Freelance Backend Engineer (Node.Js/Golang) - Wizz

About Voodoo

Founded in 2013, Voodoo is a tech company that creates mobile games and apps with a mission to entertain the world. Gathering 800 employees, 7 billion downloads, and over 200 million active users, Voodoo is the #3 mobile publisher worldwide in terms of downloads after Google and Meta. Our portfolio includes chart-topping games like Mob Control and Block Jam, alongside popular apps such as BeReal and Wizz.

Team

Our consumer apps teams are at the forefront of crafting innovative and engaging apps for daily enjoyment.

Our ambition extends beyond gaming to entertain a global audience. Millions of people around the world, especially in the US, download and use the apps we create.

You'll be working on Wizz, a social app specifically designed for teens, boasting over 3 million monthly active users in the US and UK. Wizz is a friend-finding and chat app where young people can safely express themselves and connect with like-minded peers in an authentic, pressure-free environment. Unlike other social media platforms that focus on followers, posts, or passive consumption, Wizz offers young people a space to have meaningful 1:1 conversations with peers.

As a member of a high-performing team of 20, you'll collaborate to further scale and enhance Wizz, fostering a spirit of goodwill and creativity. As Wizz continues its dynamic growth and development, we are seeking an ambitious Senior Backend Engineer to join.

Role

We are looking for a Backend Engineer (Freelance) who is technically strong, proactive, product-minded, and able to take ownership of a critical transition. You won’t only write code, you will drive and execute the migration of backend services from Node.js to Golang, influence architectural decisions, and help shape the long-term technical strategy behind Wizz.

Your ability to challenge assumptions, propose solutions, and collaborate with product and engineering teams will be essential.

Your mission:

Lead and own the backend migration from Node.js to Golang, ensuring scalability, performance, and reliability for millions of users

Collaborate closely with product & engineering teams to contribute to technical direction and decisions

Design, rewrite, deploy and maintain highly scalable backend services in Go

Ensure a smooth progressive migration strategy with minimal operational impact

Integrate and manage third-party services (analytics, moderation, cloud tools)

Promote best backend practices in reliability, observability, and infrastructure

Improve performance for high-traffic distributed systems

Contribute to architecture evolution to support fast product iterations and safe user environments

Share knowledge and support the team in adoption of Go

Our stack

Language and libraries: Node.js, Fastify, Socket.io, Go, Firebase

Databases: MongoDB, Redis

Infrastructure: Cloud Run, Pub/Sub, S3, CloudFront, Big Query

Ops: Github Action, AWS CLI, gcloud CLI, Docker, microservice architecture

iOS: XCode, GitHub, Cocoapods (public and private)

Profile

Passion for consumer apps and user-centric products

Fluent in French

5+ years of backend engineering experience

Strong expertise in Node.js and Golang

Previous experience migrating or rewriting services at scale

Proficient with AWS or GCP

Comfortable with high-traffic architectures & distributed systems

API development experience

Familiarity with our tech ecosystem is a plus

Background in social media applications is a plus

DevOps experience (Terraform, CloudFormation…) is a plus

Benefits

Competitive salary upon experience

Wellness activities in our Paris office

Remote days on Mondays, Tuesdays and Fridays

Voodoo just won the award for Best Office Space in France