About Cinder

Cinder is the mission-critical infrastructure that keeps the world's most important digital platforms true to what they stand for. The internet has always been abused by bad actors, and AI is making it exponentially worse, driving fraud, abuse, and manipulation at a scale and speed no human team can fight alone. Cinder gives platforms one command center to fight back: to write and enforce policy, deploy AI agents against abuse in real time, investigate threats, file NCMEC reports, and prove their safety programs are working.

Our customers are some of the largest internet platforms in the world. The decisions made in our software directly determine what stays up, what comes down, and how users are treated.

We're a small, fast-moving team backed by Accel and Y Combinator. We care about being intentional, direct, and deeply focused on solving real customer problems.

Why this role

Once a deal closes, you're the technical owner on the ground. You're the escalation point for the customer, working closely with their CSM and Agent Product Manager (agent PM), and the first line of engineering defense when something isn't working the way they expect.

For some customers, "close" means embedded. You're effectively part of their engineering team, in their Slack, on their calls, building alongside them. The platforms you'd be embedded with have hundreds of millions of users between them. When you fix something, it's not hypothetical. It's live, that day.

What you'd actually work on

• Shape and prove the solution. Work directly with customers to understand their problems, identify the right use cases, and build proofs of concept that demonstrate value and de-risk the path to production.

• Own deployments end to end. Take the technical work from scoping and system design through implementation, rollout, and adoption — partnering with the CSM while owning the engineering plan.

• Build the last mile. Connect Cinder to each customer’s stack through APIs, webhooks, data pipelines, custom workflows, and production-quality code where configuration isn’t enough.

• Enable customer teams. Run technical workshops, document what you build, and give customers the knowledge and tools to operate successfully without us in the room.

• Turn fieldwork into product leverage. Solve issues in the systems you ship, identify patterns across customers, and turn those lessons into reusable tools and improvements to the core product. Own on-call for customers when system downtime means moderation stops.

What we're looking for

• 4-8 years as a software engineer, solutions engineer, or in a similar role in a fast-paced, high-growth environment.

• Solid Python fundamentals. You can read, debug, and extend backend code without hand-holding. Comfortability with SQL, Typescript, React, and GraphQL.

• Real experience owning implementation, not just scoping it. You've configured or customized a product for a specific customer and shipped something that changed what that customer could actually do.

• You are exceptionally comfortable with ambiguity and repeatedly take initiative — you thrive when dropped into unfamiliar situations, learning quickly, and finding ways to deliver value.

• No degree requirement. We care about what you can build, not where you learned to build it. Bootcamp grads are welcome.

Nice to have

• Understanding of trust & safety or safety operations, either firsthand (you've worked in it) or through a specialized background — a T&S-focused master's, for example — that gives you real fluency, not just familiarity.

• Consulting experience where you turned a client's ambiguous ask into a working solution.

• Familiarity with React Query or Strawberry specifically.

• Experience being embedded with a customer or client team, rather than working at arm's length through tickets.

Location & Benefits

Our team is based in London and we believe that in-person collaboration is important. We offer medical and dental insurance benefits through Allianz Global. We hold at least two all-company events per year. We offer paid lunch when our team is in-person.