Senior Site Reliability Enigneer

Synthesia is the world’s leading AI video platform for business, used by over 90% of the Fortune 100. Founded in 2017, the company is headquartered in London, with offices and teams across Europe and the US. As AI continues to shape the way we live and work, Synthesia develops products to enhance visual communication and enterprise skill development, helping people work better and stay at the center of successful organizations. Following our recent Series E funding round, where we raised $200 million, our valuation stands at $4 billion. Our total funding exceeds $530 million from premier investors including Accel, NVentures (Nvidia's VC arm), Kleiner Perkins, GV, and Evantic Capital, alongside the founders and operators of Stripe, Datadog, Miro, and Webflow. Remote (US East Coast preferred, for timezone coverage) About the team Cloud Infrastructure owns the platform every Synthesia product runs on — AWS, Kubernetes, MongoDB, Temporal, our observability stack, and the vendor and cost relationships underneath them. We're a small, high-leverage team scaling toward a domain-ownership model: small groups that both build and operate the systems they're accountable for. The role We're hiring a dedicated SRE to take real ownership of operational excellence across Cloud Infrastructure. Today, too much critical operational knowledge — vendor relationships, cost management, and incident response — lives with one or two people. Your mission is to take genuine ownership of those domains, make them resilient to any single person, and raise the bar on how reliably we run. This is not simply a ticket-queue or keep-the-lights-on role. You'll own domains end to end: understand them deeply, operate them well, and build the automation and tooling that make them boring. We deliberately pair operational and engineering work so the role grows rather than narrows. What you'll own Incident management & operational excellence — take custody of the incident process: on-call quality, response, post-mortems, and driving down incident count, time-to-detect, and time-to-resolve. Automation & reliability engineering — automate low-frequency, high-consequence operations (the certificate-renewal class of problem — rare, easy to forget, outage-causing when missed), not just the high-frequency toil. You decide what to automate based on risk and blast radius, not just time saved. A platform domain — over time, deep ownership of a domain such as Temporal, observability, or Kubernetes operations, partnering with the engineers building in it. Vendor & third-party management — own key external relationships and integrations (e.g. LLM API providers, third-party services), today managed manually and informally. Bring structure, automation, and bus-factor resilience. FinOps — own cloud and platform cost visibility and efficiency, and the mechanics of how usage maps to billing. What success looks like (first 12 months) Critical operational knowledge is documented and shared — no single point of failure for vendor, cost, or incident response. Measurable reliability gains: fewer SEV1–SEV3 incidents per quarter, faster customer-impact resolution, and a much higher share of incidents caught by monitoring before customers feel them. High-risk manual processes are automated and self-documenting. What we're looking for Strong production operations experience on AWS and Kubernetes; comfortable with MongoDB and scripting/automation in Python. An operations-and-reliability mindset — you take pride in systems that run quietly — paired with the instinct to engineer the problem away rather than absorb it manually. Sound judgement on incidents and risk; calm and clear under pressure. Influences through relationships and evidence, not escalation; comfortable owning a domain and partnering across teams. Bonus: vendor/cost management exposure, Temporal, observability tooling. How we think about this role We don't letterbox engineers. You'll have a clear primary mission (operational excellence) but real domain ownership and the mandate to build — not a fixed lane. We expect the shape of the role to evolve as the team grows.