Software Engineer, Pub/Sub - Ably

Our everyday digital experiences are in the midst of a realtime revolution. Whether chatting alongside a livestreaming event, receiving realtime financial information, or working with colleagues in an online collaborative environment - consumers simply expect realtime digital experiences as standard. At Ably we’re not just witnessing this revolution, we’re powering it - at scale.

At the heart of our mission lies a commitment to putting developers first. Ably provides a suite of products to build, extend, and deliver powerful digital experiences in realtime, delivering billions of messages for millions of devices every day and supporting organizations like Harness, EA, Panasonic and HubSpot.

Working at Ably means helping to build the infrastructure and technology that will power and shape the future of the internet. The opportunity in front of us is immense. And we’d like your help.

About this role

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. Work across Ably's realtime products including low-level Pub/Sub APIs, our LiveObjects state synchronisation layer, and AI Transport, focusing on new features, performance improvements, bug fixes, and maintenance.
• Work fluently with AI tooling. Use AI tools for planning, spike work, code generation, and documentation, while taking full ownership of correctness, architectural quality, and what actually ships.
• Solve hard distributed systems problems. Collaborate with a talented engineering team to work through genuinely interesting and challenging technical problems.
• Stay driven by 'Developer First' principles. 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. Move with urgency to ship impactful solutions for 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, using it to go faster while applying rigorous human standards.
• A transparent, collaborative 'build in the open' mindset.
• 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 with a successful, deeply motivated, and collaborative team that thrives on innovation, experimentation, and autonomy. We provide a range of perks and benefits to aid development and wellbeing:

• Remote-first and flexible work environment (UK-based teams meet in person once per month in our London hub).
• Equity through our EMI share options programme.
• 28 days of paid annual leave (27 regular days, plus a birthday day off).
• Enhanced parental leave package.
• Home workstation budget of £500 on joining (£150 p/a thereafter).
• Personal learning and development budget of £1000 annually and 5% L&D time.
• Private healthcare with BUPA and medical cash plan.
• Mental wellbeing coaching and counselling from Self Space, plus monthly wellbeing budget via Juno.
• Life assurance, income protection, Tech & Cycle to Work schemes, and fully-paid one-month sabbatical after five years.