Backend Engineer

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 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.

You'll start by working on the Prelude Dashboard and API, our two main touch-points with customers. The API lets businesses send OTP codes to their users' phone numbers, and the dashboard lets them analyze their traffic and get details on each authentication flow.

You will take part in the continuous effort of making it better, faster and more reliable by working closely with engineers, a product designer and of course, customers.

As a new engineer within the Prelude Team, you have the opportunity to rapidly grow your skillset by working in a position that allows you to perform a wide array of tasks that extend from designing distributed systems, full-stack development and infrastructure management.

• Building and scale a distributed system based on AWS technologies such as DynamoDB, SQS, Redshift and Lambdas and using the Go programming language.

• Build a snappy full-stack app using cutting-edge tech (Next on Vercel, gRPC)

• Work on the next version of the Prelude API, which we strive to be industry-leading in terms of usability, performance and functionality.

• Ensure that our services are scalable, extensible, reliable, and performant.

• Help deploy and scale our fraud prevention model to hundreds of large customers.

• Develop and maintain internal tools to increase our efficiency.

• Interact with customers on a daily basis to assist them and build features around their needs.

• Participate in on-call rotations to guarantee the stability and reliability of our APIs.

• You have a strong technical background, including 4+ years of experience designing and engineering large-scale systems.

• You have strong coding skills in Go, ideally with experience in a high-scale environment

• You prefer simple solutions and designs to complex ones, and have a good intuition of what will last a decade and scale.

• You have a product-led mindset: you code for the output, not for the process.

• You are fluent in english.

• Experience working with Rust, Typescript or any other highly scalable language is a plus

• You have some experience building frontends with modern, component based frameworks such as React, Angular or Vue

• Competitive compensation package with BSPCEs.

• Hybrid working style: 3 days at the office and 2 day at home, with 4 weeks of remote per year.

• We will provide you with the gear you need for your role (a laptop and a phone, for on-call rotations)

• An annual offsite in a great location (last one was at La Pradet!)

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, followed by a system design problem and 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.