Source: https://seerepo.com/compare/jj-vcs/jj/vs/openai/codex
Markdown source: https://seerepo.com/compare/jj-vcs/jj/vs/openai/codex.md
Description: jj and codex share 6 technologies: Tokio, crossterm, ansi-to-tui, Ratatui, tracing, and tracing-subscriber. Both are written in Rust.

# jj vs codex

jj and codex share 6 technologies: Tokio, crossterm, ansi-to-tui, Ratatui, tracing, and tracing-subscriber. Both are written in Rust.

- [jj-vcs/jj](https://seerepo.com/r/jj-vcs/jj): A Git-compatible VCS that is both simple and powerful
- [openai/codex](https://seerepo.com/r/openai/codex): Lightweight coding agent that runs in your terminal

## What they share and what sets them apart

- In common: Tokio, crossterm, ansi-to-tui, Ratatui, tracing, tracing-subscriber
- Only in jj: clru, sapling-renderdag, rpassword, tracing-chrome
- Only in codex: axum, codex-attachment-store, codex-cloud-tasks-client, codex-queue-extension, codex-thread-store, codex-utils-cache, sqlx-sqlite, sqlx, libsqlite3-sys, lru, SQLite, Sentry, rama-http, rama-core, tiny_http, tower, rama-http-backend, objc2-app-kit, objc2-foundation, two-face, codex-tui, ratatui-macros, sqlx-macros, codex-aws-auth, codex-keyring-store, codex-login, codex-user-verification, codex-websocket-auth, codex-workload-identity, oauth2, keyring, jsonwebtoken, ed25519-dalek, hmac, objc2-local-authentication, codex-agent-graph-store, codex-agent-identity, codex-agent-message-board-client, codex-agent-message-board-extension, codex-agent-roles, codex-chatgpt, codex-client, codex-code-mode-runtime, codex-collaboration-mode-templates, codex-context-fragments, codex-core-plugin-common, codex-extension-api, codex-external-agent-migration, codex-guardian-context, codex-guardian-reviewer, codex-image-generation-extension, codex-lmstudio, codex-mcp, codex-mcp-extension, codex-memories-extension, codex-memories-read, codex-memories-write, codex-message-board-mcp, codex-model-provider, codex-model-provider-info, codex-models-manager, codex-ollama, codex-plugin-host, codex-prompts, codex-protocol, codex-response-debug-context, codex-runtime-agent-instance, codex-skills, codex-skills-extension, codex-tools, codex-web-search-extension, openai-codex-cli-bin, rmcp, bm25, codex-mermaid, codex-utils-image, codex-utils-template, png, image, pulldown-cmark, zip, linkify, quick-xml, symphonia, schemars, Pydantic, codex-otel-trace-websocket, codex-rollout-trace, tracelogging, OpenTelemetry, tracing-opentelemetry, log, opentelemetry-otlp, tracing-appender, opentelemetry-semantic-conventions, opentelemetry-appender-tracing, opentelemetry-http

## Side by side

| | jj | codex |
|---|---|---|
| Size | 284,964 lines written, 313 code files | 2,374,591 lines written, 4,286 code files |
| Who writes it | 0.1% of its commits signed by AI. With Gemini CLI and Claude Code | 2.7% of its commits signed by AI. With Codex, Claude Code, and GitHub Copilot |
| Activity | Last push November 7, 2026, 12,142 commits, 32,392 stars | Last push November 9, 2026, 13,317 commits, 133,900 stars |
| Tests | 128 test files | 2,509 test files. 51.9% of its code files have a test that imports them |

- Size: Lines written by people and agents, without generated ones; code files, without tests.
- Who writes it: A commit counts as AI's when it carries its signature: a Co-Authored-By line, its author name or the merge of its branch.
- Activity: From GitHub and its history, on the day SeeRepo read it.
- Tests: The files that test the code, and the share of code files a test imports.

## Frequently asked questions

### Which is bigger, jj or codex?

codex, with 2,374,591 lines written; jj has 284,964.

The proof: [openai/codex's code at commit 6107b98](https://github.com/openai/codex/tree/6107b9886c114702e5c1cfd1c1b54f7c48bfaf49)

### Which has more GitHub stars, jj or codex?

codex, with 133,900 stars; jj has 32,392.

The proof: [openai/codex on GitHub](https://github.com/openai/codex)

### Which has more tests, jj or codex?

codex, with 2,509 test files; jj has 128.

The proof: [openai/codex's code at commit 6107b98](https://github.com/openai/codex/tree/6107b9886c114702e5c1cfd1c1b54f7c48bfaf49)

### Which was updated more recently, jj or codex?

codex: its last push was on November 9, 2026, and jj's on November 7, 2026.

The proof: [openai/codex's commits on GitHub](https://github.com/openai/codex/commits)

### Which has more commits signed by AI, jj or codex?

codex: an AI signed 2.7% of its commits, with Codex, Claude Code, and GitHub Copilot; in jj, 0.1%.

The proof: [the commits each tool signed in openai/codex](https://seerepo.com/r/openai/codex/ai)

## Sources

- jj-vcs/jj: Read on November 7, 2026, at commit 7fdb0d1 (https://github.com/jj-vcs/jj/tree/7fdb0d1088f3592e73e31967b21322ef2299ce85)
- openai/codex: Read on November 9, 2026, at commit 6107b98 (https://github.com/openai/codex/tree/6107b9886c114702e5c1cfd1c1b54f7c48bfaf49)

## What is your repo built with?

Any public repo, with no account: https://seerepo.com/r/owner/repo/built, with the owner and name it has on GitHub.