Source: https://seerepo.com/compare/headroomlabs-ai/headroom/vs/xerj-org/xerj
Markdown source: https://seerepo.com/compare/headroomlabs-ai/headroom/vs/xerj-org/xerj.md
Description: headroom and xerj share 11 technologies: axum, rusqlite, SQLite, Tokio, tower, hf-hub, ort, tokenizers, tracing, prometheus, and tracing-subscriber. headroom is written in Python and xerj in Rust.

# headroom vs xerj

headroom and xerj share 11 technologies: axum, rusqlite, SQLite, Tokio, tower, hf-hub, ort, tokenizers, tracing, prometheus, and tracing-subscriber. headroom is written in Python and xerj in Rust.

- [headroomlabs-ai/headroom](https://seerepo.com/r/headroomlabs-ai/headroom): Compress tool outputs, logs, files, and RAG chunks before they reach the LLM. 20% fewer tokens for coding agents, 60-95% fewer tokens for JSON, same answers. Library, proxy, MCP server.
- [xerj-org/xerj](https://seerepo.com/r/xerj-org/xerj): AI search engine and MCP server for bots and agents. One Rust binary indexes code, docs, logs, JSONL/CSV and PDFs for BM25 full-text, vector and hybrid search, code search without grep, agent memory and RAG. Elasticsearch-compatible API; Corpus Hub serves hundreds of reference memory corpora.

## What they share and what sets them apart

- In common: axum, rusqlite, SQLite, Tokio, tower, hf-hub, ort, tokenizers, tracing, prometheus, tracing-subscriber
- Only in headroom: FastAPI, Redis, lru, Rich, gcp_auth, autogen-agentchat, litellm, tiktoken, tiktoken-rs, Pydantic, OpenTelemetry, @opencode-ai/plugin, @ai-sdk/provider, ai
- Only in xerj: axum-extra, axum-server, aws-sdk-s3, webauthn-rs, hmac, argon2, candle-core, candle-nn, candle-transformers, zip, quick-xml, cfb, calamine, csv, mail-parser

## Side by side

| | headroom | xerj |
|---|---|---|
| Size | 789,601 lines written, 773 code files | 896,832 lines written, 725 code files |
| Who writes it | 28.1% of its commits signed by AI. With Claude Code, GitHub Copilot, Codex, Cursor, Devin, and Mistral Vibe | 21% of its commits signed by AI. With Claude Code, Cursor, and Codex |
| Activity | Last push November 4, 2026, 3,201 commits, 78,851 stars | Last push November 6, 2026, 2,945 commits, 19,074 stars |
| Tests | 1,220 test files. 68.2% of its code files have a test that imports them | 358 test files. 9.7% 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, headroom or xerj?

xerj, with 896,832 lines written; headroom has 789,601.

The proof: [xerj-org/xerj's code at commit 87bf7ac](https://github.com/xerj-org/xerj/tree/87bf7acf92bbeb6c25fa2ad74d082219c094e18d)

### Which has more GitHub stars, headroom or xerj?

headroom, with 78,851 stars; xerj has 19,074.

The proof: [headroomlabs-ai/headroom on GitHub](https://github.com/headroomlabs-ai/headroom)

### Which has more tests, headroom or xerj?

headroom, with 1,220 test files; xerj has 358.

The proof: [headroomlabs-ai/headroom's code at commit 31dcaf4](https://github.com/headroomlabs-ai/headroom/tree/31dcaf41f7fafaebec0838a05ff328da456faef0)

### Which was updated more recently, headroom or xerj?

xerj: its last push was on November 6, 2026, and headroom's on November 4, 2026.

The proof: [xerj-org/xerj's commits on GitHub](https://github.com/xerj-org/xerj/commits)

### Which has more commits signed by AI, headroom or xerj?

headroom: an AI signed 28.1% of its commits, with Claude Code, GitHub Copilot, Codex, Cursor, Devin, and Mistral Vibe; in xerj, 21%.

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

## Sources

- headroomlabs-ai/headroom: Read on November 4, 2026, at commit 31dcaf4 (https://github.com/headroomlabs-ai/headroom/tree/31dcaf41f7fafaebec0838a05ff328da456faef0)
- xerj-org/xerj: Read on November 6, 2026, at commit 87bf7ac (https://github.com/xerj-org/xerj/tree/87bf7acf92bbeb6c25fa2ad74d082219c094e18d)

## 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.