Aider vs Windsurf
Terminal pair programmer vs agent-first editor, now under a new name: Windsurf's product pages now redirect to Devin (Devin Desktop). Aider is free open-source software (Apache License 2.0); you pay your model provider or run local models, so there is no universal monthly figure. Devin offers a Free tier ($0, light agent quota, unlimited Tab completions) and Pro at $20 per month (page amounts do not label currency; verify checkout), with extra usage at API pricing. Pick Aider if you live in the terminal and want model choice with Git-native commits; pick Devin if you want a GUI editor with agent workflows. No measured quality winner.
| Decision point | Aider | Devin Desktop (formerly Windsurf) |
|---|---|---|
| Best suited to | Developers who work in a local Git repository and want an LLM to edit code with them from the command line. | Developers who want IDE-based coding assistance and the option to delegate scoped work to local or cloud agents. |
| Plans and cost | Aider's official linked repository publishes its software under Apache License 2.0, with a no-charge, royalty-free grant. You provide the model: paid APIs, free providers with limits, or local hardware. The software licence does not make external LLM usage or computing free. | The current official desktop page lists Free at $0/month, Pro at $20/month, and Max at $200/month. Currency is not explicitly labeled; verify checkout, agent scope, and existing account or plan migration before purchase. |
| Limitations | You supply the model access yourself, and results depend heavily on the capability of the model you connect. | The official desktop page now uses the Devin Desktop name; confirm existing Windsurf account and plan compatibility before switching. Agent output and cloud actions require diff review, tests, and access checks. |
Use the same input
Refactor a mid-size Python module with both tools: with Aider in the terminal and with Devin's agent, tracking total spend and the number of broken commits.
What a successful result must preserve
The refactor must land across multiple files, every change must be reviewable in git, and total cost for the session must stay under $5.
Evidence and test status
Pricing and feature comparison based on the vendors' official pages (Aider model-connection documentation and licence text; Devin pricing), observed October 2026. Older third-party roundups were not used as a current-price basis. We did not run a scored hands-on test; no quality ranking is claimed.
- Aider — Aider - AI Pair Programming in Your Terminal ↗, Aider Documentation | aider ↗, Voice-to-code with aider | aider ↗, Aider - AI Pair Programming in Your Terminal ↗, Aider - AI Pair Programming in Your Terminal ↗
- Devin Desktop (formerly Windsurf) — Devin Desktop, the current Windsurf-branded product page ↗ (reviewed 2026-10-15), Official Windsurf plugin changelog ↗ (reviewed 2026-10-15), Windsurf master services agreement ↗ (reviewed 2026-10-15)