Customer Success Engineer

Plain is redefining customer support for the next generation of B2B companies. We're building the fastest, most powerful platform to help companies move beyond reactive support and build real customer relationships.

Some of the world's most forward-thinking companies — including Cursor, Ashby, Vercel, and Granola — use Plain to unify customer interactions, collaborate faster, and supercharge their workflows with AI.

We're a small, tight-knit team with offices in San Francisco and London, and teammates across Europe. This role is based in our San Francisco office, with an expectation of 3+ days a week in person.

The role

As our first Customer Success Engineer, you'll own the technical layer of how customers experience Plain post-sale across the board. That means two things in practice: building the resources that help customers go deep without needing a dedicated CSM, and being the person our CSMs pull in when a customer conversation hits a technical ceiling.

Right now, a lot of what makes customers successful lives in people's heads - in onboarding calls, in Slack threads, and one-off explanations. Your job is to take that knowledge and make it available to every customer, before they have to ask.

You'll be in Plain every single day as you're helping customers, which is a uniquely exciting opportunity to be the end user of the tool. You'll feel every rough edge firsthand, be the first to test new features, and the feedback you generate will immediately feed into the product roadmap.

This role also has real room to grow. Depending on what you're drawn to, it can evolve toward deeper technical ownership (more engineering collaboration and complex implementation work) or towards more account management and customer relationships. We're a small team and we build roles around people who perform.

What you'll do

• Build the technical foundation customers need to self-serve — You'll own Plain's documentation, vibe code light PRs, build integration guides, API walkthroughs, and example GitHub repos. When a customer is mid-trial and stuck on their webhook setup at 9pm, your work should be the thing that unblocks them.

• Enable customers to solve problems before they need to ask — You'll pay close attention to what comes up repeatedly in support and onboarding and be responsible for closing those gaps with whatever works: a doc, a short video walkthrough, a better in-app tooltip, a code example. The medium matters less than the judgment about what's actually causing friction.

• Be the technical layer in customer conversations — You'll join onboarding calls when customers have complex integration questions, be the person CSMs pull in when a prospect wants to go deep on the API, and help unblock customers who are stuck mid-setup. You're not owning accounts, but you are owning the quality of the technical experience across all of them.

• Equip the CSM team to have better technical conversations — You'll build the playbooks, guides, and reference materials that let CSMs handle more technical ground on their own. When a customer asks about webhooks or custom integrations, the CSM shouldn't need to immediately escalate; they should have something to reach for.

• Dogfood Plain relentlessly — You'll use Plain every day to manage customer interactions, which means you'll feel every rough edge firsthand. You'll bring that back to product and engineering as specific, actionable signal on what would make customers measurably faster to set up and go live.

This is a great fit if you…

• Have worked in a technical post-sales role at a B2B SaaS company with a developer-facing product.

• Are technical enough to read API docs fluently, write basic TypeScript or GraphQL, maintain a GitHub repo, and ship light PRs. You are comfortable using AI coding tools to move fast and solve problems independently.

• Write clearly and without jargon - you can explain the same concept to a developer and a non-technical buyer and have both land.

• Are a systems thinker - when you see the same problem twice, you fix the underlying cause, not just the instance in front of you.

• Are proactive about finding gaps - you notice a question coming in repeatedly and write the doc before anyone asks.

• Are comfortable spending significant time on written output - docs, guides, working examples, not just in customer conversations.

• Are excited to use a customer support product every single day and have strong opinions about how to make it better.

• See a role without a fully defined ceiling as an opportunity - you're interested in growing toward whatever you turn out to be best at, whether that's deeper technical work or owning customer relationships.

This won't be the right role if you…

• Are looking for a pure engineering role - you'll be in customer conversations regularly and producing a lot of written content.

• Prefer a clearly defined book of accounts with structured check-ins and renewal targets.

• Need well-defined processes and clear briefs before you can produce work.

• Want a management position right now — this is an individual contributor role.

• Aren't excited by the idea of working in person — we work together in our SF office at least 3 days a week.