Introduction

@t-req/core is an HTTP request parsing, execution, and testing library. Define requests in .http files, test them in isolation.

What is @t-req/core?

@t-req/core lets you write HTTP requests in standard .http files—the same format used by VS Code REST Client and JetBrains HTTP Client—and execute them programmatically with TypeScript or JavaScript.

Key Features

• Parse .http files - Standard format, no proprietary syntax
• Variable interpolation - {{variable}} syntax with custom resolvers
• Native fetch Response - Returns standard Response objects, no wrapper
• Cookie management - Automatic cookie jar with RFC 6265 compliance
• Timeout & cancellation - Built-in timeout and AbortSignal support
• TypeScript first - Full type definitions included

Philosophy

Requests are just code. No DSL, no hidden state machines. Each .http file contains one request, and you orchestrate them with standard JavaScript:

// Login and get token
const login = await client.run('./auth/login.http');
const { token } = await login.json();

// Use token for subsequent requests
client.setVariable('token', token);

// Fetch profile
const profile = await client.run('./users/profile.http');

// Standard control flow for complex scenarios
for (const id of userIds) {
  await client.run('./users/get.http', { variables: { userId: id } });
}

Runtime Support

@t-req/core runs on:

• Node.js (>=18) - Pass io: createNodeIO() when creating the client
• Bun (>=1.0) - Works out of the box, uses Bun’s filesystem APIs
• Tauri/Desktop - Renderer-safe via runString() for in-memory content

When to Use @t-req/core

Use the library (@t-req/core) when you need:

• Programmatic control - Execute requests from your TypeScript/JavaScript code
• API testing - Write requests once, run them in tests
• Building tools - Create your own CLI, GUI, or automation on top of @t-req/core
• CI/CD pipelines - Automate API testing in your build process

Use the CLI (coming soon) when you need:

• Quick one-off request execution from the terminal
• Interactive exploration without writing code

Next Steps

Ready to get started? Head to the Installation guide to add @t-req/core to your project.