fx

fx

Vercel
+
+

Related Products

  • BAND
    3 Ratings
    Visit Website
  • Retool
    593 Ratings
    Visit Website
  • JetBrains Junie
    12 Ratings
    Visit Website
  • Google AI Studio
    30 Ratings
    Visit Website
  • cside
    37 Ratings
    Visit Website
  • Admin By Request Endpoint Privilege Management
    97 Ratings
    Visit Website
  • Gemini Enterprise Agent Platform
    999 Ratings
    Visit Website
  • Okyline
    2 Ratings
    Visit Website
  • LM-Kit.NET
    29 Ratings
    Visit Website
  • Lenso.ai
    2 Ratings
    Visit Website

About

Reasonix is an open source coding agent designed for long autonomous sessions that remain readable, auditable, and reversible. One local engine powers four interfaces: terminal, desktop app, browser, and ACP-compatible editors, with sessions, permissions, skills, and MCP servers shared across them. Plan mode holds every write until the proposed steps are reviewed and approved, while reads, writes, and shell commands are separately gated and constrained by a workspace sandbox. Each turn creates a checkpoint outside Git, allowing users to rewind a long run without affecting commit history. MCP support over stdio, SSE, and streamable HTTP merges external tools into one registry, while Markdown skills and isolated subagents extend the agent without requiring a fork. Reasonix maps a codebase once and keeps that map throughout the session, letting users queue tasks, review diffs, and resume work without losing context.

About

fx is a tiny, open, native coding agent harness and CLI written in Zig, optimized for research, performance, and embeddability as part of larger systems. Its design focuses on minimalism across the system prompt, tools, feature set, memory use, and a 6 MB binary, with an interface intended to feel closer to a Unix shell than a heavy terminal IDE. fx cold starts in microseconds and performs no unnecessary work or I/O before accepting input, making it suitable for programmatic use, resource-constrained environments, and agent sandboxes. Developers can start it inside a project and ask it to read files, search code, run commands, make changes, execute tests, and stream tool calls as they happen. The core is model- and provider-agnostic, supporting local models, gateways, direct provider access, and cloud inference. It is context-efficient by design, using a minimal system prompt and toolset to reduce token overhead and improve time to first token.

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Platforms Supported

Windows
Mac
Linux
Cloud
On-Premises
iPhone
iPad
Android
Chromebook

Audience

Software developers and engineering teams wanting a tool to run long, auditable AI coding sessions, automate repository work, and extend agent capabilities across terminal, desktop, browser, and editor workflows

Audience

Developers and AI infrastructure builders in need of a solution to run or embed a lightweight, extensible, model-agnostic coding agent in terminals, applications, and automated systems

Support

Phone Support
24/7 Live Support
Online

Support

Phone Support
24/7 Live Support
Online

API

Offers API

API

Offers API

Screenshots and Videos

Screenshots and Videos

Pricing

Free
Free Version
Free Trial

Pricing

Free
Free Version
Free Trial

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Reviews/Ratings

Overall 0.0 / 5
ease 0.0 / 5
features 0.0 / 5
design 0.0 / 5
support 0.0 / 5

This software hasn't been reviewed yet. Be the first to provide a review:

Review this Software

Training

Documentation
Webinars
Live Online
In Person

Training

Documentation
Webinars
Live Online
In Person

Company Information

Reasonix
China
reasonix.io

Company Information

Vercel
Founded: 2015
United States
fx.sh/

Alternatives

Claude Code

Claude Code

Anthropic

Alternatives

OpenClaw

OpenClaw

Molty

Categories

Categories

Integrations

DeepSeek
DeepSeek-V4-Flash
DeepSeek-V4-Pro
Model Context Protocol (MCP)

Integrations

DeepSeek
DeepSeek-V4-Flash
DeepSeek-V4-Pro
Model Context Protocol (MCP)
Claim Reasonix and update features and information
Claim Reasonix and update features and information
Claim fx and update features and information
Claim fx and update features and information