Senior Backend Engineer (Platform and API)

We’re looking for a senior backend engineer to join the Channels and Platform team at Buffer. You will play a key role in building our public API and creating a future plug-in ecosystem that would elevate Buffer into a platform other developers can build on top of, providing creators the next generation of tools for writing, editing, and managing content.

We’re looking for someone with first-hand experience designing, implementing, and maintaining public APIs and/or extensibility platforms, who enjoys going deep — designing data models, shaping APIs, improving performance, and helping our systems scale with clarity and confidence. You’ll work closely with product, design, and mobile + web engineers to bring ideas to life and keep the user experience smooth and resilient.

We work iteratively and in tight feedback loops, balancing thoughtful engineering with steady momentum. In addition to building a new platform, you’ll help us strengthen our internal systems, making them faster, more scalable, and better equipped to power content creation at scale. There’s real room here to shape this direction and make an impact.

What you’ll do

• Be part of a small, dedicated squad within the Channels and Platform team responsible for Public API development.
• Lead the development of the backend systems for the Buffer Platform. This includes creating an API for core Buffer features, internal services to ensure Public API stability, availability, high performance, and developer tools for platform clients.
• Improve and evolve our internal systems — helping consolidate services into a monorepo, improve tooling and observability, and reduce complexity across the board.
• Collaborate closely with engineers, product, and design to scope work, explore trade-offs, and find the simplest path to something great.
• Make steady improvements to performance, reliability, and data modeling, helping us scale quality over time.
• Participate in on-call rotation (all engineers take on a 24/7 week-long shift once a quarter on average) and day-to-day maintenance work required to keep the lights on the systems owned by the team (this includes bug fixing, addressing security vulnerabilities, incident follow-ups, etc.)
• Contribute to shaping our engineering culture by sharing knowledge, reviewing code, and leading by example.

Helpful skills and experience

• You have practical experience designing, implementing, and maintaining public APIs, plug-in ecosystems, or extensibility platforms.
• You have deep experience with modern stack — we use Node.js, TypeScript, GraphQL, and MongoDB.
• You’ve led backend projects from start to finish — shaping architecture, guiding trade-offs, and delivering reliable systems that support real-world product needs.
• You have strong systems thinking. You look beyond the immediate task, anticipate downstream effects, and help teams converge on architecture that supports the long game.
• You’ve worked across teams to drive platform or infrastructure improvements — whether simplifying service boundaries, improving observability, or evolving internal tooling.
• You’ve contributed to collaborative or multi-user product features, and you understand the data, consistency, and UX considerations that come with them.
• You’re fluent with modern AI tools — not just using them for code generation, but integrating them into how you debug, document, explore ideas, and reduce manual effort.
• You care about performance, scale, and clean abstractions — and know how to measure, prioritize, and improve them pragmatically.
• You’ve influenced engineering culture through code reviews, mentoring, or leading by example, and you’re comfortable being a resource for others on architectural decisions.
• You have a personal stake in the world of content creation; maybe you’ve run a newsletter, built an audience on social media, or regularly shared your own work online. You’ve used Buffer before and care about the experience of planning, creating, and publishing content.
• You thrive in remote, async environments. You’re clear in your thinking, generous with context, and don’t wait for perfect information to get started.
• You’ve likely been doing this for 7+ years, but experience depth and impact matter more to us than a specific number.

Our tech stack

• We use NodeJS, TypeScript, and MongoDB, but part of our core legacy systems are written in PHP (including old APIs)
• We are in the process of migrating to GraphQL, and we use Apollo Client in our web application.
• We are running our services on AWS with Kubernetes. We follow a microservices architecture and are currently moving our services into a central shared monorepo.
• On the frontend, we use React and TypeScript for our web frontends
• We have an internal design system called Popcorn that we started developing last year. It is built with Radix primitives, CSS modules, Storybook, and our own system of design tokens
• We write automated tests with jest, react testing library (for integration tests), and Playwright (for e2e tests)