Senior Customer Support Engineer

About Prelude Prelude is redefining how companies authenticate and onboard users - turning what's traditionally a cost center into a growth lever. Our flagship product lets businesses send OTP codes with the best price-to-conversion ratio on the market, dynamically selecting the most effective channel in real time (optimized SMS, WhatsApp, and more) while actively blocking spam and fraud that legacy providers miss. Founded in 2022 by former Zenly team members who lived the pain of broken SMS authentication firsthand, we're already serving fast-growing companies across Europe and are expanding into the US. But authentication is only the starting point - we're building the platform for trust at scale, with an ambitious roadmap of market-defining products ahead. Why join us Today, we're a team of 60 and growing, based in Paris, building products that power secure and high-performance user onboarding for companies across the world. We believe small, highly skilled teams outperform large, fragmented organizations, and we are intentional about staying focused on impact, quality, and speed. We operate with a flat org structure and value in-person collaboration, which helps ideas move faster, decisions stay grounded, and teams take full ownership of what they build. Our values - Care We care deeply about our customers, our teammates, and the quality and reliability of what we ship. - Bias for Action We move fast, test in the real world, and iterate quickly rather than over-optimizing in theory. - Ownership We take responsibility end to end, from identifying problems to delivering outcomes and learning from results. ABOUT THE ROLE This is more than a typical support role. You’ll be one of the first senior support hires at Prelude, with real ownership over how the function takes shape as we grow. When a developer at Voodoo is debugging a webhook signature, when X sees unexpected 429s in production, when Tipalti walks through a retry policy with us, or when Suno is troubleshooting a delivery rate dip in our API logs, you’re the person on the other end. You set the tone for how Prelude shows up: technically sharp, calm under pressure, and genuinely useful when something is on fire. You won’t inherit a finished playbook. You’ll help shape it, alongside a team that’s excited to learn from you as much as it wants to support your growth here. WHAT YOU’LL DO - Own end-to-end technical support for our developer customers: engineers integrating our SDKs, debugging webhooks, exploring our API logs, asking thoughtful questions about rate limits and retry behavior. You’ll triage, investigate, and resolve issues, working closely with Engineering whenever a fix or deeper dive is needed. - Help onboard our new customers, partnering with Sales and Engineering to turn a signed deal into a smooth integration and a confident first weeks in production. - Proactively monitor key accounts to look for ways to improve their experience and optimize their usage of Prelude. Spot usage anomalies, untapped features, and integration patterns worth refining, and reach out before customers have to ask. - Develop a deep understanding of how our clients’ businesses work and how their end-users interact with our platform. The more context you carry, the sharper the help you offer, and the more useful the signal you can route back to Product. - Get into our customers’ code. Reproduce their integrations, run their curl calls, read our SDK source when their stack trace points there, and send back answers that include the exact request, the response, and a clear explanation of what happened, not just “we’re looking into it.” - Help us build the foundations of our support function as we scale: runbooks, on-call rotation, escalation paths, SLAs, internal triage, customer-facing status communication. A lot of this is still being defined, and your judgment on what it should look like is welcome from day one. - Bring AI into the workflow from week one. We’d love to hear about spe