Live Demo App: https://playground-api-demo.vercel.app/ API Docs & Portal: https://playground-api-xi.vercel.app/ GitHub Repository: https://github.com/nileshcodehub/playground_api Have you ever spent hours spinning up an Express server, writing Prisma schemas, running database migrations, and configuring CORS... just to build a frontend prototype or test a React UI?
Or worse—have you tried using traditional mock APIs like JSONPlaceholder, only to realize that every , , or request is a fake illusion that immediately disappears the second you refresh the page?
That exact frustration led me to create Playground API—a free, stateful mock REST & GraphQL API with per-session sandbox persistence.
To prove how powerful, stateful, and effortless it is, I built a production-grade Executive Directory & Data Console () using React 19 + Vite without writing a single line of backend or database code.
Check out the live interactive app here: https://playground-api-demo.vercel.app/ 🚀 🎨 What is "Directory Studio"? (The Demo App) Directory Studio is an enterprise-grade user management and data intelligence dashboard inspired by high-end fintech tools like Mercury, Ramp, and Stripe Sigma.
When you visit https://playground-api-demo.vercel.app/: You can create a new user profile (with avatar, contact info, company details, and location coordinates).
Refresh the page — your newly created user is still there!
Edit a user's company or email — the changes are persisted across page reloads.
Delete a user — the user is removed from your session view while other visitors still see the global baseline dataset intact! 💡 How Playground API Powers the Entire App (Under the Hood) Let's look at how ridiculously simple it is to build complex, production-grade applications using Playground API.
1.
Zero-Setup API Client No backend server, no database connection strings, no API keys required.
We just initialize standard requests:
2.
How Does State Persistence Work Without Logging In?
Playground API uses a smart Copy-on-Write Hybrid Overlay Engine: When you send a request with or pass , Playground API assigns you a unique HMAC-signed session identity: merges the 25 pristine global seed users with your private sandbox changes. saves your new record into your session sandbox. overlays your updated fields on top of seed record #1 for your browser only. hides record #1 from your queries without destroying it for other people on the internet.
3.
Rich Features Built in the React Demo A.
Full-Text Search with Typo-Tolerance & Debounce Typing into the search bar instantly filters records across names, handles, emails, and cities: B.
Slide-Over Inspector Sheet Clicking on any user opens a slide-over sheet with 3 tabs: Profile Details: Direct contact actions (, direct phone).
Company & Address: Organization catchphrase, location coordinates.
Live REST Payload: Raw JSON response directly from the Playground API endpoint with 1-click clipboard copy.
C.
Dual Presentation: Data Grid ⟷ Profile Cards Switch seamlessly between an Executive Data Grid and an Avatar Card Deck without re-fetching or reloading. 🚀 Why You Should Use Playground API for Your Next Project Whether you are a frontend engineer, mobile developer, educator, or QA lead, Playground API solves the biggest headache in prototyping: Use Case Why Playground API is the Best Choice 💼 Portfolio Projects Showcase real CRUD, search, pagination, and sorting in your React/Vue/Next.js portfolio apps without paying for or managing a backend database. ⚡ Frontend Prototyping Build full UI workflows before the backend team finishes their endpoints.
When the real API is ready, just swap the base URL! 🧪 E2E & Automated Testing Run deterministic Cypress, Playwright, or Vitest suites with isolated session tokens using the header. ⏱️ Simulating Edge Cases Test loading spinners and error screens by passing headers like or . 🌐 REST & GraphQL Parity Query the exact same persistent data via REST () or GraphQL Gateway (). 🛠️ Ready to