Building Requests in Postmate Client

Build and send HTTP and REST API requests in VS Code using Postmate Client — a fast, privacy-first Postman alternative.

Postmate Client provides a request panel designed to minimise typing and maximise speed. Autocomplete works across headers, variables, body, and test data — so you can build fully configured requests in seconds without remembering variable names or headers.

Unlike Postman or Thunder Client, Postmate Client runs entirely locally, keeping your API data private.

The Request Panel

Every request is split into two sides:

• Left panel — design your request: URL, method, headers, body, scripts, and tests
• Right panel — view the response: body, headers, and test results

At the top of the left panel: the HTTP method dropdown and the URL bar. At the top-right: the Env dropdown to switch environments instantly.

Setting the URL & Environment

Enter your endpoint URL directly, or type {{ to trigger variable autocomplete. Postmate lists variables from the active environment and data table instantly — just select one to insert it.

Switch environments using the Env dropdown in the top-right. Selecting an environment updates every {{variable}} in your URL, headers, and body automatically.

Postmate simplifies request building with inline autocomplete and zero-config environments — no memorisation, no typos.

Headers Tab

The Headers tab displays a key-value table for all request headers.

Two layers of autocomplete work here:

1. Header name autocomplete — start typing any header name and Postmate lists matching headers from your Manage Headers file. Select one and the default value is filled in automatically.

2. Variable autocomplete — anywhere in the value column, type {{ and Postmate lists variables from the active environment and data table. Select the variable — no memorising names, no spelling mistakes.

Each header row has a checkbox to enable/disable it without deleting it, and a delete icon to remove it entirely.

Body Tab

Click the Body tab to set the request body. Choose your content type using the radio buttons at the top:

Format	Use case
JSON	REST APIs returning/accepting JSON
XML	SOAP or XML-based APIs
x-www-form-urlencoded	HTML form submissions
Text	Plain text payloads
multipart/form-data	File uploads and mixed content

Auto-format — after writing a JSON or XML body, click the Format link to instantly pretty-print and indent the content. No manual formatting needed.

Variable autocomplete works across all fields in the Postmate Client request panel — type {{ anywhere to insert environment or data-table variables instantly.

Auth Tab

Click the Auth tab to configure authentication for the request. Select your auth type and fill in the required fields — Postmate sets the correct headers automatically.

For token-based auth, reference a variable so it stays in sync across environments:

Bearer {{accessToken}}

Pre-request Tab

The Pre-request tab lets you run logic before the request is sent. It has two sub-tabs:

Pre-request — chain an existing request from any collection. Use the Collection dropdown to pick a collection, then the Request dropdown to pick the specific request. Add multiple pre-requests with + Add Request. Postmate executes them in order before sending the main request — perfect for running a login request first to capture a token.

Scripting — write full JavaScript to set variables, generate dynamic values, or run any pre-send logic.

→ See Request Chaining for the full chaining guide
→ See Pre/Post Scripts for the scripting reference

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Post-request Tab

The Post-request tab runs after the response is received. It has two sub-tabs:

Test — Plain English Assertions

Write assertions as table rows — no code required. Each row is one test with four fields:

Field	Description
JSON path	Pick the response field to check — autocompleted from the last response (e.g. $.schoolInof.schoolName)
Operator	equal, contains, =, set to, and more
Expected value	The value you expect
Test description	A human-readable label shown in the Results panel

The first column also supports Set to — which stores the response value into an environment variable rather than asserting against it. This is how you chain a value from one response into the next request without writing a script.

Script — Full JavaScript

For advanced logic, switch to the Script tab and write JavaScript directly. The Monaco-based editor provides syntax highlighting, pm.* autocomplete, and a Snippets button (bottom-right) that inserts ready-made patterns.

const resp       = RESPONSE.body;
const schoolInof = resp.schoolInof;
const stud       = resp.students;

pm.test('Verify status 200', () => {
  pm.expect(RESPONSE.status).to.be.equal(200);
});

pm.test('Verify schoolName is correct', () => {
  pm.expect(schoolInof.schoolName).to.be.equal('ABC Learning Academy');
});

→ See Tests & Assertions for the full plain-English test guide
→ See Pre/Post Scripts for the full scripting reference
→ See pm Library Reference for all available pm.* methods

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Select Data

At the bottom of the request panel, the Select Data field lets you pick a row from the data table attached to the active environment. Start typing to filter rows by any column value — matching rows appear instantly.

Select a row and its values are injected as variables into the request at send time. Combined with the Env dropdown, this gives you the 3-second workflow: pick environment, pick data row, click Send.

TIP

Run your request once before writing Post-request tests. Postmate will have the actual response available, so JSON path suggestions in the Test tab are populated from real data — no guessing field names.

Conclusion

Postmate Client makes building API requests in VS Code fast, reliable, and error-free with powerful autocomplete, environment variables, and built-in testing.

If you're looking for a secure, no-login Postman alternative, Postmate gives you everything you need — directly inside your editor.

FAQs

How do I build an API request in Postmate Client?

Use the request panel to define URL, method, headers, and body. Autocomplete helps you quickly insert variables and headers without memorising them.

Does Postmate support environment variables?

Yes, Postmate supports environment variables and data tables. You can use anywhere in your request.

Is Postmate Client a Postman alternative?

Yes, Postmate Client is a lightweight, privacy-first Postman alternative that runs entirely inside VS Code without requiring login or cloud sync.