OpenAPI Spec Validator — Swagger Compliance Checker
Validate OpenAPI 2.0 (Swagger) and OpenAPI 3.0/3.1 specification files for compliance, missing required fields, unresolved $ref paths, and schema errors. Paste JSON or YAML or upload a file — errors and warnings are listed by path with severity levels and actionable fix suggestions. All validation runs entirely in your browser.
How to Use OpenAPI Spec Validator — Swagger Compliance Checker
How to Use the OpenAPI Spec Validator
Step 1: Paste or Upload Your Spec
Paste your OpenAPI or Swagger specification directly into the textarea, or click Upload to load a .json, .yaml, or .yml file from your computer. Both JSON and YAML formats are fully supported.
Step 2: Load an Example (optional)
Click one of the example buttons to load a pre-built spec:
- Minimal 3.0 — the smallest valid OpenAPI 3.0 spec
- Petstore 3.0 — a complete API with schemas, parameters, and request bodies
- Swagger 2.0 — a Swagger 2.0 spec with definitions and path parameters
- With Errors — an intentionally broken spec showing common mistakes
Step 3: Click Validate Spec
Click Validate Spec to run validation. Results appear immediately in the right panel.
Step 4: Review the Status and Stats
The status card shows whether the spec is valid (green) or invalid (red). The stats grid shows the detected version (Swagger 2.0, OpenAPI 3.0, or 3.1), the number of paths, operations, and schemas defined, plus the total error and warning counts.
Step 5: Fix Issues
The Issues panel lists each error and warning with:
- Path — the JSON path inside the document where the issue was found (e.g.,
#/paths/users/get/responses) - Message — a plain-English description of the problem
- Fix suggestion — a specific action you can take to resolve it
Errors (red) indicate spec non-compliance. Warnings (amber) are best-practice recommendations that do not prevent the spec from being technically valid.
What the Validator Checks
- Version field —
openapi(3.x) orswagger(2.x) must be present at the root - info object —
titleandversionare required;descriptionis recommended - paths object — must be present; each path must start with
/ - Operations — each must have a
responsesobject with at least one entry - Parameters — must include
nameandinwith valid values; path parameters must match the URL template - $ref resolution — all internal
$refvalues must point to paths that exist in the document - Security — if root
securityis set, the corresponding scheme definitions must exist - Best practices —
operationId,summary/description,requestBodyfor POST/PUT/PATCH, and 2xx responses
Limitations
This is a structural validator based on the OpenAPI specification rules. It does not execute a full JSON Schema validation of property values, does not check external $ref URLs, and does not validate discriminator or oneOf/anyOf semantics. For full compliance testing, use the validator as a first pass and follow up with an official OpenAPI library in your build pipeline.
Frequently Asked Questions
Most Viewed Tools
Screen Size Converter — Diagonal Dimension Tool
Calculate screen width and height from diagonal size and aspect ratio. Convert between inches and centimeters for displays, TVs, and monitors with instant dimension calculations.
Use Tool →DPI Calculator — Print Resolution Tool
Calculate DPI (dots per inch), image dimensions, and print sizes. Convert between pixels and physical dimensions for printing and displays.
Use Tool →Seconds to Time Converter — HH:MM:SS Formatter
Convert seconds to HH:MM:SS time format instantly with precise calculations and easy-to-read formatting.
Use Tool →TOTP Code Generator — 2FA Testing Tool
Generate time-based one-time passwords from a TOTP secret key. Enter your base32 secret, choose a period and digit length, and get the current and next codes with a live countdown timer. Useful for testing and debugging 2FA integrations.
Use Tool →Password Entropy Calculator — Crack Time Estimator
Calculate the information-theoretic bit entropy of any password or API key. Detects character set pools automatically, shows the total number of possible combinations, and estimates crack time across five attack scenarios from rate-limited web logins to GPU cracking clusters.
Use Tool →JSONL Formatter — Line-by-Line Validator
Format, validate, and inspect JSON Lines (JSONL) and NDJSON files. Validates each line individually, reports parse errors by line number, outputs compact JSONL or a pretty-print preview, and lets you download the cleaned file.
Use Tool →JSON to Zod — Schema Generator
Generate Zod validation schema code from a JSON sample object. Infers z.string(), z.number(), z.boolean(), z.array(), z.object(), and z.null() types automatically. Handles nested objects, arrays of objects with optional field detection, and outputs copy-ready TypeScript with import and z.infer type alias.
Use Tool →TLS Cipher Suite Checker — Strength Analyzer
Check TLS protocol version compatibility and cipher suite strength ratings against current best practices. Supports IANA and OpenSSL cipher names — rates each suite as Strong, Weak, or Deprecated and explains why.
Use Tool →Related API & Backend Tools
GraphQL Query Formatter — Mutation & Subscription Tool
Format and prettify GraphQL queries, mutations, subscriptions, and fragments with correct indentation.
Use Tool →API Gateway Rate Limiting Calculator — Model RPS, Burst, and Token Buckets
Calculate token bucket size and refill rate from RPS targets for API gateway throttling. Enter your steady-state requests per second, burst multiplier, and average response time — the calculator outputs the bucket capacity, refill rate, per-minute and per-hour quotas, and concurrent connection estimate. Generates ready-to-paste throttling config for AWS API Gateway, Kong, and Nginx. Free and runs entirely in your browser.
Use Tool →GraphQL Variables Formatter — Query Validator
Format and validate GraphQL query variables JSON for use in queries and API clients. Paste your variables JSON alongside a GraphQL query to instantly format the JSON, validate that each variable matches its declared type, catch missing required variables, and highlight undeclared extras.
Use Tool →API Latency Budget Calculator — Plan Distributed System Performance
Set a P99 SLO latency target and distribute the budget across your upstream service dependencies. See remaining headroom, utilization percentage, a stacked allocation bar, and a per-service breakdown with optional P99 actual measurements.
Use Tool →GraphQL Subscription Builder — Generate WebSocket Payloads and Client Queries
Build GraphQL subscription query strings and generate WebSocket connection code snippets for Apollo Client, urql, and graphql-ws. Define your operation name, variables, and selection fields visually, then copy the ready-to-use code.
Use Tool →GraphQL Cost Estimator — Analyze Query Complexity and Depth
Assign custom field weights to a GraphQL schema and calculate the total query complexity score. Paste any GraphQL query, configure per-field costs, and get a per-field breakdown table showing depth, multipliers, and cumulative cost.
Use Tool →OAuth Token Validator — JWT & OIDC Decoder
Validate and inspect OAuth tokens in your browser. Decode JWT access tokens and ID tokens to view claims, scopes, and expiry. Analyse opaque tokens for entropy and format. Free and private.
Use Tool →CORS Header Generator — Cross-Origin Config Tool
Build CORS configuration headers interactively for web servers and APIs. Set allowed origins, methods, request headers, credentials, and preflight cache duration — then copy the generated Access-Control headers or ready-to-paste code snippets for nginx, Express.js, Flask, and .NET.
Use Tool →Share Your Feedback
Help us improve this tool by sharing your experience