@rauchg: http://fx.sh is 6.3mb. It starts up in 10Β΅sΒΉ. It's a Zig-compiled static ELF binary, or an even smaller πππππ‘.π πβ¦
Summary
A new open-source coding agent tool named fx, compiled with Zig, features a tiny 6.3MB binary, instant startup in 10Β΅s, and WebAssembly support for optimized performance and embeddability.
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Cached at: 08/20/26, 03:05 PM
http://fx.sh is 6.3mb. It starts up in 10Β΅sΒΉ. Itβs a Zig-compiled static ELF binary, or an even smaller πππππ‘.π πππΒ²
AI will make most infrastructure natively optimized. Case in point: fx can literally finish tasks faster than other agents can boot.
Fast is a one-way street.
ΒΉ thatβs microseconds Β² fun fact: the wasm build is actually smaller. A lot of binary weight comes from the TLS/HTTP stack. In WebAssembly, fx delegates πππππ() to the JS runtime instead. You can try this on http://fx.sh/try
fx - Tiny, open, native coding agent
Source: https://fx.sh/ Tiny, open, native coding agent.
v0.0.4(notes)6.39mibstatus:experimentaluse at your own risk, we will be making frequent changes
This demo runs the full fx CLI as WebAssembly compiled with the Zig toolchain. Networking is delegated to browserfetch, and every SDK aspect is configurable in thedocs.
fxis a coding agent harness and CLI written in Zig, optimized for research and embeddability as part of larger systems.
It focuses on minimalism and performance across the board, from system prompt design, to its tools, feature set, and 6.39mib binary.
For end users, its CLI output style and form factor aims to be closer to a Unix shell than a heavy βIDE in the terminalβ TUI.
Itβs open source (Apache-2.0), model-agnostic, and suitable for both local and cloud inference.
Tiny ~6mb binary
Designed for instant installation and embedding in resource constrained environments and agent sandboxes.
Instant time to prompt
fx cold starts in10Β΅sand does no unnecessary work or I/O prior to accepting user input, making it ideal for programmatic use.
Wasm support
Optimal fx.wasm builds produced by the Zig toolchain, which further reduce fxβs size, making the network stack pluggable.
Minimal memory footprint
fx contributes single-digit megabytes of memory baseline, allowing you to pack many instances in one machine.
Shell-like UI and ergonomics
fx preserves scroll history by default, produces minimal output, and makes sparing use of complex TUI or paints
Context efficient
Minimal system prompt and tools, to save on token costs and to yield optimal time-to-first-token performance (TTFT).
Embeddable and extensible
Small core, extended via skills, plugins, MCPs, with a Unix-like philosophy to extensibility.
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