Practical guides on testing modern APIs — REST, GraphQL, SOAP, OAuth2, Swagger and OpenAPI. Every post links to a live free public endpoint you can practice on while reading.
Step-by-step guide to testing a REST API in Postman: import an OpenAPI spec, send your first GET, build a save-token script, and chain requests with collection runner. Free public endpoints to practice on.
2026-01-15 · 7 min readLearn GraphQL in 15 minutes against a real public endpoint. Queries, mutations, variables, fragments, error handling and authentication — with copy-paste examples for fetch, curl and GraphiQL.
2026-01-22 · 8 min readYes, SOAP is still everywhere in enterprise. This tutorial shows how to call a real public SOAP API — envelope structure, WSDL import, SoapUI walkthrough, and how to generate a typed client in Java, .NET and Python.
2026-02-02 · 7 min readA practical OAuth2 tutorial against a live public sandbox: client-credentials flow, JWT decoding, refresh-token rotation, role-based access and how to negative-test 401 vs 403.
2026-02-09 · 8 min readHand-picked free public APIs for testing in 2026: JSONPlaceholder, ReqRes, DummyJSON, Postman Echo, Beeceptor, TotalShiftLeft and more. What each is best at and where each falls short.
2026-02-18 · 10 min readHonest comparison of the three popular OpenAPI doc renderers — Swagger UI, Redoc and Stoplight Elements. Try-it-out, performance, customisation, hosting cost and when each one wins.
2026-02-26 · 6 min readA practical, opinionated decision guide for picking REST, GraphQL or SOAP — with a free sandbox where you can try the same data behind all three protocols.
2026-03-04 · 9 min readA practical 30-point API testing checklist covering happy path, schema, auth, errors, performance, security and observability. Each item links to a sandbox endpoint where you can practice.
2026-03-12 · 8 min readYes. Free to read, free to share, no signup, no paywall.
Yes. Every code sample runs against the free TotalShiftLeft public API sandbox — no API key, no signup.
Open the live sandbox — REST, GraphQL, SOAP and auth in one place. No signup, no API key.
Open the API Sandbox →Topics: API testing tutorials · Postman tutorials · OAuth2 guides · Swagger and OpenAPI guides · QA automation playbooks