JanstechApps Websites, apps and backends
Language

Independent software developer · Finland

Websites, Android apps and the systems behind them

One developer in Finland: business websites, published Android apps, and the backends and integrations behind them — from design and implementation through deployment and maintenance.

What I build Get in touch

Areas of work

  1. Websites WordPress and custom
  2. Android applications On Google Play
  3. Backend and integrations APIs and data
  4. AI features Where it helps

Four apps on Google Play, and the first customer website below.

Services

What I build

Four areas that usually turn up in the same project: a website needs somewhere to run and a form that actually delivers, and an app needs something behind it.

  1. Websites

    Responsive business sites with a clear structure, fast pages and accessible markup. WordPress with a custom theme when the content has to be edited by its owner, hand-built when it does not.

  2. Android applications

    Native Android in Kotlin, taken to production: navigation, background work and offline behaviour, plus the Play release, the store listing and the data-safety declarations that come with it.

  3. Backend and integrations

    APIs, databases, sign-in and the third-party services a site or an app depends on: storage, backups and the server-side parts that still have to work a year later.

  4. AI features

    AI where it does concrete work: drafting a training programme, reading an ingredient list, finding what a search box cannot. In when it earns its place in the feature list, out when it does not.

Selected work

Customer projects

Website work built for a customer and handed over to them: design and implementation first, then deployment and maintenance.

  1. Business website

    Tmi Piikula

    Website for a massage and wellbeing business in Jämsänkoski: treatments, pricing and the practical information customers look for before getting in touch, with discoverability and local search visibility considered from the start.

    • WordPress on a custom Kadence child theme
    • Custom templates for the treatment and pricing pages
    • Per-treatment detail pages and a Soluni partner shop integration
    • Privacy, mobile-first design, technical SEO, search-friendly content structure, Google Search Console readiness, and a production environment hardened for performance and security
    Platform
    WordPress
    Scope
    Design to maintenance
    Visit piikula.fi

Apps

Four published Android apps

The brand's own products, published under the JanstechApps name. Each app has its own page with the full feature list and, where they exist, screenshots. Privacy, support, terms and data deletion pages are published per app.

  2. Internet radio

    WaveIQ Radio

    Find internet radio stations that fit your taste, save them, and find them again later.

    • Playback with saved stations and favourites
    • Search by name, genre, country or language
    • AI-assisted search and similar stations
    • Google Drive backup and restore
    Platform
    Android
    Availability
    Google Play
    See what it does Open in Google Play

  3. Training & progress

    GainsAI

    Plan a training block, log the sets you actually complete, and read where your training is going.

    • AI-assisted programs and a saved program library
    • Workout logging, history and estimated 1RM trends
    • Progress analysis, body metrics and weekly check-ins
    • GainsAI Coach, meal plans and Pro Drive backup
    Platform
    Android
    Availability
    Google Play
    See what it does Open in Google Play

  4. Job search

    Työtori

    Search Finnish job boards, prepare the application and its attachments, and keep track of what you have already sent.

    • Five job boards, plus a link or posting text you add yourself
    • Application deadlines and an indicative suitability estimate
    • Application drafts, letter and CV as PDFs, and form help
    • Review period tracking — you always send the application yourself
    Platform
    Android
    Availability
    Google Play
    See what it does Open in Google Play

Approach

How I work

Four things that stay the same from one project to the next.

  1. Every project starts from a real task

    A shopping list you use while standing in the shop. A price a customer has to find on a phone in ten seconds. A session you need to log before you forget it. The feature list follows the task, not the other way round.

  2. Built for the platform, not adapted to it

    On Android that means navigation, local reminders, background playback and offline behaviour built against the platform the apps actually run on. On the web it means markup that works with a keyboard and a screen reader, and pages that still load on a slow connection.

  3. Only the data the job needs

    Every stored field, script and cookie has to justify itself. Core use in Shopping List & Notes and WaveIQ Radio runs from data kept on the device. Online services are used where the feature needs them: AI tools, shared lists, recommendations, backup and the account-linked parts of GainsAI. Työtori is the honest exception: job searching needs an account and a server, and its own page says so.

  4. Documented, not only published

    Every app has its own privacy policy, terms, support page and data deletion instructions on this site, in Finnish and English, maintained alongside the app itself. A customer project is handed over the same way: what runs where, and what keeping it running involves.

Developer

Jan Sarivuo

JanstechApps is the software and digital-services brand of Jan Sarivuo, an independent developer in Finland. The work covers websites, Android applications and the backend systems behind them: the same person designs the project, writes the code, publishes it and answers the mail afterwards.

That is also why projects stay tightly scoped: everything in them has to be worth maintaining.

Developer portfolio janstech.apps@gmail.com

Need a website, app or backend system?

I build modern business websites as well as Android applications, backends and integrations. Tell me briefly what the project needs to do and roughly when you would like it completed. Email is the fastest way to reach me.

Tell me about your project How I work