π Ant
An ant carries 50Γ 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-xβ 8.7Mβ ant*
# built with -Os
-rwxr-xr-xβ 4.4Mβ ant*
Table of contents
- Why Ant?
- Installation
- Benchmarks
- Spec conformance
- Building Ant
- Security
- Community
- Contributing to Ant
Why Ant?
| Ant | Node | Bun | Deno | |
|---|---|---|---|---|
| Binary size | ~9 MB | ~140 MB | ~61 MB | ~77 MB |
| Cold start | ~5 ms | ~31 ms | ~13 ms | ~25 ms |
| Engine | Ant Silver | V8 | JSC | V8 |
| JIT | β | β | β | β |
| WinterTC conformant | β | partial | β | β |
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.
The engine, Ant Silver is hand-built, not a wrapper around V8, JSC, or SpiderMonkey. The JIT compiler uses a fork of MIR, a lightweight backend that enables near compiled 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 (ES1βES5, ES6, ES2016+, ESNext) |
| Temporal | 100% | 4603/4603 at revision 2026-08-10 |
| test262 | ~65% | 34758/53578 at revision 2026-08-10 |
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 | 5.5 ms | 4.9 ms | 6.1 ms | 1.00 |
| Bun | 10.6 ms | 9.5 ms | 13.8 ms | 1.93Γ slower |
| Deno | 24.8 ms | 22.2 ms | 29.4 ms | 4.51Γ slower |
| Node | 28.7 ms | 27.1 ms | 31.2 ms | 5.22Γ slower |
Environment
| Detail | Value |
|---|---|
| Hardware | Apple M5 Pro, 64 GB RAM, 18 cores |
| OS | macOS 26.5.1 (arm64) |
| Ant | 12.1.15dd25d.1 |
| Node | 26.2.0 |
| Bun | 1.3.14 |
| Deno | 2.8.3 |
Building Ant
See BUILDING.md for instructions on how to build Ant from source and a list of supported platforms.
Security
For information on reporting security vulnerabilities in Ant, see SECURITY.md.
Community
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.
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