SDET - API/Middleware (India)

Welocalize, Inc.; India; Remote; INR 1,201,000 - 1,602,000; Part time

Benefits offered by this job

Limitless Flexibility

Limitless Growth

Limitless Support

Job summary

Welo Global is seeking a Software Development Engineer in Test (SDET) focused on API and middleware testing. You will observe and reconstruct network interactions from onboarding UI, producing sanitized evidence and tracer replay scripts for backend validation.

The role emphasizes API/network analysis over UI automation, with responsibilities spanning HAR analysis, protocol behavior, and edge-case testing. Remote India engagement, 5 weeks, 35 hrs/week.

Qualifications

• 3–5+ years with gRPC-Web, Proto3, HTTP/2, and JSON-RPC/REST protocols.
• Proficiency with proxy/traffic inspection tools including Mitmproxy and Charles Proxy.
• Solid scripting/programming in Python, plus practical use of Postman and cURL for API automation.
• Experience designing and maintaining automated test suites for middleware or API-layer services.
• Understanding of API request structure, headers, tokens, and internal/system parameters.

Responsibilities

• Design, build, and maintain automated API test suites covering gRPC-Web, Proto3, HTTP/2, and JSON-RPC/REST services.
• Export clean, sanitized HAR/network evidence while maintaining traceability between UI actions and network requests.
• Map relevant schemas, headers, identifiers, routing information, and client-injected parameters.
• Use proxy tools to inspect, intercept, and validate network traffic between client and server.
• Develop and maintain API automation scripts using Python, Postman, and cURL for tests.
• Analyze protocol-level request/response behavior to identify defects in serialization, encoding, and transport.
• Collaborate with backend/middleware engineers to define testable contracts and edge cases.
• Improve test automation frameworks for reliability, speed, and maintainability.
• Document findings, automation coverage, and protocol-level limitations.

Skills

gRPC-Web

Proto3

HTTP/2

JSON-RPC/REST

API scripting

Tools

Mitmproxy

Charles Proxy

Browser DevTools

Python scripting

Postman

cURL

Job 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, 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 (with the possibility of full time employment based on performance and project needs in all opportunity)

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.

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.

We may use artificial intelligence (AI) tools to support parts of the hiring process, such as reviewing applications, analyzing resumes, or assessing responses and identifying potential inconsistencies or verification signals in application materials based on available information. These tools assist our recruitment team but do not replace human judgment. Final hiring decisions are ultimately made by humans. If you would like more information about how your data is processed, please contact us.