Senior Dev for Ticketing Web POS

We’re building a new multi-tenant SaaS platform for a large, established business in the event ticketing industry, and we need a senior, hands-on Lead Backend Engineer to help build it from the ground up. The project The platform lets professional ticket sellers manage inventory across multiple online marketplaces from one central system. When a ticket sells on one marketplace, the platform must update or remove that inventory on every other connected marketplace within seconds. That prevents duplicate sales and keeps stock accurate. You’ll work directly with the business owner and other developers to design the architecture, set technical standards and deliver reliable systems for high-volume, time-sensitive transactions. Ticketing experience is not required. Strong backend engineers from SaaS, e-commerce or similar fields are welcome. What you’ll do Lead the design and build of the core backend architecture, including a secure multi-tenant platform with strict data isolation between customers Design and maintain relational databases for inventory, orders, listings, transactions and audit logs Build the core sync engine, using idempotent operations, ordered processing, retries, rate-limit handling and reconciliation Track ticket-level inventory, including reservations, pending orders, partial sales and conflicting transactions Design a standard architecture for connecting multiple marketplace APIs (REST, webhooks, OAuth, API keys) Build background jobs, queues, schedulers and event-driven workflows that cope with API failures, delayed responses and duplicate events Implement secure authentication, encrypted credential storage, monitoring, logging, alerts and audit trails Write automated unit and integration tests, and build test environments that simulate marketplace failures and rate limits Set coding standards, review other developers’ work and document architectural decisions Must have 6+ years of professional backend development experience Strong TypeScript/Node.js, or another established backend language (Python, Go, PHP/Laravel) Strong relational database skills, ideally PostgreSQL (transactions, indexing, migrations, performance tuning) Hands-on experience integrating third-party REST APIs, webhooks, OAuth and API keys Experience with queues, schedulers, background workers or workflow orchestration A solid grasp of concurrency, race conditions, idempotency, retries and distributed system reliability Strong automated testing practices, including mocking external services Experience taking technical ownership and making architectural decisions Excellent written and spoken English Availability to work 8:00 AM – 6:00 PM UK time