Data Tables (Data-Driven API Testing in VS Code)

Run data-driven API testing in Visual Studio Code using Postmate Client. Data Tables let you parameterize API requests using CSV-style datasets, making it easy to test multiple scenarios with different inputs.

Postmate Client is a privacy-first Postman alternative that keeps all your test data local while supporting powerful automation features like collections, environments, and scripting.

This makes Postmate Client ideal for data-driven API testing in VS Code, similar to Postman Collection Runner with CSV data — but fully local and privacy-first.

What is a Data Table in API Testing?

A Data Table is a structured dataset (like a spreadsheet) used to run API requests with multiple inputs.

• Each column = variable name
• Each row = one test case
• Works with syntax

Example: API test data table test-users

username	password	expectedStatus
alice@example.com	pass123	200
bob@example.com	wrongpass	401
admin@example.com	admin123	200

Perfect for:

• Login API testing
• Negative test cases
• Bulk API validation

Environment-Scoped Data Tables

Unlike traditional API tools, Postmate Client supports environment-scoped data tables.

Attach different datasets to:

• Dev environment
• Staging environment
• Production environment

When you switch environments, your test data automatically switches too.

This makes it ideal for:

• Environment-specific testing
• Safe production validation
• Clean separation of test data

How to Attach a Data Table to an Environment

1. Open the Env tab in the sidebar
2. Select your environment (Dev, Staging, Prod)
3. Click Data Tables → New Table
4. Add columns and rows

Once attached:

• No need to reselect
• Automatically persists across sessions
• Always synced with environment

Using Data Tables in API Requests

Reference columns using standard variable syntax:

Reference any column name exactly like an environment variable using {{variableName}} syntax:

POST {{baseUrl}}/auth/login
Content-Type: application/json

{
  "email":    "{{username}}",
  "password": "{{password}}"
}

• Select environment
• Choose a data row
• Click Send

Postmate Client injects variables dynamically at runtime.

TIP

For running all rows in sequence, use the Collection Runner for data-driven API testing automation in VS Code.

Run Data-Driven Tests with Collection Runner

Use the Collection Runner to execute API tests across all rows automatically.

• Iterates through each row
• Runs full request flow
• Generates pass/fail results

👉 Ideal for:

• **Automated API testing
• Regression testing
• Bulk validation**

Import CSV for API Testing

Already have test data?

Import it instantly:

1. Open Data Tables panel
2. Click Import CSV
3. Upload file
4. First row → column names
5. Remaining rows → test cases

Key Behaviors

• Unlimited tables — create as many tables as your project needs, with no row or column limits.
• Environment-scoped — each table is attached to one environment; switching environments automatically switches the active table.
• Always attached — once a table is linked to an environment it stays linked across sessions.
• Works anywhere variables work — use {{columnName}} in URLs, headers, request bodies, and test scripts.

Why Use Data Tables in Postmate Client?

If you're looking for:

• A Postman alternative in VS Code
• Data-driven API testing tools
• Local-first API testing (no cloud sync)
• Better handling of test data across environments

Data Tables give you a clean, scalable way to manage API test inputs.