Blast

Blast is a fast, config-driven API load tester, traffic generator, and mock server written in Rust.

Describe your API once in a blast.config.json file, then hit every endpoint with a single command — fake data, request chaining, load tests, stress tests, and a built-in mock server, all without writing code.

Full documentation at blast.walonfoundation.com

Quick start

# Install
curl -fsSL https://raw.githubusercontent.com/Walon-Foundation/blast/main/install.sh | sh

# Create a starter config
blast init

# Validate and check endpoints
blast validate
blast check

# Seed a database with fake data
blast seed --count 50 --concurrency 5

# Load test at a fixed rate
blast run --rps 20 --duration 60

# Stress test — find the breaking point
blast stress --min-rps 10 --max-rps 100 --step 10 --step-duration 15

# Start a mock server from your config
blast mock

Install

Pre-built binaries for Linux (x86_64, arm64), macOS Apple Silicon, and Windows x86_64 — see the install guide or grab the latest from GitHub Releases.

To build from source:

git clone https://github.com/Walon-Foundation/blast.git
cd blast
cargo install --path .

Commands

Command	Description
blast init [path]	Create a starter blast.config.json
blast check	Hit every endpoint once, verify status codes
blast validate	Validate blast.config.json
blast seed	Seed a database with fake data iterations
blast run	Fixed-RPS load test with latency percentiles
blast stress	Ramp RPS and detect the breaking point
blast mock	Start a local mock server from your config

Features

• Config-driven — one JSON file, no scripting
• Fake data — {{fake.email}}, {{fake.uuid}}, {{fake.name}}, and more
• Request chaining — extract values from responses, reuse as {{variable}}
• Load testing — fixed RPS, live progress, p50/p95/p99/p999 latency
• Stress testing — auto-detect the breaking point
• Mock server — prototype against realistic responses before the backend exists
• Setup phase — run auth/warm-up requests before load tests
• CI friendly — non-zero exit code on failure

License

MIT — see LICENSE.

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Built by the Walon Foundation.