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AUTOMATION SNIPPET HUB

API Assertion Generator

Paste your JSON on the left to generate assertions instantly. No limits, secure, and ready for Rest-Assured or Postman.

JSON Response Body
Generated Assertions

Assertion Best Practices

Effective API testing requires validating both the structure and the values of a response. Below are key assertion types:

equalTo()Validates that the specific field matches an expected value exactly.
hasSize()Ensures an array contains the expected number of items.
notNullValue()Confirms that a mandatory field is present and not empty.
instanceOf()Verifies the data type (e.g., Integer, String, Boolean).

About the Software Testers Hub Assertion Generator

Writing validation logic for nested JSON objects is the most time-consuming part of API Automation. Our Assertion Generator automates this process by parsing your response body and creating syntactically correct code for Rest-Assured and Postman.

Boost Your SDET Productivity

Whether you are a manual tester transitioning to automation or an experienced SDET, this tool eliminates syntax errors. Simply paste your response from tools like Rest-Assured or Playwright and get your assertions in one click. If you are preparing for technical interviews, combine this with our JSONPath Evaluator to master data extraction and validation.

Secure and Private

Security is our priority. Since this tool operates client-side, your sensitive API responses never leave your machine. We do not store any data, making it compliant with professional data privacy standards. This architecture also allows us to offer unlimited access to our community of 50,000+ testers.

Pro Tip: After generating your assertions, run your full suite and log results using our Reporting Hub or perform a Scenario Audit for better coverage.