GLOBAL #1 INTERACTIVE API LEARNING PLATFORM & LIVE API LABS

The Premier API Learning Platform with Hands-On API Labs

Welcome to Endpoint Lab, the premier global interactive API learning platform and hands-on API lab environment. Master API learning by calling real HTTP requests in live sandboxes. Whether you are looking for an interactive API lab, comprehensive API learning labs, or practical hands-on API practice sandboxes, our platform takes you from REST API fundamentals to advanced production resilience. Learn REST APIs, HTTP protocol methods, headers, authentication, and API security from scratch, and earn an employer-verifiable certification.

Start learning free Browse curriculum roadmap
  • 4 career tracks
  • 6 client projects
  • 12 guided missions
  • 12 live API worlds
Mission 07 · Checkout, retry, deliver
POST /v1/mock/payments
Idempotency-Key: order-1042
{"order_id":"ord_8f2","amount_cents":4800}

HTTP/1.1 201 Created
idempotency-replayed: false

POST /v1/mock/payments      ← retry after timeout
Idempotency-Key: order-1042

HTTP/1.1 201 Created
idempotency-replayed: true   ✓ charged once
Objective verified by the server
NEW TO APIS?

You already use APIs every day

When a weather app shows today’s forecast, a payment app confirms your transfer, or a delivery app shows where your order is, that app is asking another computer for information. The rules for asking are called an API. Think of a restaurant: you order from the waiter, the kitchen cooks, and the waiter brings your food. The app is you, the API is the waiter, and the server is the kitchen.

  • Every new word is explained the first time you see it
  • Your first real request takes about five minutes
  • A safe sandbox: nothing you do affects real systems
  • Grow at your own pace into projects and certification
Start beginner API labs
FREE TOOLS, NO SIGN-UP

Use the tools professionals use, while you learn

  • App Builder

    Create a real API without code, drag together a live app, and call it from your own computer. Every screen updates instantly.

  • Endpoint Client

    A full API client in your browser. Every response is explained in plain language and checked against the OWASP API Security Top 10.

  • DNSSEC & Resilience Audit

    Real-time cryptographic DNSSEC chain validation (Ed25519/ECDSA), resolver latency metrics, and Prometheus exporter.

  • API readiness audit

    Grade an OpenAPI spec for design, security and AI-agent readiness, and export it as MCP tools.

  • JWT security checker

    Decode tokens and catch weak signing secrets, missing expiry and leaked personal data.

  • HTTP Status Codes

    Every status code and header, with what to do next and when to retry.

HOW IT WORKS

A path that adapts to you

  1. Tell us where you are

    Pick your role and experience, then take an 8-question placement check. You skip the lessons you already know.

  2. Learn by sending real requests

    Every lesson has a live sandbox. Create, break and repair real resources; the server checks your work, not your clicks.

  3. Unlock modules by score

    Each of 8 modules ends with a test you pass at 80%. Fresh questions on every retake, with explanations for what you missed.

  4. Earn a credential that verifies itself

    Pass the timed exam and practical missions. Your signed certificate carries a QR code any employer can check in seconds.

CAREER TRACKS

Pick the job you want. Follow a clear roadmap.

API Integration Developer

Frontend, mobile or full-stack developer who connects products to third-party services

Integrate any documented API reliably: authenticate, page through data, write safely with idempotency, and recover from rate limits, timeouts and outages.

  1. Speak HTTP · Read and send requests with confidence.
  2. Shape data · Send valid payloads and read complete collections.
  3. Write safely · Make writes that survive retries and bad networks.
  4. Integrate for real · Deliver client projects end to end.
  5. Get certified · Prove it to employers.
Backend API Developer

Engineer who designs and operates the APIs other teams depend on

Design contracts that clients can trust: correct status codes, validation, concurrency control, versioning and safe state transitions.

  1. Foundations · Master HTTP semantics from the server side.
  2. Protect data · Secure access and prevent lost updates.
  3. Design for failure · Make failure explicit and recoverable.
  4. Ship real systems · Deliver production-shaped projects.
  5. Get certified · Prove it to employers.
API Test Engineer

QA or SDET who signs off API releases

Write positive and negative API tests, verify contracts and concurrency rules, and produce release evidence a manager can sign off.

  1. Foundations · Understand what a correct response looks like.
  2. Break it on purpose · Find what the contract rejects.
  3. Test the hard parts · Concurrency, idempotency and failure.
  4. Release evidence · Deliver test evidence for real releases.
  5. Get certified · Prove it to employers.
API Security Engineer

Engineer who designs, reviews and tests APIs so data stays protected

Threat-model an API, prevent the OWASP API Top 10 risks, secure tokens and integrations, and build security testing and monitoring into delivery.

  1. API fundamentals · Know how requests, responses and authentication work.
  2. Security foundations · Threat modeling, HTTPS, access control basics and secret hygiene.
  3. The common risks · Prevent the access-control and abuse problems behind most incidents.
  4. Production security · Tokens, integrations, configuration, monitoring and secure delivery.
  5. Get certified · Earn the API Security certificate, then the integration credential.
REAL PROJECTS

Build what companies actually need

Each project is a client brief from a real industry. You get acceptance criteria and one starter request, then design the integration yourself. The server checks every criterion, including how you handle outages, rate limits and retries. Verified projects go on a public portfolio employers can trust.

