Backend Engineer (.NET / C#)

Cooperation type: Contractor Agreement

About us:

CoinPayments is the first and leading crypto payment processor worldwide. With over 1 million users and more than 120,000 registered merchants in over 190 countries, CoinPayments has become one of the most widely used multi-crypto payment systems available online. Since 2013, we have developed a complete crypto payment gateway that allows merchants to accept over 100 cryptocurrencies and hold over 2,000+ altcoins, all on a single platform.

We are looking for Backend Engineer (.NET / C#) to join our team. You will work across our backend services, rotating where the work is needed. Every engineer owns features end-to-end, reviews peers' code, and operates what they build.

Responsibilities

- Build features end-to-end: data model, API, background processing, tests.

- Write unit and integration tests. Treat CI quality gates as part of done.

- Review code. Hold a high bar on readability, correctness, and test coverage.

- Contribute to service design: data modeling, transaction boundaries, retries, idempotency, observability.

- Own what you ship, not just what you write. Design for observability from the start, confirm your feature works in production, and handle incidents when they happen.

- Collaborate with product, QA, and infrastructure on release planning and rollout.

- Refactor weak spots and retire legacy patterns over time.

Requirements (Must have)

- 4+ years of production experience in C# / .NET building backend services on ASP.NET Core.

- Strong fundamentals:

- Relational databases: schema design, indexing, transactions, query performance.

- HTTP APIs (REST and gRPC), background processing, retries, idempotency.

- Testing: unit and integration, mocking, test design.

- Solid grasp of distributed systems concepts: timeouts, retries, partial failure, message ordering, eventual consistency.

- Working knowledge of an observability stack: structured logs, metrics, traces.

- Proactive use of AI coding assistants (Codex, Claude Code, or similar) as part of daily work. AI is a tool that helps you move faster. You remain the engineer: you read every line, you understand every change, you are accountable for the result. No blind acceptance of generated code.

- Strong engineering hygiene: tests are not optional, code reviews are taken seriously, you read code before you change it.

- English at B1 or higher: comfortable reading and writing technical English, participating in async discussion and meetings.

Bonus Points

- Experience with actor or virtual-actor frameworks.

- Experience with message-driven systems and long-running workflows (sagas, orchestrators).

- Background in fintech, payments, or crypto: custodial wallets, ledgers, on-chain integrations, regulated environments.

- Experience integrating third-party providers (KYC, payments, banking) and handling their webhooks.

- Experience improving legacy code and reducing technical debt without breaking things.

- Cloud familiarity at the level of "I can read the infra and not be lost".

What we value

- Engineering quality over short-term hacks. We pay back our debts.

- Ownership: you ship it, you operate it, you fix it.

- Clear written communication. Most decisions live in PRs, tickets, and chat.

- AI as a force multiplier, used by engineers who still own their code.

- Curiosity and willingness to learn parts of the stack you have not touched.

What we offer:

• Competitive compensation package aligned with your experience and impact
• Fully remote work environment with flexibility and autonomy
• Access to modern AI-powered tools and technologies that help you work smarter and faster
• Opportunity to influence products, processes, and technical decisions — not just execute tasks
• A culture that values initiative, ownership, and problem-solving
• Fast-moving environment with minimal bureaucracy and direct communication

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