Software Engineer, Pub/Sub in London

The Pub/Sub team owns the core backend that underpins Ably's entire edge messaging platform. This is a rare opportunity to work on genuinely hard distributed systems problems at planet scale; designing and improving the infrastructure that developers and their users depend on in production every day. You'll be hands-on, driving the development of new functionality and initiatives to scale and improve Ably's core Pub/Sub platform.

We work in an AI-first engineering culture: AI tools are part of how we plan, prototype, and iterate - but engineers own every technical decision, and human judgment is the quality bar that everything is measured against.

Day to day you will:

• Deliver key platform functionality. You'll work across Ably's realtime products including our low-level Pub/Sub APIs, our LiveObjects state synchronisation layer, and AI Transport, the messaging backbone purpose-built for AI agent communication, focusing on shipping new features, performance improvements, bug fixes and maintenance.
• Work fluently with AI tooling. You'll use AI tools for planning, spike work, code generation, and documentation, while taking full ownership of correctness, architectural quality, and what actually ships. Fast iteration is expected; shortcuts in quality are not.
• Solve hard distributed systems problems. You'll collaborate with a talented engineering team to work through genuinely interesting and challenging technical problems.
• Stay driven by 'Developer First' principles. You'll work closely with other engineers to identify and address the most important problems developers face when building on Ably.
• Push to see your work in customers' hands. You'll move with urgency to ship, because you care about the impact your work has on the developers and companies building on our platform.

We'd love to talk if you have:

• A strong interest in, or direct experience with, distributed systems and large-scale infrastructure.
• Experience working with or building messaging queues, pub/sub systems, or streaming systems at scale.
• Extensive experience with a high-level server-side language (Node.js or Go preferred).
• The ability to self-start, work through ambiguity, and make good decisions without a lot of hand-holding.
• A practical relationship with AI tooling. You use it to go faster and think more clearly, and you know where to apply rigour that AI alone can't provide.
• A transparent, collaborative build in the open mindset. You're comfortable sharing your work publicly, whether that's writing about what you're building, talking about technical decisions, or contributing to the broader developer conversation around the problems Ably solves.
• Experience in dynamic, early-stage environments where adaptability and resourcefulness are core skills.

Bonus points if you have:

• Experience building developer-first products.
• Experience with products brought to market through a product-led growth approach.

What’s it like to work at Ably? We’re tackling planet-scale problems and our ambitions are a testament to that. You’ll join a successful, deeply motivated and collaborative team that thrives on innovation, experimentation and autonomy. We believe in fostering a culture that’s built on inclusivity and mutual respect among all team members, and we recognise that each individual is different and will want to be supported in their role in different ways.

We provide a range of perks and benefits to aid folks' development and wellbeing, allowing them to be their best selves and do great work:

• A remote-first and flexible work environment.
• Equity through our EMI share options programme.
• Enhanced holiday allowance of 28 days of paid annual leave.
• Enhanced parental leave package.
• Home workstation budget of £500 on joining and £150 p/a thereafter.
• Personal learning and development budget of £1000 annually, and 5% L&D time during working hours.
• Private healthcare with BUPA.
• Medical cash plan to cover a range of medical and dental costs.
• Mental wellbeing coaching and counselling from Self Space.
• Monthly wellbeing budget via Juno.
• Life assurance and income protection.
• Access to Tech & Cycle to Work schemes.
• A fully-paid one-month sabbatical after five years with Ably.

Diversity, Inclusion & Belonging at Ably: We believe our differences as individuals is what makes us great. Our people are at the heart of what we do, and we encourage everyone to be their most authentic self at Ably: we see inclusivity and openness as fundamental to creating long-term success as an organization. We encourage applications from all backgrounds regardless of age, disability, gender, sexual orientation, parental status, race, religion, educational background or neurodiversity.

If you enjoy working as part of a technology company, value open source, and love solving hard problems - then we’d love to hear from you, regardless of whether you fit the job description exactly or not.