FINTECH
Invoice payments without double charges

Issue invoices, collect payment exactly once through retries, reject invalid transitions and refund correctly while the payment service has an outage.

Ledgerly, a subscription billing startup · about 3 h · advanced
LOGISTICS
Shipment tracking with safe concurrent edits

Book shipments with unique references, prevent lost updates with ETags, move them through transit and page through the carrier list.

A freight forwarder integrating with a carrier · about 3 h · advanced
HEALTHCARE
Appointment booking that never double-books

Book slots with uniqueness rules, retry bookings idempotently, check patients in, cancel correctly and survive a gateway timeout.

A multi-doctor clinic · about 2 h · intermediate
E-COMMERCE
Catalog sync that survives an API change

Sync products across two resources, page through the catalog, update stock safely and adapt when the provider changes its response shape.

A marketplace seller syncing a catalog · about 3 h · advanced
SAAS
Support ticket workflow with expiring credentials

Run tickets through a strict workflow, attach comments across two resources, refuse invalid transitions and recover from an expired session.

A B2B software company · about 2 h · intermediate
QUALITY ENGINEERING
Contract test suite for a user directory

Prove a user-directory contract with positive and negative tests: validation, uniqueness, missing records, disabled methods and method discovery.

An HR platform before a release · about 2 h · intermediate
CURRICULUM

Eight domains, from fundamentals to production

  1. 01
    API foundations

    Explain the client/server request–response model

  2. 02
    Resources & methods

    Choose correct HTTP methods and their safety/idempotency guarantees

  3. 03
    Parameters & payloads

    Shape requests with parameters, JSON bodies, validation and pagination

  4. 04
    Authentication & security

    Apply authentication, authorization, OAuth scopes and secret handling

  5. 05
    Errors & resilience

    Design timeouts, retries, rate-limit handling and idempotent writes

  6. 06
    Integration patterns

    Integrate with SDKs, webhooks, polling, streams, REST and GraphQL

  7. 07
    Contracts & testing

    Use OpenAPI contracts, negative tests, versioning and observability

  8. 08
    Integration capstone

    Operate an end-to-end resource lifecycle across control and data planes

Plus a 14-lesson API Security course, from threat modeling to the OWASP API Security Top 10, token security and secure delivery. Also included: protocol labs for multipart uploads, signed webhooks, SSE and GraphQL; an API designer that turns your schema into a working API; workflow replay; and OpenAPI import with change-impact analysis.

THE CREDENTIAL

Certified API Integration Practitioner

  • Timed 45-minute exam from a protected question pool
  • At least 75% overall and 50% in every domain
  • Three hands-on missions verified by the server
  • Ed25519-signed, with public QR verification and revocation
  • Exports as an Open Badges 3.0 credential and to LinkedIn
  • Valid for two years, with recertification
How verification works
SAMPLEEndpoint Lab by StellerSight Private LimitedAlex ExampleCertified API Integration PractitionerMerit · 88%
EL-XXXX-XXXX-XXXX-XXXX
FREE ACCESS

Everything is free. No card, no trial, no catch.

  • All 32 lessons and knowledge checks
  • 12 guided missions and 6 real client projects
  • Live sandboxes, API worlds and protocol labs
  • Career roadmaps and a verified public portfolio
  • All 8 module tests and the certification exam
  • Signed, QR-verifiable certificate and Open Badge
  • Classrooms for instructors and teams

Endpoint Lab is free while we build it with our first learners. Sign in and start. Your progress, projects and certificates are yours to keep.

Get started with free access

Built for teams and instructors

Create a classroom, assign missions or your own lab blueprints, and review each learner's server-verified evidence. Every learner works in an isolated sandbox, so no one can see or break anyone else's data.

QUESTIONS

Frequently asked questions

Is this an accredited qualification?

It is an independent professional credential issued by StellerSight through Endpoint Lab. It is not a university degree or a government accreditation. Its value comes from a demanding, server-verified assessment that employers can check directly.

How does an employer verify my certificate?

Scan the QR code or enter the credential ID at the verification page. It shows whether the certificate is valid, expired or revoked, and confirms its cryptographic signature. You can also download it as an Open Badges 3.0 credential.

How long does it take?

Most learners finish in 8 to 20 hours. Your profile and placement produce a personal forecast based on the hours you can study each week.

What if I fail a test?

Review the explanations and retake it after a short cooldown with different questions. Exam retakes have a 24-hour cooldown and a limit of three per 30 days.

How long is the certificate valid?

Two years. Recertification opens 90 days before it expires, so your credential reflects current practice.

Do I need to install anything?

No. The sandbox, API worlds and tools run in your browser. You can also call the practice APIs from curl, Postman or your own code with a scoped key.

Can my company train a whole team?

Yes. Instructors create classrooms, assign missions, review verified submissions and give feedback. It is free for teams too.

Is it really free?

Yes. Every lesson, mission, project, module test, the certification exam and the certificate are free. No payment details are requested. Certificates you earn stay valid for their full term.

Your first verified request takes five minutes.

Start your first request free