URL Encoder for API Requests vs JSON Formatter for Response Debugging

Q: Why does my API return 400 Bad Request?

Often caused by unencoded special characters in URL parameters. Characters like &, =, ?, #, and spaces break URL parsing. Use URL Encoder to percent-encode your parameters before sending the request.

Q: How do I debug a malformed API response?

Paste the raw response into JSON Formatter. If it fails to parse, you will see the exact error location (missing comma, unclosed bracket, etc.). If it parses, the formatted view helps you inspect the data structure for logical issues.

Q: Should I encode the entire URL or just parameters?

Only encode parameter VALUES, not the URL structure itself. Do not encode ?, &, = that separate parameters — only encode special characters within parameter values. URL Encoder handles this when you paste individual parameter values.

Q: How do I use these tools with cURL?

For requests: URL-encode parameters, then build your cURL command. For responses: copy the response text and paste into JSON Formatter. Example: curl -s api.example.com/search?q=encoded_query and then format the output.

Overview

URL Encoder for API Requests

Percent-encodes parameters for REST API requests — encoding query strings, path parameters, and form data so they are transmitted correctly. Prevents API errors caused by special characters in user input, search queries, and filter parameters.

Best for:

✓ Encoding search queries for API GET requests
✓ Building OAuth callback URLs with encoded redirect URIs
✓ Encoding filter parameters with special characters (>, <, &)
✓ Debugging API 400 errors caused by unencoded parameters

JSON Formatter for Response Debugging

Pretty-prints and validates API response JSON — transforming minified single-line responses into readable, indented format with syntax highlighting. Quickly identifies missing fields, wrong types, and structure issues in API integrations.

Best for:

✓ Pretty-printing minified API responses for visual inspection
✓ Validating JSON response structure matches API documentation
✓ Debugging unexpected null or missing fields in responses
✓ Comparing actual vs expected API response schemas

Feature Comparison

Feature	URL Encoder for API Requests	JSON Formatter for Response Debugging
API workflow stage	Request construction (before sending)	Response analysis (after receiving)
Direction	Encode text to URL-safe format	Format JSON to readable structure
Error prevention	Prevents 400 Bad Request from malformed URLs	Catches invalid JSON in responses
Debugging use	Fix invalid parameter API errors	Understand API response structure
Input format	Plain text with special characters	Raw JSON string
Output format	Percent-encoded safe string	Indented, highlighted JSON
Works with cURL	Encode params for cURL commands	Format cURL JSON output
Works offline	Yes — client-side	Yes — client-side

Real Usage Examples

URL Encoder for API Requests

Input

q=price > 100 & category=tools

Output

q=price%20%3E%20100%20%26%20category%3Dtools

JSON Formatter for Response Debugging

Input

{"data":{"users":[{"id":1,"status":"active"},{"id":2,"status":null}]},"meta":{"total":2}}

Output

{
  "data": {
    "users": [
      {"id": 1, "status": "active"},
      {"id": 2, "status": null}
    ]
  },
  "meta": {"total": 2}
}

When to Use Each Tool

Use URL Encoder for API Requests when...

Use URL Encoder BEFORE sending an API request — encoding query parameters, path segments, and form data that contain special characters. This prevents 400 Bad Request errors and ensures the API receives the intended values.

Use JSON Formatter for Response Debugging when...

Use JSON Formatter AFTER receiving an API response — pretty-printing the minified JSON to understand the response structure, validate the schema, and identify issues like null values, missing fields, or unexpected types.

Use both together when...

Complete API debugging cycle: URL-encode your request parameters (fixing request-side issues), send the request, then format the JSON response (understanding response-side data). Both tools cover the full request-response lifecycle.

Try Both Tools Free

Both tools run entirely in your browser — no signup, no data collection, no limits.

Open URL Encoder for API Requests Open JSON Formatter for Response Debugging

Frequently Asked Questions

Why does my API return 400 Bad Request?

Often caused by unencoded special characters in URL parameters. Characters like &, =, ?, #, and spaces break URL parsing. Use URL Encoder to percent-encode your parameters before sending the request.

How do I debug a malformed API response?

Paste the raw response into JSON Formatter. If it fails to parse, you will see the exact error location (missing comma, unclosed bracket, etc.). If it parses, the formatted view helps you inspect the data structure for logical issues.

Should I encode the entire URL or just parameters?

Only encode parameter VALUES, not the URL structure itself. Do not encode ?, &, = that separate parameters — only encode special characters within parameter values. URL Encoder handles this when you paste individual parameter values.

How do I use these tools with cURL?

For requests: URL-encode parameters, then build your cURL command. For responses: copy the response text and paste into JSON Formatter. Example: curl -s api.example.com/search?q=encoded_query and then format the output.