Best Open Source Alternatives to Codex

Compare the best free and open-source alternatives to Codex — self-hosted and desktop replacements you fully control, ranked by GitHub stars, license and platform support.

Curated by open-source.store · Updated November 2026 · 13 alternatives

Codex

Proprietary SaaS

Codex alternatives compared

Open-source alternatives to Codex, compared by stars, license and platform
Tool		License	Platforms	Self-hosted
pi	119,790	MIT	DockerLinux	Yes	Nov 2026	Visit
OpenHands	92,578	MIT	DockerLinux	Yes	Nov 2026	Visit
Cline	71,255	Apache-2.0	Web	No	Nov 2026	Visit
Aider	49,922	Apache-2.0		No	May 2026	Visit
T3 Code	43,616	MIT	LinuxmacOSWindows	No	Nov 2026	Visit
Kilo	27,849	MIT		No	Nov 2026	Visit
Grok Build	27,669	Apache-2.0	Web	No	Sep 2026	Visit
Plandex	15,893	MIT		No	Oct 2025	Visit
Forgecode	7,634	Apache-2.0		No	Nov 2026	Visit
Emdash	6,174	Apache-2.0	LinuxmacOSWindows	No	Nov 2026	Visit

Top open-source Codex alternatives

pi119,790MIT

Open-source terminal coding agent alternative to Claude Code with multi-provider LLM support, tree session history, and zero subscription markups.

DockerLinux

vs Codex: a free, open-source option you fully control, licensed MIT.

Visit Details

OpenHands92,578MIT

OpenHands is a self-hosted open-source alternative to Devin that runs autonomous coding agents and automations across local and cloud Docker runtimes.

DockerLinux

vs Codex: a free, open-source option you fully control, licensed MIT.

Visit Details

Cline71,255Apache-2.0

Cline is an open-source autonomous coding agent that replaces flat-rate AI subscriptions with direct pay-per-token model routing in your IDE and CLI.

Web

vs Codex: a free, open-source option you fully control, licensed Apache-2.0.

Visit Details

Aider49,922Apache-2.0

Aider is a free open-source CLI for AI pair programming in your terminal. Edits code across files, commits to git, and works with any LLM via API.

vs Codex: a free, open-source option you fully control, licensed Apache-2.0.

Visit Details

T3 Code43,616MIT

T3 Code is an open-source GUI for coding agents like Claude Code and Codex, providing Git worktree isolation and visual diff reviews without token markups.

LinuxmacOSWindows

vs Codex: a free, open-source option you fully control, licensed MIT.

Visit Details

Best Open Source Alternatives to Codex

Codex

Codex alternatives compared

Top open-source Codex alternatives

The modern standard for Protobuf workflows

Mentoring for backend developers. Consulting for startups.

More alternatives to Codex

Kilo

Grok Build

Plandex

Forgecode

Emdash

Synara

PearAI

Cody