E-Commerce Backend Developer

Onkatec; İzmit; On-site; TRY 520,000 - 700,000; Full time

Job summary

ToptanTR is seeking an E-Commerce Backend Developer to join their team and build features on a .NET-based platform handling real order and payment traffic.

You will optimize performance, reliability, and scalability while integrating with ERP, e-invoicing, and other third-party services. The role emphasizes code quality, testing, and collaborative development.

Qualifications

• Experience developing production applications with C# and ASP.NET Core.
• Strong knowledge of SQL Server, T-SQL, indexing and execution plan analysis.
• Practical experience with caching, concurrency and data consistency.
• Experience with REST API design and third-party service integrations.

Responsibilities

• Develop features across catalog, search, cart, campaign, coupon, order, payment, shipping, commission and invoicing processes.
• Build and maintain 3D Secure virtual POS, shipping carrier, ERP and e-invoice integrations.
• Analyze and optimize SQL Server queries and stored procedures using execution plans.
• Monitor database performance and carry out necessary query and index optimizations.
• Design and develop Redis caching and cache invalidation strategies.
• Improve search results quality with Meilisearch, Elasticsearch or similar.
• Ensure Hangfire background jobs are reliable and observable.
• Back code with xUnit tests and participate in code reviews.

Skills

C#

ASP.NET Core

REST API design

Unit testing

Git

Performance optimization

Tools

SQL Server

T-SQL

Redis

Meilisearch

Elasticsearch

Docker

Kubernetes

CI/CD

Job description

Employee Type: Full Time – Office
Job Type: E-Commerce Backend Developer
Industry: E-Commerce / B2B Marketplace

E-Commerce Backend Developer | ToptanTR

As part of our consulting engagement with ToptanTR, we are looking for an E-Commerce Backend Developer to join the ToptanTR team.

ToptanTR is a multi-vendor B2B wholesale marketplace where sellers list and manage their products, buyers make wholesale purchases, and order, payment, shipping, commission and invoicing processes are all handled under one roof.

We are looking for a teammate who will build new features on a .NET-based platform that handles real order and payment traffic, and who will continuously improve system performance and reliability by measuring them.

What You’ll Do

• Develop features across catalog, search, cart, campaign, coupon, order, payment, shipping, commission and invoicing processes
• Build and maintain 3D Secure virtual POS, shipping carrier, ERP and e-invoice integrations
• Analyze and optimize SQL Server queries and stored procedures using execution plans
• Monitor database performance and carry out the necessary query and index optimizations
• Design and develop Redis caching and cache invalidation strategies
• Improve the quality, performance and ranking of search results with Meilisearch
• Make Hangfire background jobs reliable and observable
• Back your work with xUnit unit tests
• Take an active part in code reviews
• Analyze production issues using Sentry and Grafana data to identify their root causes

What We’re Looking For

• Experience developing production applications with C# and ASP.NET Core
• Strong knowledge of SQL Server, T-SQL, indexing and execution plan analysis
• Practical experience with caching, concurrency and data consistency
• Experience with REST API design and third-party service integrations
• A habit of writing unit tests
• Experience working in a team with Git-based development and code reviews
• A development approach focused on performance, scalability and reliability

Nice to Have

• Experience with nopCommerce or similar plugin-based e-commerce platforms
• Knowledge of marketplace business rules such as commissions, seller payouts and seller management
• Experience with Docker, Kubernetes (AWS EKS) and CI/CD
• Experience with Meilisearch or Elasticsearch
• Experience with linq2db, Dapper or FluentMigrator
• Experience with load testing and performance profiling