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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.

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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

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Global Objects

All scripts have access to these global objects:
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bru
object
The main Bruno API object for managing variables, environment, and request flow
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req
BrunoRequest
The request object (available in pre-request and post-response scripts)
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res
BrunoResponse
The response object (available in post-response scripts and tests only)
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test
function
Function to define test assertions
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expect
object
Chai’s expect assertion library
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assert
object
Chai’s assert assertion library
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console
object
Console logging object with log(), info(), warn(), error(), and debug() methods

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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

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Example Usage

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);
}

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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

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Runtime Modes

Bruno supports two runtime modes:
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');
}
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

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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

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