Backend Engineer - Crypto Fintech

No corporate vibes here. No unnecessary meetings. A lot of coding and a lot of problem solving. Direct ownership of the codebase. Polish-American founders, so fluent English is a must-have. Equity possible after the trial period.

As a Founding Backend Developer, you’ll play a critical role in shaping the architecture and development of our next-generation crypto banking platform.

You’ll work closely with the founding team to build secure, scalable financial infrastructure, integrating blockchain solutions, fiat payment rails, and lending systems.

This is an opportunity to take ownership of a complex backend system from day one, solving high-security and high-performance challenges in the fintech space.

Verdono is a platform offering: a full suite of financial services, including digital asset-backed loans, high-yield saving accounts, and secure payment cards, allowing you to spend, save, and invest—all in one place.

Tech stack:

Primary: NestJS, TypeScript, tRPC/GraphQL, WebSockets, Redis, PostgreSQL, Prisma or Drizzle, Kafka, or RabbitMQ

Nice to have: Bun, gRPC, Blockchain-based DBs (e.g., QLDB)

Big plus: AWS, Containerization (Docker, Kubernetes)

Who you are:

• You have 6+ years of experience in backend development, preferably in fintech or crypto.
• You’re proactive in optimizing system performance and ensuring reliability.
• You have experience designing and building scalable microservices and APIs (RESTful and tRPC/GraphQL).
• You’ve built and optimized CI/CD pipelines to streamline deployments and DevOps infra before.
• You have experience working with high-security environments, handling sensitive data, encryption, and authentication protocols.
• You understand Bitcoin, Ethereum, and other major blockchain technologies.
• You’re familiar with DeFi protocols and Layer 2 solutions (a plus).
• You have experience integrating blockchain infrastructure through third-party providers like Fireblocks (wallets, staking, custody).
• You understand crypto custody and wallet systems, including hot/cold wallet management and transaction signing flows.
• You have strong experience in private key security, cold/hot wallet architecture, and encryption best practices.
• You understand authentication mechanisms such as OAuth, JWT, and 2FA.
• Experience working with KYC/AML/KYT solutions is a plus.
• You have experience working with fiat on/off-ramps (e.g., MoonPay).
• You’ve worked with banking APIs.
• Fluent in written and spoken English.

What you’ll do:

• Architect and develop a highly scalable backend infrastructure
• Design and implement microservices and APIs
• Work with blockchain infrastructure to handle crypto custody, staking, and lending through third-party providers like Fireblocks.
• Develop and optimize our loan engine, collateral management, fee management systems**,** policy engines for transaction rules(i.e. real-time balance tracking and automated wallet operations), and margin call automation to support crypto-backed lending.
• Integrate fiat banking systems, including SEPA, SWIFT, and card payment processing, ensuring compliance with financial regulations.
• Build high-security wallet infrastructure, handling hot/cold storage, transaction signing, and key management.
• Ensure top-tier security, implementing KYC/AML solutions, encryption standards, and authentication mechanisms.
• Implement real-time risk management and monitoring, using automated flagging, suspicious activity reports, and liquidation risk alerts.
• Optimize system performance and reliability, scaling backend services for high availability and low latency.