[Hiring] SDET - API/Middleware @Welo Global

Role Description

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
• 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
• 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.

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 analyzing browser-generated network traffic and reconstructing API behavior 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

Requirements

• 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

Benefits

• ✨ 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.

Company Description

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.