## Sarin is a high-performance HTTP load testing tool built with Go and fasthttp.
[](https://pkg.go.dev/go.aykhans.me/sarin)
[](https://hub.docker.com/r/aykhans/sarin)
[](https://github.com/aykhans/sarin/releases)
[](https://github.com/aykhans/sarin/actions/workflows/lint.yaml)
[](https://opensource.org/licenses/MIT)
Install •
Quick Start •
Examples •
Configuration •
Templating
## Overview
Sarin is designed for efficient HTTP load testing with minimal resource consumption. It prioritizes simplicity and features like templating add zero overhead when unused.
| ✅ Supported | ❌ Not Supported |
| ---------------------------------------------------------- | ------------------------------- |
| High-performance with low memory footprint | Web UI or complex TUI |
| Dynamic requests via 340+ template functions | Detailed response body analysis |
| Request scripting with Lua and JavaScript | Distributed load testing |
| Multiple proxy protocols
(HTTP, HTTPS, SOCKS5, SOCKS5H) | HTTP/2, HTTP/3, WebSocket, gRPC |
| Captcha solving
(2Captcha, Anti-Captcha, CapSolver) | Plugins / extensions ecosystem |
## Installation
Docker
```sh
docker run --rm -it aykhans/sarin:latest --version
```
With a local config file:
```sh
docker run --rm -it -v /path/to/config.yaml:/config.yaml aykhans/sarin -f /config.yaml
```
With a remote config file:
```sh
docker run --rm -it aykhans/sarin -f https://example.com/config.yaml
```
Nix
Run directly without installing (requires flakes enabled):
```sh
nix run github:aykhans/sarin/release -- -U http://example.com -r 100 -c 10
```
Install into your profile:
```sh
nix profile install github:aykhans/sarin/release
```
Or add it to your own flake via the overlay:
```nix
{
inputs.sarin.url = "github:aykhans/sarin/release";
# In your outputs, apply the overlay to nixpkgs:
# nixpkgs.overlays = [ inputs.sarin.overlays.default ];
# then reference pkgs.sarin
}
```
The `release` branch tracks the newest stable release cut from `main`, so `nix flake update` moves between releases rather than following every commit; pre-releases are excluded. Pin an exact release with `github:aykhans/sarin/v1.4.2`, or track development with `github:aykhans/sarin` (the `main` branch).
Pre-built Binaries
Download the latest binaries from the [releases](https://github.com/aykhans/sarin/releases) page.
Building from Source
Requires the [Go version declared in `go.mod`](go.mod).
```sh
git clone https://github.com/aykhans/sarin.git && cd sarin
CGO_ENABLED=0 go build \
-ldflags "-X 'go.aykhans.me/sarin/internal/version.Version=dev' \
-X 'go.aykhans.me/sarin/internal/version.GitCommit=$(git rev-parse HEAD)' \
-X 'go.aykhans.me/sarin/internal/version.BuildDate=$(date -u +%Y-%m-%dT%H:%M:%SZ)' \
-X 'go.aykhans.me/sarin/internal/version.GoVersion=$(go version)' \
-s -w" \
-o sarin ./cmd/cli/main.go
```
## Quick Start
Send 10,000 GET requests with 50 concurrent connections and a random User-Agent for each request:
```sh
sarin -U http://example.com -r 10_000 -c 50 -H "User-Agent: {{ fakeit_UserAgent }}"
```
Run a 5-minute duration-based test:
```sh
sarin -U http://example.com -d 5m -c 100
```
Use a YAML config file:
```sh
sarin -f config.yaml
```
For more usage examples, see the **[Examples Guide](docs/examples.md)**.
## Configuration
Sarin supports environment variables, CLI flags, and YAML files. When the same option is specified in multiple sources, the following priority order applies:
```
CLI Flags (Highest) > YAML > Environment Variables (Lowest)
```
For detailed documentation on all configuration options (URL, method, timeout, concurrency, headers, cookies, proxy, etc.), see the **[Configuration Guide](docs/configuration.md)**.
## Templating
Sarin supports Go templates in URL paths, methods, bodies, headers, params, cookies, and values. Use the 340+ built-in functions to generate dynamic data for each request.
**Example:**
```sh
sarin -U "http://example.com/users/{{ fakeit_UUID }}" -r 1000 -c 10 \
-V "REQUEST_ID={{ fakeit_UUID }}" \
-H "X-Request-ID: {{ .Values.REQUEST_ID }}" \
-B '{"request_id": "{{ .Values.REQUEST_ID }}"}'
```
For the complete templating guide and functions reference, see the **[Templating Guide](docs/templating.md)**.
## License
This project is licensed under the MIT License. See the [LICENSE](LICENSE) file for details.