Who This Roadmap Is For

This roadmap is ideal for:

  • Software Testers expanding into API Testing.
  • UI Automation Engineers adding backend validation skills.
  • Anyone preparing for SDET or API Automation interviews.
  • Duration: Approximately 8–10 weeks
  • Study Time: 1–2 hours per day
  • Learners with a strong Java background can progress more quickly through the REST Assured stages.

Why API Testing Matters

API testing is:

  • Faster than UI automation
  • More stable and reliable
  • Easier to automate
  • Better at identifying backend defects early

Modern SDET roles expect proficiency in both UI and API automation.

Advertisement

Stage 1 — API Concepts (Weeks 1–2)

Why Start with Concepts?

Learning how to send requests in Postman is not enough.

Strong API testers understand HTTP, REST principles, authentication, and status codes—topics that frequently appear during interviews.

Topic Tutorials
API Fundamentals, REST vs SOAP, Client-Server Architecture API Testing Fundamentals
HTTP Methods, Status Codes & Idempotency HTTP Methods & Status Codes
Requests, Responses, Headers & Parameters HTTP Requests & Responses
JSON, XML & Schema Basics API Data Formats

Stage 1 Milestone

Be able to explain confidently:

  • HTTP Status Code 401 vs 403
  • PUT vs PATCH
  • Idempotent HTTP methods

Recommended Companion Guide: HTTP Status Codes Cheat Sheet

Stage 2 — Postman (Weeks 3–4)

Why Postman?

Postman is the fastest way to begin hands-on API testing before moving into automation.

Topic Tutorials
Workspaces, Collections, Environments & Variables Postman Essentials
Tests Tab, Assertions & Request Chaining Postman Scripting
Authentication (Basic, Bearer, OAuth 2.0 & JWT) API Authentication
Hands-on Exercises Postman Practical Roadmap

Progress through these APIs in order:

  • RESTful Booker
  • ReqRes
  • FakeStore

Stage 2 Milestone

Build a complete end-to-end Postman workflow:

Login
   ↓
Generate Token
   ↓
Create Resource
   ↓
Retrieve Resource
   ↓
Update Resource
   ↓
Delete Resource
   ↓
Verify 404 Response

Recommended Companion Guide: Postman Cheat Sheet

Stage 3 — REST Assured (Weeks 5–7)

Why REST Assured?

REST Assured transforms manual API validation into scalable Java-based automation.

Prerequisite

A solid understanding of Java fundamentals is recommended before beginning this stage.

Topic Tutorials
Project Setup, Maven & Given-When-Then REST Assured Setup & Syntax
HTTP Requests, Parameters & Headers Sending Requests
Response Validation & Hamcrest Response Validation
JsonPath Extraction & API Chaining Logging & Extraction
POJO Serialization Serialization & POJO
Authentication & Token Handling REST Assured Authentication
Practical Exercises REST Assured Practical Roadmap

Stage 3 Milestone

Rebuild the same Postman workflow using:

  • Java
  • REST Assured
  • TestNG

Recommended Companion Guide: REST Assured Cheat Sheet

Stage 4 — Framework & Quality (Weeks 8–9)

Why Framework Development?

Interviewers expect reusable API automation frameworks—not isolated test scripts.

Topic Tutorials
Request & Response Specifications REST Assured Framework Design
TestNG Integration & Data-Driven Testing TestNG Integration
JSON Schema Validation JSON Schema Validation
Negative Testing & Error Handling Negative Testing
API Security Basics API Security Testing

Stage 4 Milestone

Publish an API Automation Framework on GitHub including:

  • Request & Response Specifications
  • POJO Models
  • Configuration Management
  • Environment Switching
  • JSON Schema Validation
  • TestNG Integration

Stage 5 — CI/CD & Ownership (Week 10)

Moving Toward Senior-Level Automation

The final stage focuses on integrating API automation into CI/CD pipelines and production-ready workflows.

Topic Tutorials
Newman, Jenkins & Reporting API CI/CD
Contract Testing & Senior-Level Tasks Senior-Level API Tasks
API Performance & Load Testing Performance & Load Testing
Jenkins Pipeline Concepts Complete Jenkins Guide

Stage 5 Milestone

Configure your API Automation Framework to:

  • Execute automatically in Jenkins
  • Generate reports
  • Run after every Git commit

Demo APIs for Practice

Demo API Best Used For
RESTful Booker Authentication, CRUD Operations & API Chaining
ReqRes User APIs, Pagination & Data-Driven Testing
FakeStore Complete E-commerce API Flows
Swagger Petstore Swagger & Contract Validation
GoRest Authentication & Role-Based Access
DummyJSON Query Parameters & Nested JSON 
RESTful Booker
      ↓
ReqRes
      ↓
FakeStore
      ↓
Swagger Petstore
      ↓
GoRest

Postman vs REST Assured

Feature Postman REST Assured
Primary Use Manual & Exploratory API Testing Automated API Testing
Java Required No Yes
CI/CD Newman Maven & Jenkins

Which Should You Learn First?

Begin with Postman to understand APIs and validate requests manually.

Then transition to REST Assured to automate those same workflows using Java.

Roadmap Snapshot

Stage Duration Portfolio Outcome
Stage 1 Weeks 1–2 Strong HTTP & REST Fundamentals
Stage 2 Weeks 3–4 Complete Postman Workflow
Stage 3 Weeks 5–7 REST Assured Automation Suite
Stage 4 Weeks 8–9 API Automation Framework on GitHub
Stage 5 Week 10 Jenkins CI/CD Pipeline

Next Steps

Continue learning with:

  • Complete API Testing Guide
  • Complete REST Assured Guide
  • Top API Testing Interview Questions
  • Top REST Assured Interview Questions