Pre-request & Test Scripts

Each request has a Scripts tab with two editors: a pre-request script, run just before the request is sent, and a test script, run after the response arrives. Both are plain JavaScript with access to a small pm object, similar to Postman's sandbox.

pm API

• pm.environment.get(key) — read a variable from the active environment
• pm.environment.set(key, value) — create or update a variable in the active environment
• pm.environment.unset(key) — remove a variable
• pm.globals.get(key) / pm.globals.set(key, value) / pm.globals.unset(key) — same, but for global variables (always accessible regardless of active environment)
• pm.iterationData.get(key) — read a column from the attached data file; always returns undefined outside a data-driven run (read-only)
• pm.response.status / pm.response.statusText — response status (test scripts only)
• pm.response.headers — response headers object (test scripts only)
• pm.response.responseTime — elapsed time in ms (test scripts only)
• pm.response.json() — parse the response body as JSON (test scripts only)
• pm.response.text() — raw response body as a string (test scripts only)
• pm.test(name, fn) — register a named test; fn throwing marks it failed
• pm.expect(value) — chainable matchers: .toBe(), .toEqual(), .toBeTruthy(), .toBeFalsy(), .toBeDefined(), .toBeNull(), .toContain(), .toHaveProperty(), .toBeGreaterThan(), .toBeLessThan(), plus .not to negate any of them

Example: pre-request script

Set a fresh timestamp on every send:

pm.environment.set('timestamp', Date.now());

Example: test script

Assert on the response and pull a value into an environment variable for later requests:

pm.test('status is 200', () => {
  pm.expect(pm.response.status).toBe(200);
});

pm.test('response is not an error', () => {
  pm.expect(pm.response.json()).not.toHaveProperty('error');
});

pm.environment.set('userId', pm.response.json().id);

Test results show up in a Tests tab in the response panel, with a pass/fail count badge. Scripts that throw outside of pm.test() (a syntax error, etc.) show up as a single failed test.