SDET - API/Middleware

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.