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.

Work arrangement
Yes