App & AI studio · Oslo
Tennnis is a two-person studio in Oslo. We design and build apps for iPhone, Android and desktop, websites and AI tools at a fixed price agreed before we start, and you can click through a working version in week one.
Dumb phone. Same phone.
Selected work
Every product here was designed, built and launched by Tennnis. It is where we test our methods before a client pays for them.
The pocket FM groovebox
A four-operator FM synth and a four-track step sequencer, drawn like a handheld game cartridge. It opens on a song made entirely in it: press play, then take it apart.
Native on both sides. SwiftUI on iPhone and iPad, Jetpack Compose over a C++ port of the same audio engine on Android, with the same sounds and the same project files.
A journal that hands your proof back.
Bedtime stories starring your child.
A pocket cassette looper.
AI coding agents, side by side.
Cinematic captions for iPhone video.
Smarter home hunting in Norway.
People scrapbook their kids and their holidays, so nothing could go to a server. Subject cutouts run on Apple's on-device vision stack, and there is no account, no upload and no infrastructure bill.
What we build for you
Scope is a numbered list of screens, priced before we start. Strike a line out and watch the number drop.
Marketing sites, booking flows, customer portals, internal tools, and desktop apps for Mac and Linux. Hosted and monitored, and editable by your own people.
Native Swift and SwiftUI, on-device AI included, with Android in Kotlin alongside. Seven apps through App Store review, so launch holds no surprises.
Half a day to map where AI actually fits in your operation, then a build. Agents, document and support workflows, and training so it sticks.
All prices ex. VAT. Your fixed price is set on a free 45-minute scoping call. Care plans from 1 500 kr a month, cancel any month.
How a project runs
One shared thread and a new build every few days, so you always know where the project stands.
45 minutes. You leave with a screen list and a fixed price, or an honest no.
A version you can click through. We correct course from real screens while changes are still cheap.
A new build every few days in one shared thread, so you always know where the project stands.
Hosting, monitoring and small changes on a monthly plan. Cancel any month.
The studio
At Tennnis, the people who scope your project are the people who build it. The quote is a real number, and the answer to a question on a Tuesday afternoon comes from someone who wrote the code.
Rally · notes from the studio
On-device AI runs on your phone's own chip, so what you type or photograph never leaves it. Since iOS 27, "built with Apple's AI" no longer guarantees that. How to tell, and how to choose.
Read →Before you open source a side project you built for yourself, run it on a machine that has never seen your setup. What open sourcing Agency took, from logs and signing to a Linux port.
Read →Give every agent its own git worktree and branch, then review each diff before you merge. The steps by hand, what Claude Code, Codex and Cursor automate, and the traps.
Read →Tell us what you want to build and roughly what you can spend. If it is not a fit we will say so on the first call and point you somewhere better.
hello@tennnis.no
