Senior Software Engineer - Full Stack

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 You'd be building the infrastructure that some of the largest online communities in the world depend on to function. The problems aren't hypothetical: state-sponsored disinformation, CSAM reporting, coordinated abuse at scale. The software you build is used daily by the reviewers, investigators, and T&S leads making the calls that define what a platform stands for. This is an early-stage company with a mature product and real enterprise customers. You'll have outsized influence on archit [... source excerpt omitted ...] hat you'll work on This isn't a generic full-stack role. Here's what's actually on the roadmap right now and what you'd be contributing to: AI agents that review content against customer policies, callable from within our durable workflow engine. We're moving from hardcoded LLM prompts to a configurable agent spec that customers can edit and deploy themselves. A workflow engine built on Restate for durable execution. Engineers build new nodes that customers wire together to automate moderation pipelines, NCMEC reporting, enforcement actions, and more. Review queue tooling: the core UI where moderators and investigators spend their day. You'd work on features like QA decision [... source excerpt omitted ...] ay user communications: building integrations (Salesforce, Zendesk) so moderators can contact users and see conversation history without leaving Cinder. Reliability at scale. Our customers process high volumes of content through review queues, workflows, and AI agents. You'd help define SLIs, improve pipeline throughput, and own oncall for systems where downtime means moderation stops. What we're looking for 5+ years building production software, with experience across the stack: Django or similar backend frameworks, React or similar on the frontend, relational databases, and message/event systems. You've identified a customer problem yourself, not just been handed a ticket,