API and integrations developerAvailable now
APIs and integrations that make the product actually work.
Behind every web and mobile product is a layer of APIs, databases and integrations that nobody sees until it breaks. I design and build that layer in Node.js and TypeScript: REST APIs, SQL schemas, authentication, payments, accounting and the third-party services your product depends on.
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Is this a fit?
An honest fit check before we talk
I would rather tell you no on the first call than waste your budget. Here is what a good match looks like for this kind of work.
A good fit if
- Your web or mobile app needs a backend API and you want one developer who can build both sides.
- You need to integrate payments, accounting, CRM, authentication or another third-party service properly.
- You have an API that has grown organically and needs structure, documentation and tests.
- You want someone who has worked on data-heavy fintech and e-commerce products before.
Probably not a fit if
- You need GraphQL specifically. I build and consume REST APIs.
- You need large-scale data engineering, machine learning or infrastructure-only work.
- You are looking for a team of backend engineers rather than one senior full-stack developer.
What I do
What the engagement typically covers
- REST API design and build
- Resource design, validation, error handling, pagination, versioning and documentation. Node.js, TypeScript and a SQL database.
- Third-party integrations
- Payments such as Stripe, accounting systems, authentication providers, email and webhooks. Built with retries, idempotency and logging so they survive contact with reality.
- Database design
- Schemas, migrations, indexes and queries that stay fast as the data grows, with backups and access you can audit.
- Auth and security basics
- Authentication, roles and permissions, secrets handling, rate limiting and input validation. Done as standard, not as an afterthought.
Proof
Clients who kept me around
APIs and data layers I have built in climate tech, construction software and a startup I co-owned.
Målbar
Full-Stack Developer · Freelance
Ongoing development for a Danish life cycle assessment company. I have helped build their LCA screening tool, which lets companies estimate the climate footprint of their products, along with the internal tooling the team runs on every day.
Read the case studyBunch Bygningsfysik
Full-Stack Developer · Freelance
Ongoing development since 2021 for a Danish building physics consultancy. I built their moisture content calculator for construction compositions, keeping the existing calculation module with years of expertise baked in as the engine and putting a modern, easy to use web UI on top, and I have kept developing and maintaining it since.
Read the case studyeManager
Full-Stack Developer & Partner · Full-time
Co-built an esports tournament platform with a fantasy manager game from the ground up: product decisions, architecture and code, as a partner in the company.
Read the case study
Process
How we'll work together
The same four steps for a two-day fix and a two-year engagement.
Intro call
A free 30-minute call where you tell me about your project, goals and constraints. I ask a lot of questions and tell you honestly whether I'm the right fit.
Proposal & estimate
You get a short written proposal: scope, approach, timeline and price. Fixed price for well-defined projects, hourly or retainer for ongoing work.
Build in the open
Short iterations, working software early, and a weekly update you can actually read. You see progress and can change course before it gets expensive.
Launch & support
I handle deployment, hand over clean documentation, and stick around for support and further development if you want me to.
FAQ
Questions I get asked
- Which backend stack do you use?
- Node.js with TypeScript, REST APIs, SQL databases such as PostgreSQL, and hosting on Vercel or your cloud of choice. If your backend is in another language, I integrate with it from the frontend and mobile side.
- Can you integrate with our accounting or ERP system?
- Very likely. I have worked inside accounting software and on the frontend of a bookkeeping automation product for e-commerce. Most systems expose a REST API or webhooks, and I will check the specifics on the intro call.
- How do you price work?
- Fixed price for well-defined projects, hourly or a monthly retainer for ongoing work. My preferred engagement is 20-40 hours a week for six months or more. Rates are in the proposal, not on the site, because they depend on the scope.
- How quickly can you start?
- I keep my availability status up to date on the homepage. If it says available, I can usually start within one to two weeks. The first step is a free 30-minute intro call.
- Is one developer a risk for us?
- Code lives in your repositories from day one, written so the next developer can pick it up. Documentation and handover are part of every engagement, not an extra. My track record is long tenures, which is continuity, not dependency.
- Do you work with companies outside Denmark?
- Yes. Most of my work is remote. I am in the Central European timezone, which gives full overlap with Europe and the UK and 3-6 hours of overlap with the US East and Central timezones. I work async-first with a written weekly update.
Tell me what you are building
What it is, roughly when it needs to exist, and what a great result looks like. I usually reply within a day, and the first 30-minute call is free.