Fourteen free tools for testers

1. JSON Formatter & Validator

Paste JSON to format, minify or validate it. Invalid JSON shows the exact position of the problem.

2. JSON Compare

Compare an expected response with the actual one. You get the differences field by field – useful for API test failures.

3. Regex Tester

Test a regular expression against sample text. Matches and capture groups are listed below.

4. XPath & CSS Selector Generator

What it does: paste a piece of HTML, click any element in the preview, and get ready-to-use locators – id, data-testid, name, CSS and XPath (by attribute, by text, and absolute). You can also test your own locator below.

Test your own locator

5. Test Data Generator

What it does: creates realistic but fake rows you can use as test input. Tick the columns you need, choose how many rows, then copy or download as CSV / JSON. Nothing here is real personal data.

6. JWT Decoder

Decode the header and payload of a JSON Web Token and check its expiry. Decoding only – the signature is not verified, so never trust a token based on this alone.

7. Base64 Encoder / Decoder & Timestamp Converter

8. HTTP Status Code Reference

The codes you actually assert on in API tests. Search to filter.

9. XML Formatter & Validator

Format SOAP requests and XML payloads, and check whether they are well-formed.

10. API Response Formatter

Paste an API response and get every field as a path with its value – copy them straight into your assertions.

11. Random Data Generator

UUIDs, random strings, numbers, dates and emails for quick test input.

12. Password / Test Credential Generator

Passwords that pass typical policy rules – useful for registration and login test data.

For test accounts only – do not use these for production or personal accounts.

13. SQL Query Generator

What it does: fill in the table and columns and the query is written for you – the queries testers need most for data validation. The query updates as you type.

14. AI Test Case Prompt Generator

Fill in your feature details and this builds a complete, structured prompt. Copy it into ChatGPT, Claude or Gemini to get test cases – then review them yourself before using them.