Aider vs. fx (by Vercel)

Feature	Aider	fx (by Vercel)

Tagline	AI pair programming in your terminal	Tiny, open, embeddable, native coding agent by Vercel.
Website	https://aider.chat	https://fx.sh
Language	python	zig
Release Date	July 8, 2023	August 17, 2026
Last Updated	June 29, 2026	August 19, 2026
Provider Type	Independent	Independent
MCP Support	No	Yes
Multi-Agent Support	No	No
Git Integration	deep	minimal
Multi-File Editing	Yes	Yes
Auto Test Running	Yes	No
Sandbox / Permissions	No	Yes
Image / Multimodal Input	Yes	Yes
Voice Mode	Yes	No
IDE Integration	VS Code, Neovim, Emacs
Hooks / Extensions	Yes	No
Web Search	No	Yes
Local Model Support	Yes	Yes
Context Window	Model-dependent	Model dependent
Supported Models	Claude Sonnet 4.5/4.6, Claude Opus 4.5/4.6, GPT-5.4, GPT-4o, DeepSeek, Gemini, Llama, Qwen	All Vercel AI Gateway supported models, including OpenAI, Anthropic, Google, DeepSeek, z.AI, Moonshot, etc
Pricing Model	BYOK	Free, BYOK, Usage Based
Free Tier	Yes	No
Price Range	Free (BYOK)	0 - $20 / mo / Custom (Vercel AI Gateway)
Source Code Availability	Open Source (Apache-2.0)	Open Source (Apache-2.0)
Source Code	https://github.com/Aider-AI/aider	https://github.com/vercel-labs/fx
Development State	active	active