
Senior Crypto Developer
- Amsterdam, Noord-Holland
- Vast
- Voltijds
- Own backend micro-services in Node.js/TypeScript that interface with multiple blockchains, following clean-architecture and test-driven development principles.
- Run and optimize bitcoin-core (BTC/LTC) nodes—manage UTXO sets, fee estimation, mempool monitoring, and wallet RPCs for high-volume deposit and withdrawal flows.
- Build and maintain Ethereum transaction pipelines using ethers.js—handle ERC-20/ERC-721 token transfers, reorgs, transaction signing/broadcasting, and nonce management.
- Integrate additional L1/L2 networks by abstracting blockchain-specific logic behind a unified service layer, enabling rapid support for new tokens and chains.
- Leverage Fireblocks or similar MPC/custodial APIs to manage secure wallet operations, policy enforcement, and multi-signature approval flows.
- Develop and maintain frontend Web3 wallet integrations (e.g., MetaMask, WalletConnect, Ledger) using TypeScript/React, delivering seamless UX and real-time transaction feedback.
- Build scalable deposit & withdrawal infrastructure, including queueing systems, idempotent webhooks, reconciliations, wallet sweeps, address management, and fee optimization.
- Embed security and compliance features—KYT screening, whitelisting, secrets management, and rate-limiting—into application code and CI/CD pipelines.
- Monitor blockchain health and system performance—establish SLAs, create alerting systems, implement incident response plans, and lead post-mortems.
- Document APIs, architecture decisions, and operational runbooks; mentor peers through code reviews and knowledge sharing sessions.
- 5+ years of backend development experience, including significant work with Node.js and TypeScript
- Strong understanding of blockchain fundamentals, especially UTXO vs. account-based models
- Hands-on experience with Ethereum, Bitcoin, and L2s (e.g., Arbitrum, Optimism, Polygon)
- Familiarity with Web3 libraries such as ethers.js, web3.js, and experience interacting with RPC APIs
- Deep understanding of secure wallet management practices and MPC technology
- Proficiency in front-end development using React and Web3 provider integrations
- Experience in designing high-availability systems and real-time transaction infrastructure
- Strong emphasis on security, performance, and scalability
- Excellent documentation and communication skills
- A dynamic and supportive work environment
- Opportunities for professional growth and development in a rapidly evolving industry
- Competitive salary and performance-based incentives
- The chance to work with a passionate team in the forefront of blockchain innovation