🐜 Ant

An ant carries 50× its weight. So does this one.

Ant is a lightweight, high-performance JavaScript runtime built from scratch.
Built to carry more than it weighs without compromising performance.

$ ls -lh ant
-rwxr-xr-x⠀9.5M⠀ant*

# built with -Os
-rwxr-xr-x⠀5.8M⠀ant*

Table of contents

• Why Ant?
• Installation
• Benchmarks
• Spec conformance
• Building Ant
• Docker Images
• Security
• Community
• Contributing to Ant

Why Ant?

	Ant	Node	Bun	Deno
Binary size	~9 MB	~140 MB	~61 MB	~77 MB
Cold start	~4 ms	~30 ms	~10 ms	~18 ms
Engine	Ant Silver	V8	JSC	V8
JIT	✓	✓	✓	✓
WinterTC conformant	✓	partial	✓	✓

Ant is designed for environments where size and startup time matter: serverless functions, edge computing, embedded systems, CLI tools, and anywhere you'd want JavaScript but can't afford a 50MB+ runtime.

Ant Silver is an independent engine, not a wrapper around V8, JSC, or SpiderMonkey. The JIT compiler uses a fork of MIR, a lightweight backend that enables near-native performance.

Installation

curl -fsSL https://antjs.org/install | bash

Spec conformance

Ant targets the WinterTC Minimum Common API specification, the standard for server-side JavaScript interoperability developed by Ecma TC55.

Suite	Pass rate	Notes
compat-table	100%	1511/1511 (ES1–ES5, ES6, ES2016+, ESNext)
Temporal	100%	4603/4603 at revision 2026-08-10
test262	~75%	40243/53578 run on 2026-10-21

Benchmarks

Cold start

Measures the time to import Hono, register routes, and exit. Each runtime loads the same bench-coldstart.js script from examples/npm/hono/ that creates a Hono app with two routes, prints "ready", and calls process.exit(0). No HTTP server is actually started, this isolates module resolution and initialization overhead.

Measured with hyperfine (10 warmup runs, 100 timed runs):

hyperfine --warmup 10 --runs 100 \
  'ant  examples/npm/hono/bench-coldstart.js' \
  'node examples/npm/hono/bench-coldstart.js' \
  'bun  examples/npm/hono/bench-coldstart.js' \
  'deno run --allow-read --allow-env examples/npm/hono/bench-coldstart.js'

Runtime	Mean	Min	Max	Relative
Ant	3.9 ms	2.1 ms	5.3 ms	1.00
Bun	8.8 ms	6.7 ms	10.7 ms	2.26× slower
Deno	18.6 ms	16.2 ms	20.8ms	4.74× slower
Node	29.4 ms	27.3 ms	32.6 ms	7.50× slower

Environment

Detail	Value
Hardware	Apple M5 Pro, 64 GB RAM, 18 cores
OS	macOS 27.0 Golden Gate (26A5406e)
Ant	14.1.aa53d9d1.0
Node	26.5.1
Bun	1.4.0
Deno	2.9.5

Building Ant

See BUILDING.md for instructions on how to build Ant from source and a list of supported platforms.

Docker Images

Pull the published image for linux/amd64 or linux/arm64.

docker pull themackabu/ant:latest
docker run --rm themackabu/ant:latest --version
docker run --rm -v "$PWD:/app" themackabu/ant:latest index.js

You can also build the container from source:

docker build -t ant .
docker run --rm ant --version
docker run --rm -v "$PWD:/app" ant index.js

Security

For information on reporting security vulnerabilities in Ant, see SECURITY.md.

Community

• Discord
• Blog: Working was the beginning
• DeepWiki: Ant internals

Contributing to Ant

We welcome contributions through pull request. See CONTRIBUTING.md for more details.
For information about the governance of Ant, see GOVERNANCE.md.