Online GraphQL Schema Validator

The Online GraphQL Schema Validator validates GraphQL SDL for correctness and consistency. It accepts raw SDL text or files, runs syntax checks, and confirms that all referenced types, fields, interfaces, and directives exist according to the GraphQL specification. This reduces runtime surprises and helps teams maintain stable API contracts.

Conceptually, the tool builds an AST from the SDL, applies GraphQL validation rules, and emits a detailed diagnostic list with locations. Users include API developers, backend engineers, QA analysts, and DevOps practitioners who integrate schema validation into design, review, and deployment workflows.

Value and differentiators: fast feedback in CI, batch validation across several schemas, detailed error messages with line and column, and the ability to export results as JSON or CSV for issue trackers. Core features include syntax validation, type validation (checking for undefined types and invalid references), directive validation, and schema composition checks; optional features include version-to-version compatibility, delta reporting, and export options.

This tool focuses on static validation and compatibility, enabling teams to catch issues early and maintain API integrity across releases.