JSON schema validator
Paste a JSON document and a JSON Schema to check whether the data conforms to the expected structure, types, and constraints. Runs entirely in your browser — nothing is sent to a server.
What is JSON Schema validation?
JSON Schema is a vocabulary for annotating and validating JSON documents. It lets you describe the expected structure of your data — which fields are required, what types they should be, and what constraints they must satisfy — then validate any JSON document against that description. Schema validation catches structural problems like missing fields, wrong types, out-of-range values, and malformed strings before they cause bugs downstream.
When to validate against a schema
- Validating API request and response payloads
- Testing webhook payloads before integration
- Checking configuration files match expected formats
- Verifying data pipeline outputs
- Documenting and enforcing data contracts between teams
JSON syntax validation vs. schema validation
Syntax validation checks whether a string is valid JSON at all — are the braces matched, are strings quoted, are commas in the right places? Schema validation goes a step further: given that the JSON is syntactically valid, does it also conform to a specific structure with the right fields, types, formats, and constraints? If you only need to check syntax, the JSON validator is the right tool. If you need to verify structure, use this schema validator.
From validated data to instant insights
If you're working with structured data for analytics or reporting, Basedash can skip the manual validation entirely. Describe the chart or metric you want in plain English, and Basedash writes the query, runs it against your actual data, and renders the visualization — all in seconds. It connects to PostgreSQL, MySQL, BigQuery, Snowflake, and 750+ other data sources.
FAQ
Which JSON Schema drafts are supported?
This tool supports JSON Schema Draft 2020-12, Draft 2019-09, Draft-07, Draft-06, and Draft-04. It automatically detects the draft from the $schema keyword in your schema.
Is my data stored or sent to a server?
No. All validation runs entirely in your browser using JavaScript. Your data and schema are never transmitted, logged, or stored anywhere.
What error details are shown?
Each validation error includes the JSON path that failed (e.g., /address/zip), the schema keyword that was violated (e.g., pattern), and a human-readable description of what went wrong.
Can it validate nested objects and arrays?
Yes. The validator recursively checks every level of nesting in your JSON against the corresponding schema definitions, including nested objects, arrays, and array items.
What's the difference between this and the JSON validator?
The JSON validator checks syntax — is this valid JSON? This tool checks structure — does this valid JSON conform to a specific schema that defines required fields, types, formats, and constraints?
Does it support custom formats?
The tool supports standard JSON Schema formats like email, uri, date-time, and uuid. Custom format validators are not supported in this browser-based version.
Skip the validation — let AI handle your data
Connect your data and describe what you want to see. Basedash handles the query, visualization, and dashboard.