Aider

An Apache-2.0 Python CLI that edits files in an existing repository, writes a commit message for each change, and feeds test and lint output back to the model. The project also maintains the code-editing benchmark it is measured on, and states that aider writes about 70–80% of its own new code.

Who built itPaul Gauthier came to aider from search infrastructure: his PhD research at UC Berkeley on computer clustering turned into Inktomi, and he was later CTO of Groupon and VP of engineering at Geomagical Labs, which IKEA acquired in 2021 — Dalhousie University, his alma mater, names him founder and CEO of Aider AI. The repository has 182 contributors, but the account `paul-gauthier` made both the first commit in May 2023 and the most recent one in May 2026, and the project maintains the code-editing benchmark and leaderboard it is measured on.

1. 01

   A repository on 2023-05-09, a first release three weeks later

   The repository was created on 2023-05-09 and the first commit landed the same day with the message `updated readme`, on the account `paul-gauthier`. On 2023-05-11 that account posted “Show HN: Aider, a command line GPT coding copilot” to Hacker News, where it scored 3 points. The first tagged release, v0.5.0, is dated 2023-06-07; the most recent, v0.86.0, is dated 2025-08-09 and was the last of 93 releases as of 2026-09-27.

2. 02

   Git as the undo button, and a map of the whole repository

   The tool runs inside an existing codebase rather than beside it: the user talks to it in the terminal, it writes to local files, and it commits each change with a generated message, so `git diff`, `git revert` and `git reset` work as undo. A repository map condenses the structure of a large project into something the model can navigate to find the file it needs. After each edit it runs the linter and the tests and returns the errors to the model to fix.

3. 03

   A benchmark the project maintains and publishes

   Aider keeps its own code-editing benchmark and LLM leaderboard and publishes the results as a public ranking. On 2024-03-27 Hacker News carried “Claude 3 beats GPT-4 on Aider’s code editing benchmark” (202 points, 228 comments), and on 2024-04-10 “Aider: AI pair programming in your terminal” (432 points, 156 comments). A 2024-05-13 discussion was titled “GPT-4o takes #1 and #2 on the Aider LLM leaderboards”.

4. 04

   Measuring how much of aider is written by aider

   A project blog post published on 2024-05-24 was titled “Aider has written 7% of its own code”; the same page now carries an update saying that figure is out of date and the current one is about 70%. The release-history page gives a range of 70–80% of the new code in each release, and states the repository’s own git history as the basis for the number. The front page displays “Singularity 88%”, and states 6.8M installs and 15B tokens per week.

5. 05

   From a personal account to an organisation

   The 2023 Hacker News post pointed at `github.com/paul-gauthier/aider`; that address now returns a 301 redirect to `github.com/Aider-AI/aider`, repository id 638629097. The project sits in the Aider-AI organisation, whose profile names it “Aider AI”. As of 2026-09-27 the GitHub API reports 49,218 stars, 5,001 forks, 1,903 open issues and 182 contributors.

6. 06

   No commits since 2026-05-22

   The most recent commit is dated 2026-05-22 and merges PR #5173, an update to the model list; as of 2026-09-27 the repository had gone 128 days without a commit. The most recent release is still v0.86.0 from 2025-08-09, more than a year before that snapshot, and 93 releases were published between 2023-06-07 and that date. The repository is not archived.