Senior Full-Stack Engineer

Senior Full-Stack Engineer Job Description |Engineering | Production Systems Department Engineering Level Senior Focus Area Production Systems Employment Type Full-Time About Sendblue Sendblue is doing something Apple does not offer: we let developers send and receive iMessages programmatically. That is not a feature of a bigger platform. It is the product. Businesses and developers use our API to build CRM integrations, automated messaging workflows, and customer communication tools on top of the channel with the highest open and response rates in mobile messaging. Behind that API is a high-load system: millions of asynchronous messages a day flowing through Node.js services, Postgres, Redis and AWS. We're looking for an engineer who wants to own a significant part of that system — not just ship features on top of it, but design it, keep it reliable, and be accountable for it in production. The Role Most engineering roles at companies this size are narrow. You own a service, a feature area, or a part of the stack. This one is not. The work spans the full system and the accountability is real. If you are the kind of engineer who wants a well-defined lane, this is not the right fit. If you would rather own something real than have perfect clarity about the edges of your job, keep reading. What ownership means here. You will be responsible for a significant part of the company's technical assets: services, data, and the infrastructure that runs them. Not a narrow slice. Real accountability for real systems. What You'll Do Build and support production systems end-to-end: DB schema architecture, system design, security, and the infrastructure underneath.Ship full-stack changes — React frontend, Node.js backend, Postgres schema, and whatever infrastructure change the feature needs — with a clear understanding of how the pieces fit together.Design for scale: message queues, async pipelines, connection pooling, caching, and the failure modes that come with them.Diagnose and fix performance problems in a live system (slow queries, hot Redis keys, worker pool exhaustion, load spikes).Own a significant part of the company's technical assets: services, data, and the infrastructure that runs them.Take part in the on-call rotation, including occasional Saturday shifts (compensated with an extra day off). What We're Looking For Required: 8+ years building and operating full-stack applications in production.Strong system design skills; you've architected systems on your own and lived with the consequences.Hands-on experience with Postgres schema design and performance (indexes, migrations, query plans).Solid understanding of scalability, performance optimization, and asynchronous software — a messenger, a queue-based pipeline, or similar.Security-minded: you think about auth, secrets, data isolation, and blast radius by default.Comfortable being paged, debugging under pressure, and writing the fix so it doesn't happen again.Clear, concise communication and a bias for shipping. Nice to Have: Experience at, or building products similar to, HubSpot, Close CRM, GoHighLevel, Twilio, or MessageBird — CRM, messaging, or communications infrastructure.TypeScript, Next.js, Terraform, Firestore.Startup experience in a high-growth environment. Stack You'll Work With AWS (ECS, RDS, ElastiCache, ALB/NLB, IAM), Postgres, Redis/Valkey, Node.js frameworks (Express or similar), React, Terraform. Category Tools & Technologies Cloud Infrastructure AWS (ECS, RDS, ElastiCache, ALB/NLB, IAM) Database Postgres Caching & Messaging Redis / Valkey Backend Node.js (Express or similar) Frontend React Infrastructure as Code Terraform What to Expect We would rather tell you exactly what this role is like than have you find out after you start. Here is what day-to-day actually looks like: A high-load production system processing millions of asynchronous messages.Real ownership: you'll be responsible for a significant part of the company's technical assets, not a narrow slice.Saturday on-call shifts from time to time, each compensated with an extra day off.A small, focused engineering team where your decisions have direct and visible impact on the product and the infrastructure. About the Interview We evaluate engineers on the experience they have actually had, not on whiteboard exercises. Here is what we want to hear about: Tell us how you'd approach keeping a system like ours reliable under load, and where you've done that before. We want to hear about schema decisions you've made, outages you've handled, and systems you've designed and then had to support. Equal Opportunity. Sendblue is an equal opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees.