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Welcome to Antiposta
Antiposta is a lightweight API testing tool that runs entirely in your browser. No data is sent to any server unless you explicitly make an API request.
Basic Usage
Enter a URL in the request URL field
Select the HTTP method (GET, POST, etc.)
Configure headers, parameters, or body if needed
Click the Send button to make the request
View the response below
Key Features
Make HTTP requests with different methods
Set custom headers
Add URL parameters
Send different types of request bodies (JSON, form data, text)
View formatted responses
Use environments to store and reuse variables
Export requests as cURL commands
Automatic request history
Keyboard Shortcuts
Ctrl/Cmd + Enter : Send requestCtrl/Cmd + L : Focus URL barCtrl/Cmd + K : Copy as cURLF1 : Show helpEscape : Close modals
Click on a topic in the sidebar to learn more about specific features.
Request URL
The request URL is the address of the API endpoint you want to call.
HTTP Methods
Select the appropriate HTTP method for your request:
GET : Retrieve data from the serverPOST : Send data to create a resourcePUT : Update an existing resourceDELETE : Remove a resourcePATCH : Partially update a resourceHEAD : Same as GET but returns only headersOPTIONS : Get supported methods for a resource
Using Environment Variables
You can use environment variables in your URL with the {{variableName}} syntax.
Example: https://{{baseUrl}}/api/users
See the Environments section for more details.
Parameters
URL parameters are appended to the URL as a query string.
Adding Parameters
Click the "Add Parameter" button
Enter the parameter name in the Key field
Enter the parameter value in the Value field
Parameters will be automatically appended to your URL when you send the request.
Example: If your URL is https://api.example.com/users and you add a parameter page=2, the final URL will be https://api.example.com/users?page=2
Using Environment Variables
You can use environment variables in parameters with the {{variableName}} syntax.
Example: user_id: {{userId}}
Request Body
The request body contains data you want to send to the server. It's typically used with POST, PUT, and PATCH requests.
Body Types
None : No body is sent with the requestJSON : Send data in JSON formatForm Data : Send data as form fieldsRaw Text : Send plain text data
JSON
For JSON bodies, enter valid JSON in the editor. The editor will automatically format your JSON when you click outside the text area.
Example:
{
"name": "John Doe",
"email": "john@example.com"
}
Form Data
For form data, add key-value pairs that will be sent as application/x-www-form-urlencoded or multipart/form-data.
Raw Text
For raw text, simply enter the text you want to send. This is useful for custom formats or plain text.
Using Environment Variables
You can use environment variables in the request body with the {{variableName}} syntax.
Authentication
Authentication allows you to identify yourself to the API.
This feature will be implemented in a future update.
Common Authentication Methods
Basic Auth : Username and password encoded in Base64Bearer Token : JWT or OAuth token sent in the Authorization headerAPI Key : A key sent in headers, query parameters, or cookiesOAuth 2.0 : Token-based authentication with various flows
Using Environment Variables
It's recommended to store authentication credentials as environment variables for security and reusability.
Example: Authorization: Bearer {{accessToken}}
Response
The response section shows the result of your API request.
Response Information
Status : The HTTP status code and text (e.g., 200 OK, 404 Not Found)Time : How long the request took to completeSize : The size of the response body
Response Tabs
Response : Shows the response body. JSON responses are automatically formatted.Headers : Shows the response headers returned by the server.
Status Codes
Common HTTP status codes:
2xx : Success (200 OK, 201 Created, 204 No Content)3xx : Redirection (301 Moved Permanently, 302 Found)4xx : Client Error (400 Bad Request, 401 Unauthorized, 404 Not Found)5xx : Server Error (500 Internal Server Error, 503 Service Unavailable)
Environments
Environments allow you to store variables that can be reused across requests.
Creating an Environment
Click the "Manage Environments" button at the bottom of the screen
Enter a name for your environment and click "Add"
Select the environment from the list
Add variables with their values
Click "Save Changes"
Using Environment Variables
You can use environment variables in your requests with the {{variableName}} syntax.
Examples:
URL: https://{{baseUrl}}/api/users
Headers: Authorization: Bearer {{token}}
Body: {"userId": "{{userId}}"}
Switching Environments
Use the environment selector at the bottom of the screen to switch between environments.
Use Cases
Switching between development, staging, and production APIs
Storing authentication tokens
Reusing common values across multiple requests
cURL Export
Antiposta can generate cURL commands from your requests, making it easy to share requests or use them in scripts.
Using cURL Export
Configure your request (URL, method, headers, body, etc.)
Click the "📋 cURL" button next to the Send button
The cURL command will be automatically copied to your clipboard
Paste it into your terminal or scripts
Keyboard Shortcut
You can also use Ctrl/Cmd + K to quickly copy the current request as a cURL command.
What's Included
The generated cURL command includes:
HTTP method (-X flag)
All headers (-H flags)
URL parameters (appended to URL)
Request body (-d flag for JSON, form data, or text)
Environment variables are resolved to their actual values
Example Output
curl -X POST \
-H "Content-Type: application/json" \
-H "Authorization: Bearer token123" \
-d '{"name": "John", "email": "john@example.com"}' \
"https://api.example.com/users"
Tips
Environment variables are automatically replaced with their values
Use this feature to document API calls in your projects
Perfect for sharing requests with team members
Great for converting GUI requests to automation scripts
Request History
Antiposta automatically saves your recent requests, making it easy to repeat or modify previous API calls.
How It Works
Every successful request is automatically saved to history
History is stored locally in your browser
The 20 most recent requests are kept
Duplicate requests (same method + URL) are merged
Using History
Look for the "History" panel in the left sidebar
Click on any history item to load that request
All request details are restored: headers, parameters, body, etc.
Make any needed modifications and send again
History Information
Each history item shows:
HTTP Method : GET, POST, etc.URL : The request endpointTimestamp : When the request was made
What's Saved
The complete request is saved including:
HTTP method and URL
All headers
URL parameters
Request body (JSON, form data, or text)
Body type selection
Privacy
History is stored locally in your browser only
No data is sent to external servers
History persists between browser sessions
You can clear history by clearing browser data