Full Stack Engineer en Prelude

About Prelude

Prelude is on a mission to transform how companies onboard and authenticate users. We help businesses verify their users with greater efficiency, less friction, and stronger security — ultimately increasing conversion rates and reducing costs.
Our flagship product focuses on authentication, enabling companies to send OTP codes with the best price-to-conversion ratio available. We do this by dynamically selecting the most effective delivery channel (e.g. SMS via the optimal carrier vs. WhatsApp), while actively blocking costly spam and fraud attempts that traditional providers often miss.
Founded just two years ago, Prelude has already achieved healthy financials and strong product-market fit. But authentication is only the beginning. With a pipeline of bold, market-defining ideas, we’re building the platform for trust at scale — and we’re excited to shape the future of onboarding and user verification with you.

The Team

The Prelude team started with four former Zenly team members, a social network acquired by Snapchat in 2017. We created Prelude in response to a problem we had there: the current SMS authentication offering is too expensive, of poor quality and offers little to no protection against spam. We believe that having a small team of committed and skilled people with a flat hierarchical organization is the best way to build a tech company. It forces us to focus on what matters and only on what matters: delivering value to our customers. We also believe that at our current stage, we need to be face-to-face in our offices in Opera, so that ideas can flow freely and collaboration is spontaneous.

About the role

Join us as a Full‑stack Engineer to craft fast, reliable user experiences end‑to‑end. You’ll ship polished React front‑ends, design and implement scalable back‑end services, and contribute directly to our web SDKs that power device fingerprinting, session management, and silent verification.

What you’ll do

• Build beautiful, accessible UI from Figma designs to production using HTML, CSS, TypeScript, and React.

• Design and implement back‑end services and APIs in Go, leveraging gRPC where it fits.

• Work with data stores and infrastructure like DynamoDB, Aurora, Redis, AWS Lambda, and SQS to build reliable systems.

• Contribute to and maintain client web SDKs used by customers and internal teams.

• Collaborate closely with product and design, making pragmatic trade‑offs to ship quickly and safely.

• Uphold code quality through testing, reviews, and thoughtful architecture.

What makes you a great fit

• 5+ years building front‑end applications with React, TypeScript, and CSS. Experience in B2B SaaS is a plus.

• 3+ years building back‑end APIs in a major language such as Go or TypeScript/Node.

• Strong product sense: you optimize for outcomes, not ceremony.

• Bias for simplicity and solutions that scale over years, not weeks.

• Fluent in English.

Nice to have

• Experience building and distributing web SDKs.

• Hands‑on Go and/or gRPC experience in production.

• Familiarity with AWS services like Lambda, DynamoDB, Aurora, and SQS.

How we work

• Product‑led and customer‑obsessed. We measure success by shipped impact.

• Pragmatic engineering: small, well‑factored changes that add up quickly.

• Collaborative, kind, and direct feedback culture.

Interview Process

The interview process will start with a 30 min introductory call followed by two technical assessments.

You will then be invited to our offices in Opera, where we will work together on a small practical project for about an hour as well as an informal discussion about your past experiences and your working style.

We don't expect you to ace all these stages, we will evaluate your creativity and how you approach difficult problems. You should consider applying even if you don't meet all the criteria.