XERJ review

Q: How do I install XERJ?

Run curl -fsSL https://xerj.org/get | sh. The install section above has the other options from the project's README.

XERJ is a local-first search engine and MCP server for AI agents, packaged as one Rust binary with an Elasticsearch-compatible API.

Updated Nov 1, 2026. Review written Nov 1, 2026 from the project's own sources; usage data refreshed every Monday.

TL;DR

XERJ is a single Rust binary that indexes code, docs, logs, JSONL/CSV and PDFs for BM25, vector and hybrid search, code search and agent memory. It is for developers using coding agents such as Claude Code or Cursor. It focuses on reference coding: indexing related open-source repos so an agent retrieves exact passages instead of reading whole files.

17.9kGitHub stars
+2.8knew stars, week of Oct 25
#1in RAG, data and memory this week

XERJ at a glance

Category: RAG, data and memory
Maintained by: xerj-org (individual, @xerj-org on GitHub)
License: Apache 2.0
Language: Rust, HTML, JavaScript
Repository: github.com/xerj-org/xerj
Website: xerj.org
Latest release: pack-rust-vulns-2026-11-01 on GitHub, Nov 1, 2026
First published: Jun 30, 2026

What XERJ does

XERJ indexes code, docs, logs, JSONL/CSV and PDFs for BM25 full-text, vector and hybrid search.
XERJ parses source files with tree-sitter, so code is indexed with its symbols and line numbers instead of flat text.
XERJ sniffs each file in a folder and creates one index per dataset, with no schema or pipeline to configure.
XERJ answers go-to-definition queries with xerj def, returning file:line and the signature.
XERJ stores agent long-term memory under /_memory/{namespace} and recalls it by meaning in later sessions.
XERJ speaks the Elasticsearch API, so existing clients, dashboards and tooling work against it unchanged.
XERJ pulls signed, pre-indexed Corpus Hub packs, checking sha256 and an ed25519 signature before extraction.

How to install and start using XERJ

Linux and macOS

curl -fsSL https://xerj.org/get | sh

Windows PowerShell

irm https://xerj.org/get.ps1 | iex

With Nix

nix run github:xerj-org/xerj -- --version

Requirements

Linux, macOS or Windows on x86-64 or arm64. x86-64 builds need x86-64-v2 (SSE4.2).
Without --insecure, auth is on and autoindex needs --api-key or XERJ_API_KEY, read from <data_dir>/admin.key.
Neural embedding mode needs three model files staged locally before the first semantic operation. The default lexical embedder works offline.

First steps

Start a local dev node: xerj --insecure --data-dir ~/xerj-data &
Run xerj init to wire XERJ into Claude Code or Cursor through MCP and a skill.
Index a project with xerj autoindex ~/my-project.
Query it with xerj search followed by a plain-English question to get ranked passages with file:line.

Who XERJ is for

Developers whose coding agents work with private, internal, niche or post-cutoff code.
Claude Code, Cursor or other MCP client users who want agents to retrieve passages instead of grepping files.
Teams who want codebase Q&A, log analysis or security audits through an Elasticsearch-compatible API.
Agent builders who need persistent long-term memory recalled by meaning.

Limitations to know

XERJ's reference-coding benefit is neutral to harmful on popular public libraries the model already knows, according to the README.
XERJ's --insecure mode turns off TLS and API-key auth, making every caller that can reach the port a superuser.
XERJ does not discover or migrate other data directories, and a data directory inside an indexed folder gets indexed itself.
XERJ reads binary-serialized Unity assets only after Force Text is applied.

Is XERJ growing? Usage data

In the week of Oct 25–31, 2026, XERJ ranked #6 on the Devtoolwatch Board and #1 in RAG, data and memory, with a momentum score of 97 out of 100.

New GitHub stars per week for the last 12 weeks, from GitHub's stargazer history (today's stargazers by the week they starred).

Show the weekly numbers

New GitHub stars per week for XERJ
Week of	New stars
Aug 9, 2026	177
Aug 16, 2026	234
Aug 23, 2026	141
Aug 30, 2026	143
Sep 6, 2026	46
Sep 13, 2026	73
Sep 20, 2026	528
Sep 27, 2026	151
Oct 4, 2026	869
Oct 11, 2026	4.3k
Oct 18, 2026	7.5k
Oct 25, 2026	2.8k

The Board ranks tools by four signals each week: new stars, new stars for the repo's size, added downloads and download growth beyond the market. How the ranking works.

