Backend Engineer
We are building a high-load payment platform (PSP) processing transactions 24/7/365 across multiple regions and providers.
Our stack:
- .NET 9
- Apache Kafka
- PostgreSQL
- Redis / Valkey
The platform is built around event-driven architecture with real production requirements for:
- delivery guarantees
- idempotency
- resiliency
- observability
- fault tolerance
This is not a CRUD product role.
You will work on infrastructure-critical systems directly impacting transaction reliability and routing efficiency.
What you’ll do
Develop and evolve the core payment platform:
- transaction flows
- routing engine
- webhook infrastructure
- provider integrations
- Design new services and integrations — from architecture and contracts to production rollout
- Participate in architecture discussions and technical decision-making
- Perform code reviews and contribute to engineering standards
- Work closely with the connectors team (Python / TypeScript)
What we expect
Platform & Backend
Strong senior-level experience with:
- C#
- .NET 8/9
- ASP.NET Core
- Deep understanding of:
- async programming
- concurrency patterns
- thread-safety issues
Production experience with:
- Minimal APIs
- Hosted Services
- Dependency Injection
Infrastructure & Data
Hands-on Apache Kafka production experience:
- at-least-once delivery
- consumer groups
- manual offset commits
- idempotent consumers
Strong PostgreSQL knowledge:
- SQL-first mindset
- query optimization
- execution plan understanding
Experience with Redis / Valkey:
- caching strategies
- invalidation patterns
- Sentinel or Cluster setups
Architecture
- Experience building microservices with event-driven communication
- Strong understanding of:
- inbox/outbox patterns
- delivery guarantees
- idempotency
Docker production experience
Understanding of container orchestration:
- Docker Swarm
- Kubernetes is also relevant
Payments / Fintech Domain
- Experience in fintech or payment systems
- Understanding of:
- PayIn / PayOut flows
- webhooks
- callbacks
- retry cascades
Production experience with webhook security:
- HMAC signatures
- replay protection
- timestamp validation
Practical understanding of PCI DSS scope:
- sensitive data handling
- logging restrictions
- secure storage practices
Quality & Observability
- Ability to properly test critical business logic
Understanding of: - unit tests
- integration tests
Experience with observability tooling:
- structured logging
- metrics
- distributed tracing
AI-Assisted Engineering
AI-assisted development is a standard part of our engineering culture.
We expect engineers to confidently use tools like:
- Claude Code
- Cursor
- GitHub Copilot
- or equivalent AI assistants
Important:
- You fully understand every line of code you commit
- You do not blindly trust generated code
- You know how to properly structure prompts, context, and acceptance criteria
- You understand where AI accelerates delivery — and where manual engineering judgment is required
Nice to have
- Lua / LuaJIT experience
- OpenAPI-first development
- openapi-generator experience
- Python or TypeScript background
- Hot-reload configuration systems via event buses
- Real production experience with Git submodules
Why join us
* High-load real-world fintech infrastructure
* Complex engineering challenges instead of routine CRUD
* Direct impact on platform scalability and transaction reliability
* Strong engineering culture with modern tooling and AI-first workflows
* Opportunity to influence architecture and technical direction
* International product environment