Senior Backend Engineer

As a Senior Backend Engineer at FlintVellum, you own the bidding and settlement services that connect a collector's final bid to a completed crypto settlement. You build the auction and payment logic, solve the cases that operations cannot afford to get wrong, and use AI tools as part of your daily engineering work.

What you'll do

• Own bid validation, reserve handling, auction closing and settlement services from design through production
• Build clear records for cryptocurrency payment events, confirmations, failed transfers and payout reconciliation
• Handle simultaneous bids, safe retries and duplicate events without losing or repeating a transaction
• Use AI coding assistants, research tools and review tools to investigate problems, build features and develop tests, checking their output before it reaches production
• Work directly with operations to turn difficult settlement cases into reliable, maintainable services

What you bring

• A working understanding of cryptocurrency, with practical experience buying, holding or transferring crypto strongly preferred
• Understanding of wallets, addresses, networks, transaction fees, confirmations and the differences between Bitcoin, Ethereum and stablecoins
• Ability to build, debug and maintain production backend services in Node.js and TypeScript, with sound SQL, transaction handling and accurate money calculations
• Experience using AI tools for coding, research, debugging and review, with the ability to verify or reject their output
• Clear communication of your decisions and responsibility for the behaviour of the services you ship

What we offer

• Annual base salary of £90,000-£170,000 plus share options
• Full-time, remote role with required overlap on UK working hours
• UK or EU candidates preferred; international candidates welcome

About FlintVellum

FlintVellum is an online auction house for authenticated collectibles including watches, graded trading cards, and sports and film memorabilia. The platform accepts settlement in Bitcoin, Ethereum, USDC and USDT, with seller payouts in GBP or USDC.