Senior SDET – Trading Systems | C#/.NET | Python | Backend/API Testing

Introduction

QuellSoft is seeking an experienced Senior Software Development Engineer in Test (SDET) to support a large-scale Equity Derivatives Trading Platform within a leading investment banking environment.

This is not a generic UI automation role. The ideal candidate will have strong hands-on experience across backend, API, database, integration, and UI automation, with the ability to validate complex trading workflows end-to-end.

The candidate should have strong experience with C#/.NET, Python, SQL Server, REST APIs and backend/service testing, along with hands-on experience with TestComplete or a comparable automation framework.

Strong Capital Markets / Trading domain knowledge, particularly Equity Derivatives, Options, Futures, Swaps and trade lifecycle, is highly important for this position.

Key Responsibilities

• Design, develop and maintain scalable SDET automation frameworks.
• Develop automated tests for backend services, APIs, databases, integrations and UI workflows.
• Validate end-to-end trading workflows across multiple application and service layers.
• Perform backend and database validation using SQL Server.
• Develop API and service-level automation using REST and related technologies.
• Automate Windows-based applications and services using TestComplete or equivalent tools.
• Analyze application behavior and, where required, application code to identify effective automation entry points.
• Validate data flow between UI, services, messaging systems and databases.
• Develop automated regression, integration and end-to-end test suites.
• Create test data and utilities required for complex trading scenarios.
• Investigate failures by analyzing application logs, API responses, database records and service behavior.
• Integrate automated tests with Jenkins/Bamboo and CI/CD pipelines.
• Collaborate closely with developers, QA engineers, business analysts and DevOps teams.
• Participate in code reviews and contribute to improving automation quality and coverage.
• Support release validation and continuous testing.

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Required Skills

SDET / Automation

• 5+ years of hands-on SDET / QA Automation experience.
• Strong experience developing automation frameworks rather than only executing existing scripts.
• Strong programming experience in C#/.NET.
• Strong Python scripting/automation experience.
• Experience with TestComplete is strongly preferred.
• Experience with Selenium, Ranorex, UFT or similar automation tools is beneficial.

Backend / API / Database Testing

Strong backend testing experience is required.

• Experience testing backend services and distributed applications.
• Strong experience with REST API testing and automation.
• Experience with Postman, RestSharp, REST Assured, Newman or similar tools.
• Strong SQL Server experience.
• Ability to write SQL queries for:
  • Data validation
  • Transaction validation
  • Test data preparation
  • Reconciliation
  • Backend assertions
• Experience validating data across UI → API/service → database.
• Experience with integration and end-to-end testing.
• Experience troubleshooting failures across application, service and database layers.

Trading / Capital Markets

Capital Markets experience is highly preferred and will be a major factor in candidate selection.

• Experience working with Capital Markets / Investment Banking / Trading Systems.
• Strong understanding of Equity Derivatives.
• Knowledge of one or more of:
  • Options
  • Futures
  • Swaps
  • Bonds
• Understanding of the end-to-end trade lifecycle, including:
  • Order creation
  • Execution
  • Allocation
  • Enrichment
  • Booking
  • Confirmation
  • Settlement
• Experience testing Order Management / Trading platforms.
• FIX Protocol experience is strongly preferred.

CI/CD & Engineering

• Jenkins, Bamboo or equivalent CI/CD tools.
• Git / Bitbucket.
• Experience integrating automated tests into CI/CD pipelines.
• Windows Services and/or IIS applications.
• PowerShell and/or scripting for test/deployment automation.
• Strong debugging and troubleshooting skills.

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Preferred / Nice-to-Have Skills

• C++
• WCF
• MSMQ
• RabbitMQ
• Kafka
• SpecFlow / Cucumber / BDD
• NUnit / xUnit / MSTest
• Docker
• Splunk
• Octopus Deploy
• PowerShell DSC
• JMeter / k6
• SonarQube
• Pact / contract testing
• AI-assisted test automation tools such as GitHub Copilot or Claude Code

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What We're Looking For

The ideal candidate is someone who can move beyond simply automating UI test cases and can understand how a trading application works across its entire technology stack.

You should be comfortable asking questions such as:

Did the trade reach the backend?
Was the API response correct?
Was the transaction persisted correctly in the database?
Did the downstream service receive the message?
Does the UI correctly reflect the backend state?

Experience testing these types of end-to-end trading workflows is highly valuable.

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Education & Other Requirements

• Bachelor's degree in Computer Science, Engineering or related field preferred.
• Excellent communication and analytical skills.
• Strong troubleshooting and problem-solving ability.
• Ability to work independently in a fast-paced environment.
• Experience working in Agile/Scrum teams.