Legacy frontend modernisationAvailable now
Inherited a codebase nobody wants to touch?
Releases have stopped, the site is slow, the last developer left and the dependencies are years behind. I take over stalled and legacy frontends, stabilise them, and move them forward in steps you can ship, with a written plan and no drama. I did exactly this for a building physics company, keeping their proven calculation engine and putting a modern web UI on top.
Start here
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
- You have a React, Vue, Angular or jQuery-era frontend that is hard to change and nobody on the team wants to own.
- Releases have slowed down or stopped because every change breaks something else.
- Your previous developer or agency left and you need someone to take over safely.
- You want to modernise without a full rewrite and without stopping feature work.
Probably not a fit if
- You want a complete rewrite on day one. I will usually recommend an incremental path first and show you why.
- The codebase is in a language far from JavaScript and TypeScript, for example a PHP or .NET backend rewrite. I can modernise the frontend in front of it, not replace it.
- You want someone to blame for the old code. I am more interested in fixing it.
What I do
What the engagement typically covers
- Audit and plan
- I read the code, the git history and the bug tracker, then write a short assessment: what is risky, what is fine, and what to do first. You get it in writing before any large decision.
- Stabilise
- Builds that pass, dependencies updated, tests around the scary parts, monitoring in place. Releases start flowing again.
- Modernise incrementally
- TypeScript, current framework versions, a modern build and a path from old patterns to new ones, shipped in steps alongside normal feature work.
- Performance fixes
- Slow pages, large bundles and jank, measured and fixed. Core Web Vitals you can show the business.
Proof
Clients who kept me around
Mature codebases I have taken over or kept healthy, and how long each client kept me.
Bunch Bygningsfysik
Full-Stack Developer · Freelance
Built a moisture content calculator for construction compositions. Their existing calculation module already had years of building physics expertise baked in, so I kept it as the engine and put a modern, easy to use web UI on top of it instead of rewriting what worked.
Read the case studyVisma Dinero
Frontend Developer · Full-time, then freelance
Frontend development on Dinero, one of Denmark's most popular accounting platforms for entrepreneurs and small businesses. First as an employee for four years, then they brought me back as a freelancer for two more.
Read the case studyY-mAbs Therapeutics
Full-Stack Developer · Freelance
Full-stack development of web solutions for a commercial-stage biopharmaceutical company, a regulated environment where reliability, correctness and clear documentation are not optional.
Read the case studyMålbar
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 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
- Rewrite or refactor?
- Almost always refactor and modernise incrementally. Rewrites take longer than planned, freeze feature work and often reproduce the old bugs. I will tell you honestly if your case is one of the rare exceptions.
- How do you start on a codebase you have never seen?
- With a short paid audit. One to two weeks of reading code, running it locally, talking to whoever knows it and writing down what I find. You get a document you can act on whether you hire me for the next step or not.
- Can you work alongside our existing team?
- Yes. Modernisation usually happens next to ongoing feature work. I coordinate with your team, review their changes and keep the plan updated so nobody is blocked.
- 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.
- What happens after launch?
- I stick around. Most of my clients have kept me for one to six years, first for the build and then for support and further development. A retainer of reserved weekly hours is the usual shape, but ad hoc work is fine too.
Contact
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.
hello@perhp.com