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Test API speed, validate contracts, compare responses, and improve software delivery and reliability.
Use this workflow to find performance and API tools for a production system. Start with latency or a contract check. Then inspect payloads, reliability targets, and delivery readiness. The tools help you separate network problems from application problems, check whether an API follows its contract, and decide which engineering action to take next. Most utilities run in the browser and provide a direct result without a sign-up. Review the privacy details on each tool page before you enter sensitive data.
17 free tools. Use the first tool that matches your current task.
Measure response time, Core Web Vitals, and inspect slow pages or APIs.
Measure global API response times. Visualize TTFB, DNS, and download speeds.
Calculate revenue lost from slow load times. See the business value of every 100ms improvement based on Deloitte benchmarks.
Detect heavy dependencies, deprecated packages, and bloat in your package.json.
Diagnose failing INP, LCP, CLS, and TBT bottlenecks with drop-in React and Next.js code refactors.
Set reliability targets, review delivery readiness, and architect server rendering & DB security.
Calculate error budgets and reliability targets. Know exactly when to freeze releases vs ship features.
Score your team on the four DORA metrics — deployment frequency, lead time, change failure rate, MTTR — and benchmark to Elite/High/Medium/Low.
Generate a production-grade CI pipeline checklist and GitHub Actions workflow in seconds.
Evaluate React Server Components, streaming SSR, edge runtime, and Server Actions for high-scale apps.
Design multi-tenant PostgreSQL Row-Level Security policies with generated SQL migrations and TypeScript types.
Validate schemas, compare responses, and create test payloads.
Validate essential OpenAPI 3 structure and format API contracts in your browser.
Compare structured API responses and spot added, removed, or changed fields.
Validate JSON data against a JSON Schema and see precise path-level errors.
Build curl commands, convert Postman collections, mock OpenAPI, and format GraphQL queries.
Build cURL commands, run API requests in your browser, format JSON responses, and compare changes locally.
Convert Postman JSON to cURL or reverse-engineer cURL back to Postman JSON. Run and inspect responses in your browser.
Generate realistic mock API responses from an OpenAPI schema locally.
Format GraphQL operations and catch common syntax errors in your browser.
Build readable GraphQL queries from fields, variables, and operation settings.