fx (by Vercel) vs. Mastra Code

Feature	fx (by Vercel)	Mastra Code

Tagline	Tiny, open, embeddable, native coding agent by Vercel.	Coding agent that replaces compaction with Observational Memory
Website	https://fx.sh	https://code.mastra.ai/
Language	zig	typescript
Release Date	August 17, 2026	December 24, 2025
Last Updated	August 19, 2026	September 4, 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	No
Sandbox / Permissions	Yes	Yes
Image / Multimodal Input	Yes	Yes
Voice Mode	No	Yes
IDE Integration	None - Terminal only	ACP (Agent Client Protocol)
Hooks / Extensions	No	Yes
Web Search	Yes	Yes
Local Model Support	Yes	Yes
Context Window	Model-dependent	Model-dependent; observation-based
Supported Models	All Vercel AI Gateway supported models, including OpenAI, Anthropic, Google, DeepSeek, z.AI, Moonshot, etc	Claude, GPT, Gemini and thousands more via Mastra's unified model router, plus custom OpenAI-compatible providers
Supported Subscriptions	—	Claude Code ChatGPT GitHub Copilot SuperGrok
Pricing Model	Free, BYOK, Usage Based	Free, BYOK
Free Tier	No	Yes
Price Range	0 - $20 / mo / Custom (Vercel AI Gateway)	Free (BYOK)
Source Code Availability	Open Source (Apache-2.0)	Open Source (Apache-2.0)
Source Code	https://github.com/vercel-labs/fx	https://github.com/mastra-ai/mastra
Development State	active	active