Vacancy

Senior Developer

32–40 hours Mijdrecht (hybrid) Permanent contract

At Day Six we build software that makes our clients' work easier: client portals, ordering environments, web applications and integrations between systems. It almost never starts with a technical wish, but with a process that is stalling somewhere. We are looking for the developer who quickly gets to the bottom of that process and independently turns it into a working solution. Not a ticket processor, but someone who carries a project from a to z and puts their name on it.

What you will do

You join the first client meeting and ask the questions that expose the real problem
You translate that into a plan, a data model and a build approach: what we build, and what we deliberately don't
You build with a broad, modern stack: PHP and Laravel, modern JavaScript and TypeScript, Tailwind and Node where needed
Integrations with accounting, logistics and communication systems are your daily bread
You work AI-first with tools like Claude Code and Codex, with GitHub at the base. You review everything that comes out, because you are responsible for what goes live
You deliver, explain to the client in plain language what you built, and make sure it keeps running afterwards
You review your colleagues' work and help our junior grow

What you bring

At least five years of experience as a developer. You can write code entirely yourself when needed, and you spot weak code when AI writes it for you
You quickly get to the bottom of a business process and see the problem behind the question
Security is second nature: permissions, input, secrets, privacy. You don't push anything live you don't stand behind
You explain tech in plain language, to the client and to a colleague without a technical background
Experience with API integrations, authentication and roles, and with applications that handle money or personal data
Bonus points: PWAs and service workers, Node or TypeScript, cloud storage and serverless, and GDPR in practice

What we offer

A good salary in line with the market, matching your experience
32 to 40 hours a week, hybrid from Mijdrecht
Paid AI tooling (Claude Code, Codex) and the hardware you need
A training budget and the time to actually use it
A small team with short lines: you talk directly to the client and to the owners
Lots of different projects. You won't spend years on one product

How applying works

Send your CV and a link to something you built: GitHub, a live project or a side project. No cover letter, just three sentences on why this fits you
You'll hear from Gijs within three working days. No recruiter in between
A 45-minute intro, online or in Mijdrecht
A short practical assignment: realistic work, three hours max, in your own time, AI allowed. Afterwards we discuss your choices
An in-depth conversation and an offer

Not sure if this fits you? Just give us a call: +31 (0)85 488 53 90, or email Gijs at gijs@daysix.nl.

Apply for this position

You will hear from us within a few days. You talk directly to the team, not to a recruiter.