API Payload Validator
Validate JSON API request and response payloads against OpenAPI schemas directly in your browser.
Request & Response Validation
Validate JSON request bodies and response payloads against selected OpenAPI operations and schemas.
Field-Level Errors
Review missing fields, type mismatches, enum issues, array item errors, and nested object validation results.
OpenAPI-Aware Selection
Choose a path, method, request body, or response status code from the loaded OpenAPI document.
Local Processing
API payloads and schemas are processed in your browser during normal use and are not intentionally transmitted to ${Brand.name} servers.
Paste an OpenAPI schema and JSON payload or load an example to begin.
By using this free tool, you agree to the Efneze Terms of Use and Privacy Policy. Processing runs in your browser during normal use. Avoid pasting sensitive, production, credential, token, PHI, or confidential data unless permitted by your organization's policies.
JSON OpenAPI documents are supported in this version. YAML support may be added later.
API Validator
POST /orders
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Browser tools process data locally in your browser runtime. Avoid submitting sensitive information or PHI.
Validate API Payloads Before Debugging, Testing, and Integration Work
API request and response payloads can be difficult to review when schemas, required fields, nested arrays, enums, and object structures are spread across an OpenAPI document. An API payload validator helps developers, QA teams, and integration teams compare JSON payloads against selected OpenAPI request or response schemas before debugging, documenting, or sharing examples.
This tool is designed for quick browser-based inspection: load an OpenAPI document, select an endpoint and method, choose a request or response schema, validate a JSON payload, and review field-level errors without sending test requests or connecting to an API.
Common API Payload Validator Use Cases
API contract review
Check whether example request and response payloads match the expected OpenAPI schema before sharing them.
QA testing
Validate sample payloads during manual testing, regression checks, or API documentation review.
Integration debugging
Compare payloads from logs, mock services, or integration tests against the expected request or response shape.
Developer documentation
Clean up and verify JSON examples before adding them to API docs, tickets, runbooks, or support notes.
OpenAPI-Aware Checks and Validation Limits
The validator can help identify missing required fields, type mismatches, enum issues, array item problems, numeric bounds, string length issues, and common nested object errors. These checks are informational and are not a replacement for full OpenAPI compliance testing, contract testing, production validation, live API testing, or review in the target application environment.
Related Developer and Data Tools
API payload validation often sits alongside JSON formatting, XML inspection, SQL debugging, and flat-file review. Use the JSON Viewer to inspect nested JSON payloads, the XML Viewer to inspect XML documents, the SQL Formatter to clean up query text, and the Flat File Viewer to inspect CSV, TSV, and pipe-delimited files, and the HTTP Request Inspector to parse raw HTTP requests, with $Forge for planned local desktop data inspection workflows.
Frequently Asked Questions
What is an API payload validator?
An API payload validator compares a JSON request or response payload against an expected schema, such as a schema defined in an OpenAPI document. It helps identify missing fields, type mismatches, enum issues, and nested object or array problems.
Can I validate JSON against an OpenAPI schema online?
Yes. Paste an OpenAPI document and a JSON payload, select the endpoint and request or response schema, and review validation results directly in your browser.
Does this tool send API requests?
No. This tool validates pasted JSON payloads against OpenAPI schema definitions. It does not send API requests, call endpoints, connect to APIs, or create webhook URLs.
Does this tool fully validate OpenAPI documents?
No. The tool focuses on validating JSON payloads against selected OpenAPI schemas. It is not a full OpenAPI specification validator and does not replace contract testing, API gateway validation, or testing in your target application environment.
Is API payload input uploaded to ${SiteConfig.brand.name} servers?
The validator processes API payloads and schemas in the browser during normal use, and tool input is not intentionally transmitted to ${SiteConfig.brand.name} servers. Teams should still avoid pasting production payloads, OpenAPI specs with internal URLs, credentials, tokens, secrets, connection strings, PHI, or sensitive data unless permitted by their organization's policies.
Does this tool support YAML OpenAPI files?
This version is focused on JSON OpenAPI documents. YAML support may be added later.
Who uses API payload validators?
Developers, QA engineers, data engineers, integration teams, API support teams, and technical writers use API payload validators to review request and response examples, debug integrations, and check API documentation samples.