For Frontend & Backend Developers
Your precise tool for JSON data
Seamless Workflow from Editor to Validation
JSON-Werkstatt integrates directly into your existing development stack. Validate payloads, compare schemas, and transform structures without leaving your terminal or editor — cutting context-switching time by an estimated 40 minutes per day for teams processing API contracts daily.
The workflow begins the moment you open a .json or .jsonc file. JSON-Werkstatt reads the file, checks it against the nearest Draft-07 or Draft-2020-12 schema, and surfaces type mismatches, missing required keys, and enum violations inline. When you're ready to push, a single command-line invocation runs the full validation suite and exits with the appropriate status code — making it a natural fit for CI pipelines on GitHub Actions, GitLab CI, and Jenkins.
Inline Diagnostics in 12ms
Install the json-werkstatt-vscode extension (v3.2.1, 1.4 MB) from the Marketplace. It hooks into the language server protocol and reports errors as you type. Hover over any key to see its schema definition; click "Quick Fix" to auto-generate missing properties with default values from the schema's default field. Works with JSON, JSON5, and JSONC out of the box.
Zero-Config Pipeline Step
Run npx json-werkstatt validate --schema ./schemas/user.json ./payloads/*.json and get a structured report in SARIF, JSON, or human-readable text. Exit codes follow the convention: 0 for valid, 1 for validation errors, 2 for schema-parse failures. Add it to your pre-commit hooks or as a gate in your deployment pipeline to catch contract drift before it reaches production.
JSON Patch Generation
Compare two JSON documents and produce RFC 6902 compliant patch operations. The diff engine normalizes whitespace, reorders arrays by a configurable key path, and ignores null-vs-undefined distinctions — so you get meaningful diffs, not noise. Export the patch as a .json file you can apply with json-werkstatt apply-patch.
Browser Extension for Instant API Debugging
Inspect, validate, and transform API responses directly in your browser — no copy-pasting into external tools, no losing context mid-debug session.
The JSON-Werkstatt Browser Extension (available for Chrome 114+, Firefox 115+, and Edge 114+) intercepts XHR and fetch responses matching your configured URL patterns. When a response with Content-Type: application/json arrives, the extension parses it, validates it against any schema you've loaded, and overlays a lightweight badge on the Network tab showing pass/fail status at a glance.
One-Click Validation Badges
Each intercepted response gets a green or red badge next to its status code. Click the badge to expand a side panel showing the full validation report: which paths failed, expected vs. received types, and a diff against the schema's declared structure. The panel also includes a "Copy as cURL" button and a "Replay Request" option that re-sends the original request through a proxy for inspection.
Load Schemas from URLs or Files
Add schemas through the extension's popup panel — paste a JSON Schema directly, load from a local file, or point to a remote URL (e.g., https://api.example.com/.well-known/schema.json). The extension caches schemas for 24 hours and supports schema resolution via $ref pointers across up to 8 nested levels. Organize schemas into named collections like "Payment API v2" or "User Service — Staging".
Minify, Prettify, Filter Keys
Apply one or more transforms to any intercepted response before viewing it. Available operations include minification (strips whitespace, ~60% size reduction), prettification (2-space indent, sorted keys), key filtering (whitelist or blacklist paths like $.users[*].password), and type coercion (convert string timestamps to ISO 8601). Transforms are chainable and saved as named presets.
Capture & Export Debug Sessions
Start a recording session to capture all JSON responses over a 5-minute window. Export the session as a .jsonw file containing timestamps, request methods, URLs, status codes, full response bodies, and validation results. Share the file with teammates or attach it to a bug report in Jira or Linear. Sessions are stored locally — nothing leaves your machine unless you explicitly export.
The extension is open-source under the MIT license, with the source available at github.com/json-werkstatt/browser-extension. It currently has 12,400 active users and a 4.7-star rating on the Chrome Web Store.