fx (by Vercel) vs Letta Code

Feature	fx (by Vercel)	Letta Code

Tagline	Tiny, open, embeddable, native coding agent by Vercel.	The memory-first coding agent
Website	https://fx.sh	https://letta.com
Language	zig	typescript
Release Date	August 17, 2026	December 16, 2025
Last Updated	August 19, 2026	August 19, 2026
Provider Type	Independent	Independent
MCP Support	Yes	Yes
Multi-Agent Support	No	Yes
Git Integration	basic	basic
Multi-File Editing	Yes	Yes
Auto Test Running	No	Yes
Sandbox / Permissions	Yes	Yes
Image / Multimodal Input	Yes	Yes
Voice Mode	No	No
IDE Integration	None - Terminal only	None - Terminal only
Hooks / Extensions	No	Yes
Web Search	Yes	Yes
Local Model Support	Yes	Yes
Context Window	Model-dependent	Model-dependent
Terminal Bench		#44 · 59.1% ±2.4 (Terminal-Bench 2.0) ²
Supported Models	All Vercel AI Gateway supported models, including OpenAI, Anthropic, Google, DeepSeek, z.AI, Moonshot, etc	Multi-provider with Claude, GPT, Gemini and self-hosted (BYOK).
Supported Subscriptions	-	ChatGPT GitHub Copilot Claude Code OpenCode Go / Zen
Pricing Model	Free, BYOK, Usage Based	Freemium
Free Tier	No	Yes
Price Range	0 - $20 / mo / Custom (Vercel AI Gateway)	Free (BYOK) / $20-200/mo
Source Code Availability	Open Source (Apache-2.0)	Open Source (Apache-2.0)
Source Code	https://github.com/vercel-labs/fx	c
Development State	active	active