SDET - API/Middleware (India)

Job Overview 
Welo Global is hiring an SDET (Software Development Engineer in Test) to bring deep technical rigor to middleware-layer testing. This role requires strong technical expertise across gRPC-Web, Proto3, HTTP/2, JSON-RPC/REST, proxy-based traffic inspection, and API scripting. The primary responsibility is to observe and reconstruct the network interactions generated by the onboarding UI, including request/response structures, schemas, headers, identifiers, Enums, and client-injected parameters. This is primarily an API/network analysis and evidence-generation role rather than a conventional UI automation or regression-testing role. The resource will produce sanitized network evidence and controlled, benign tracer replay scripts for downstream backend validation.

Project Details
Title: SDET - API/Middleware
Rate: $9.50/hr
Start Date: 19th October
Duration: 5 Weeks
Commitment: 35 Hours per Week
Location: India (Remote)
Job Type: Freelance

Responsibilities

- Design, build, and maintain automated API test suites covering gRPC-Web, Proto3, HTTP/2, and JSON-RPC/REST based services

- Export clean, sanitized HAR/network evidence while maintaining traceability between UI actions and corresponding network requests.

- Map relevant schemas, headers, identifiers, routing information, and client-injected parameters.

- Use proxy tools such as Mitmproxy, Charles Proxy, and browser DevTools to inspect, intercept, and validate network traffic between client and server

- Develop and maintain API automation scripts using Python, Postman, and cURL for functional and regression testing

- Analyze protocol-level request/response behavior to identify defects related to serialization, encoding, and transport

- Inspect and validate request payload structure, including system-level headers (e.g., auth tokens, routing identifiers) and internal/hidden parameters, ensuring correct handling under both valid and malformed conditions

- Collaborate with backend and middleware engineers to define testable contracts and edge-case scenarios

- Continuously improve test automation frameworks for reliability, speed, and maintainability

- Document technical findings, automation coverage, and known protocol-level limitations

Required Qualifications

- Strong hands-on expertise of 3-5+ years with gRPC-Web, Proto3, HTTP/2, and JSON-RPC/REST protocols

- Proficiency with proxy/traffic inspection tools including Mitmproxy, Charles Proxy, and browser DevTools

- Solid scripting/programming skills in Python, with practical use of Postman and cURL for API automation

- Experience designing and maintaining automated test suites for middleware or API-layer services

- Working understanding of API request structure, including headers, auth tokens, and internal/system parameters, and how to test for their correct handling

- Understanding of software engineering practices as applied to test automation (version control, CI integration, code review)

- Strong debugging skills at the network/protocol level

- Experience analysing browser-generated network traffic and reconstructing API behaviour is strongly preferred.

- Experience with HAR analysis, API schema reconstruction, or controlled API replay is strongly preferred.

- Ability to work within approved staging/test environments and follow defined data-handling and test-authorization requirements is required.

Why join Welo Data?  
✨ Limitless Flexibility: Work on projects that fit your schedule while collaborating with a global leader in AI data services and localization.  
🌱 Limitless Growth: Apply your skills, access diverse content types, develop through structured learning, and explore career paths that can lead to permanent roles.  
🌍 Limitless Support: Be part of a global community with real-time assistance from our Community Experience team.  
 
How to Apply? 
Apply now by answering a few quick questions to join our database and become part of our growing community.  
 
We can’t wait to meet you!  
 
About Welo Data

Welo Data, part of Welocalize, is a global AI data company with 500,000+ contributors delivering high-quality, ethical data to train the world’s most advanced AI systems. We’re building smarter, more human AI with a diverse community in 100+ countries. 
 
At Welo Data, Limitless AI. Limitless You. isn’t just a slogan—it’s our promise. We build smarter AI through the power of human contribution, offering limitless opportunities for our global community to grow, contribute, and work on their terms.