Scripting API Overview

Complete reference for Bruno’s JavaScript scripting API

Bruno provides a powerful JavaScript runtime for scripting and automation. You can write scripts in three contexts: pre-request scripts, post-response scripts, and tests.

Available Contexts

Bruno scripts run in a sandboxed JavaScript environment with access to:

• Pre-request scripts (script:pre-request): Run before the request is sent
• Post-response scripts (script:post-response): Run after the response is received
• Tests (tests): Run after the response to validate results

Global Objects

All scripts have access to these global objects:

bru · object

The main Bruno API object for managing variables, environment, and request flow

req · BrunoRequest

The request object (available in pre-request and post-response scripts)

res · BrunoResponse

The response object (available in post-response scripts and tests only)

test · function

Function to define test assertions

expect · object

Chai’s expect assertion library

assert · object

Chai’s assert assertion library

console · object

Console logging object with log(), info(), warn(), error(), and debug() methods

Built-in Libraries

Bruno includes several built-in libraries that you can access using require():

chai

Assertion library (automatically available as expect and assert)

moment

Date and time manipulation library

btoa

Base64 encoding function

atob

Base64 decoding function

crypto-js

Cryptographic functions

jsonwebtoken

JWT creation and verification

buffer

Buffer implementation for binary data

tv4

JSON schema validation

Example Usage

Pre-request Script

script:pre-request {
  // Set authentication header
  const token = bru.getEnvVar('api_token');
  req.setHeader('Authorization', `Bearer ${token}`);
  
  // Modify request body
  const body = req.getBody();
  body.timestamp = Date.now();
  req.setBody(body);
}

Script Execution Order

When a request is executed, scripts run in this order:

1. Pre-request script - Modify request before sending
2. HTTP Request - Send the request
3. Post-response script - Process the response
4. Assertions - Run declarative assertions from assert block
5. Tests - Run test scripts

Runtime Modes

Bruno supports two runtime modes:

Safe Mode (QuickJS)

The default runtime that provides a secure, sandboxed environment. Recommended for most use cases.

• Limited file system access
• Better security
• Faster startup time

Check if running in safe mode:

if (bru.isSafeMode()) {
  console.log('Running in safe mode');
}

Node VM Mode

A more permissive runtime with full Node.js capabilities. Enable this in collection settings for advanced scripting needs.

• Full file system access
• Additional Node.js modules
• Custom library imports

Next Steps

Pre-request API

Modify requests before they are sent

Post-response API

Process responses and extract data

Test API

Write assertions and validate responses

Advanced Scripting

Common scripting patterns and examples