open source APM with logs, traces, metrics, and dashboards

stars 26.7Klicense NOASSERTIONlang TypeScript

Monitoring Self Hosted Open Core+19

Huly

Product & Project Management Communication & Collaboration Business & Productivity

One open source workspace to replace Jira, Slack, and Notion

stars 25.5Klicense EPL-2.0lang TypeScript

Project Management Knowledge Management File Sharing+5

pdftk-java

Web & App Development

Java port of PDFtk for merging, splitting, and stamping PDFs

stars 2.2Klicense NOASSERTIONlang HTML

Developer Tools Coding AI Coding Assistant+2

Ghostscript

Web & App Development IT Management

Open source PDF and PostScript interpreter and converter

stars 224license NOASSERTIONlang C

Developer Tools API Development Tools Coding+4

Typesense

Web & App Development AI & Machine Learning Data & Analytics+1

Fast typo-tolerant search engine with instant results

stars 555license Apache-2.0lang TypeScript

Search Engine Open Core Developer Tools+12

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PDF4QT

BLOOM

Zettlr

MyPaint

Converse.js

Scoold

Apache PDFBox

SigNoz

Huly

pdftk-java

Ghostscript

Typesense

PDF4QT

BLOOM

Zettlr

MyPaint

Converse.js

Scoold