XERJ alternatives

Other RAG, data and memory tools on the Board in the week of Oct 25–31, 2026, by momentum:

RAG, data and memory ranked by momentum, the week of Oct 25–31, 2026
Rank	Tool	Stars	Downloads/wk
#2	MemvidMemvid is a single-file memory layer for AI agents that packages data, embeddings, search indexes, and metadata into one portable .mv2 file.	17.3k	–
#3	LEANNLEANN is a Python vector database and RAG library that recomputes embeddings on demand to keep indexes small on personal devices.	13.7k	–
#4	GraphifyGraphify is an AI coding assistant skill that turns a codebase, with its docs, PDFs, images and videos, into a queryable knowledge graph.	140k	480.7k
#5	MarkItDownMarkItDown is a lightweight Python utility from Microsoft that converts PDFs, Office documents, images, audio and other files to…	193.2k	4.7M
#6	FirecrawlFirecrawl is an API and open source project to search, scrape, crawl, and interact with web pages, returning LLM-ready markdown or JSON…	197.4k	2.9M
#7	Mem0Mem0 is a memory layer for AI agents and apps that stores and retrieves user, session, and agent context across interactions.	68.2k	884.1k

All RAG, data and memory tools, ranked

Recent XERJ releases

pack-rust-vulns-2026-11-01 (pre-release), Nov 1, 2026
pack-rust-vulns-d7236e78-r2 (pre-release), Nov 1, 2026
pack-agent-session-trajectories-13d0fbe1-r13 (pre-release), Nov 1, 2026
pack-agent-session-trajectories-2026-11-01 (pre-release), Nov 1, 2026
pack-mesh-patterns-1758bec8 (pre-release), Oct 31, 2026

XERJ FAQ

Is XERJ free and open source?

Yes. XERJ's source code is on GitHub (xerj-org/xerj) under the Apache 2.0 license, so you can use it for free. Its website also links to a pricing page (https://xerj.org/pricing/) for any paid plans.

How do I install XERJ?

Run curl -fsSL https://xerj.org/get | sh. The install section above has the other options from the project's README.

Is XERJ still maintained?

Yes. The xerj-org/xerj repository was last updated on Nov 1, 2026, and the latest release, pack-rust-vulns-2026-11-01 on GitHub, came out on Nov 1, 2026.

How popular is XERJ?

XERJ has 17.9k GitHub stars as of Nov 1, 2026. It gained 2.8k new stars in the week of Oct 25–31, 2026, against a 12-week average of 1.4k a week. That made it #1 among RAG, data and memory tools on the Devtoolwatch Board.

What are the best alternatives to XERJ?

Other RAG, data and memory tools on the Devtoolwatch Board in the week of Oct 25–31, 2026, by momentum: Memvid (#2), LEANN (#3), Graphify (#4), MarkItDown (#5), Firecrawl (#6). The alternatives table above has their numbers.

Which file types can XERJ index?

XERJ indexes code, CSV, JSON, JSONL, XML, YAML, SQLite, PDF, DOCX, PowerPoint, Excel, EPUB, Jupyter notebooks, man pages, HTML, mail and common log formats. Unity projects get per-GameObject records.

Does XERJ work with Claude Code and Cursor?

Yes. XERJ works with Claude Code, Cursor and any MCP client. The xerj init command wires it into Claude Code or Cursor with MCP and a skill in one step.

Can I use existing Elasticsearch clients with XERJ?

Yes. XERJ speaks the Elasticsearch API, so existing clients, dashboards and tooling work against it unchanged.

Is it safe to run XERJ with --insecure?

XERJ's --insecure mode is meant for one user on a dev machine. It disables TLS and auth. A fresh node binds 127.0.0.1 only and refuses a cleartext bind on other interfaces unless you explicitly allow it.

Can XERJ run without internet access?

Yes. The README links an air-gapped deployment recipe. The default lexical embedder is offline. Neural mode needs three model files staged locally first.

What is Corpus Hub in XERJ?

Corpus Hub serves pre-indexed, signed reference corpus packs. You pull one with a command such as xerj hub pull rust-vulns, and XERJ verifies the archive before extracting it.

Sources

XERJ README badge

Maintainers can show the tool's weekly Board rank in their README:

[![Devtoolwatch](https://index.devtoolwatch.com/badge/xerj-org-xerj.svg)](https://index.devtoolwatch.com/tools/xerj-org-xerj/)

How this page is made: Devtoolwatch writes each review from the project's README, releases, package metadata and website, with an AI model, then checks every claim against the source it cites and drops what the sources don't support. The numbers come from Devtoolwatch's daily GitHub snapshots, GitHub's stargazer history, and the npm and PyPI download APIs. Spotted an error? Email [email protected].