Kristóf Karner

Kristóf Karner is an independent web developer in Budapest, working with small and medium businesses. I build and maintain business-critical web systems — the part that takes the booking, processes the payment, sends out the notification, and stays my responsibility after launch. WHAT I BUILDBooking and scheduling systems. Stripe-based payments and subscriptions. Telegram messaging and access automation. Invoicing integrations, including Hungarian fiscal invoicing. Custom backend work, where the tools a business already uses have to be connected so the process runs without manual steps. Alongside that: website maintenance on a monthly retainer — updates, backups, fixes and smaller changes — and Google Ads campaign management. HOW I WORKEverything stays in one pair of hands. There is no project manager and no handover between developers: what we agree on is what I build, so there is nowhere for the information to get lost. The result is personally my reference, not a team's output with my name washed out of it. Most of my work is long-term. Maintenance and extension of systems already running, rather than one-off delivery — several clients have been with me for years. WHO I WORK WITH Small and medium businesses that need more than a template site: where payment, booking or access control has to work, and keep working afterwards. I work in Hungarian and English. WHAT I TURN DOWNWork I could not maintain afterwards. If a project needs a technology or a scale I cannot support long term, I say so rather than take it on — one person's capacity is finite. Accounts and access stay in the client's name: hosting, payment provider, invoicing service. I work in them, I do not own them. If someone else takes over one day, there is documentation to hand over.Written work on these subjects — payments, access control, email authentication — is published on my website.