monday.com app development
I'm Martijn Rozema, a software engineer based in the Netherlands. I build monday.com apps and integrations as a subcontractor for implementation partners, under your name, for your client, with a fixed scope and a delivery date.
Board and item views, widgets, integration recipes and automations built on the monday apps framework. OAuth, the GraphQL API, webhooks and the rate limits that come with them.
Connecting monday to the systems your client already runs: CRMs, internal APIs, file stores. Two-way sync, migrations and the error handling that keeps it running after go-live.
I've been through the marketplace submission process before, so I know what the review looks for before the build starts: scoped OAuth permissions, the security questionnaire, versioning, monitoring.
How we work together
Your client sees your agency. I don't approach your clients. I build it as a separate project and deliver it under your name.
I work in defined deliverables with a fixed date, not hours billed after the fact. You know what you're getting and when you can plan the demo.
Around 16 hours a week, with Friday as my project day: calls, reviews, releases. I run this alongside a permanent role, so I take on one project at a time, and what I commit to gets finished. That works well for projects with a clear scope. It doesn't work if you expect daily standups, and I'd rather say so up front than have you find out later.
Scoping, invoicing and account management stay with you. I build.
A typical week
Work
Submitted to the marketplace
Teams on monday.com that wanted a form in several languages had to build a copy of the form for each language and keep every copy in sync by hand. monday's own form builder only offers AI translation with no manual control, and it doesn't translate dropdown or status options at all.
An app that turns one monday board into a form available in as many languages as the team needs. An admin connects a board, and the app generates a draft form matching its columns; from there they translate labels, help text and the dropdown and status options per language, by hand or with AI assistance, while the original language stays visible as a reference. Respondents fill in the form in their own language; every submission lands as a single item on the same board, with a column recording which language was used.
In monday, every dropdown and status option has a fixed ID that never changes, even when someone edits the label. I tested that myself on a live board instead of blindly trusting the docs. Linking options by name or position quietly breaks as soon as an admin renames or moves one. The app therefore always links options by that fixed ID.
monday notifies apps when a column is added, but not when one is renamed, changes type or is deleted. So the app regularly checks whether the form still matches the board. If something no longer lines up, the admin sees it, instead of answers quietly ending up in the wrong column.
Sometimes a submission can't reach the board, for example when monday is briefly unavailable. The app retries a few times. If it still fails, the submission is kept with the error message, and the admin can resend it. Nothing gets lost silently.
I've been building software for 9 years and currently work as a software engineer in a permanent position. My work is mostly full-stack, in Angular and .NET.
I got into monday.com development because building on someone else's platform is its own kind of challenge. You work with their API, their interface and their constraints. Making something that feels like it belongs there is a puzzle I enjoy, even when it gets tricky. It helps that the documentation is solid and that their developer support actually answers.
Outside monday.com I take on backend and integration work in .NET, and frontend work in Angular. Have a project without monday? Feel free to ask.
Contact
Send me a short description of the project, what it should do and when it needs to be live. I'll reply within a day. If it's a fit, we'll schedule a call on a Friday and I'll come back with a scope and a price.