Back End Engineer - Senior

WelcomeTrack; Paris; Hybrid; EUR 70,000 - 100,000; Full time

Benefits offered by this job

A 4-day work week

Hybrid working

25 days paid leave

Alan health insurance and Teale (mood/

Job summary

WelcomeTrack is seeking a senior backend engineer to design, build, and maintain scalable services and APIs. You’ll collaborate with a PM and Designer to clarify user needs and priorities, contributing to architecture decisions and the CI/CD pipeline.

The role emphasizes testing, security, and performance, with a collaborative, cross-continental team across Paris and London. You’ll work in a hybrid setup with a 4-day work week and generous leave.

Qualifications

• 7+ years of professional back-end development experience.
• Experience with server-side languages: Elixir, Node.js, Ruby, Python or similar.
• Strong SQL and NoSQL databases, REST APIs, and distributed services.

Responsibilities

• Design, build and maintain scalable back-end services, APIs and database schemas.
• Write clean, well-tested code, and review teammates' code with feedback.
• Take part in architecture decisions and document what you decide.
• Work with PM and Designer to clarify priorities and user needs, not just tickets.
• Debug production issues and fix the root cause.
• Write unit and integration tests, pair when helpful, maintain test coverage.
• Monitor performance and act on degradations.
• Follow security best practices and handle vulnerabilities.
• Handle support requests and bug fixes within SLAs.
• Contribute to CI/CD pipeline and overall developer experience.

Skills

Elixir

Node.js

Ruby

Python

SQL

NoSQL

REST APIs

CI/CD

Testing

Distributed services

Product thinking

French & English

Tools

PostgreSQL

Job description

Most back-end job ads could be swapped between companies without anyone noticing. So here's what's actually specific about this one.

We're Welcome to the Jungle. We build the Hiring Suite companies use to recruit: employer branding, job matching, sourcing and an ATS. Around 260 people between Paris and London, a product used by thousands of companies, and an engineering org that ships regularly rather than endless sprints.

You'd join a cross-functional squad alongside a Product Manager, a Designer and an Engineering Manager. Small team, real ownership, and a say in the technical decisions rather than a backlog handed to you.

Our main back-end stack is Elixir. You don't need to know it, several of our engineers learned it here, but you do need to be the kind of person who finds that interesting rather than inconvenient.

• Design, build and maintain scalable back-end services, APIs and database schemas

• Write clean, well-tested code, and review your teammates' code with actual feedback

• Take part in architecture decisions rather than inherit them, and document what you decide

• Work directly with your PM and Designer to clarify priorities and user needs, not just tickets

• Debug production issues and fix the cause, not the symptom

• Write unit and integration tests, pair when it helps, and keep test coverage honest with our QA team

• Monitor performance, spot what's degrading, and do something about it

• Follow security best practices and handle vulnerabilities when they come up

• Handle support requests and bug fixes within agreed SLAs

• Contribute to our CI/CD pipeline and to the overall developer experience

• A 4-day work week with a fifth flexible one

• Hybrid working

• 25 days of paid leave

• Alan health insurance and Teale, our mental health support platform

• Meal vouchers

• Up to 75% reimbursement of your Navigo pass

• Sick child leave

• Employee Resource Groups

• A professional development plan

Around 7 years of professional back-end development experienceComfortable with a server-side language: Elixir, Node.js, Ruby, Python or similar. Elixir experience is a bonus, curiosity about it is the real requirement.Solid with databases, SQL and NoSQL, and with REST APIs and distributed servicesSerious about testing, CI/CD and software craftsmanship, not as buzzwords but as daily habitsProduct thinking: you ask who the user is and why, before asking howA collaborative mindset. You'd rather unblock a teammate than finish your own ticket first.Clear communication in both French and English. Our engineering teams work across Paris and London.