
Mailman is a lightweight API testing and request-building tool designed to help developers quickly send HTTP requests, inspect responses, and organize API workflows. Similar to other API clients, Mailman allows you to build requests, store them in collections, and test APIs directly from your browser.
Collections allow you to organize multiple API requests into logical groups. Click "+ Collection" in the sidebar to create a new one, then add requests inside that collection for easier management.
Click "+ Request" to create a new API request. Give it a name and assign it to the collection you want to keep it in. This helps keep your API testing workflow organized.
Select the appropriate HTTP method such as GET, POST, PUT, PATCH, or DELETE. Then enter the API endpoint URL in the request field.
If the API requires authentication, choose an auth method such as Bearer Token or Basic Auth. Enter the required credentials in the fields that appear.
Headers allow you to provide additional request information such as
Content-Type, authorization tokens, or custom API headers.
Enter a key and value and click Add to include it in the request.
For POST, PUT, or PATCH requests you may need to include data in the body. Mailman supports multiple formats including:
Select the format from the dropdown and enter your data in the editor.
Environments allow you to store variables such as API keys, base URLs, or tokens.
Use variables inside requests using the syntax {{variable}}.
This makes it easy to switch between development, staging, and production APIs.
Click the Send button to execute the API request. The response will appear below showing the returned data, status, and response time.
Mailman automatically detects response types and lets you view them in multiple modes:
Mailman can generate code snippets for your requests. Select the desired language such as cURL, PHP (cURL), or .NET HttpClient, then click Generate. This allows you to quickly copy working API code into your application.
Quickly send HTTP requests and inspect responses without writing temporary scripts. Mailman provides a streamlined interface for testing endpoints during development.
With collections and saved requests, you can keep your API testing structured and easily revisit important endpoints.
Environments allow you to store reusable variables like API keys or base URLs, making it easy to switch between development and production systems.
Mailman supports various request body formats including JSON, XML, HTML, and raw text, giving you flexibility when working with different APIs.
Automatically generate working API request code in popular formats such as cURL, PHP, and .NET. This saves time and reduces the chance of mistakes when integrating APIs into your applications.
Responses can be viewed in formatted JSON, rendered HTML, or raw output, making debugging and data inspection easier.
Easily import or export collections and environment files to share with team members or migrate between systems.
Mailman runs directly in the browser without requiring heavy installations, making it fast, portable, and convenient for everyday API testing.