Przemysław Zalewski

For authors of a SaaS or an app who need a partner

A business partner for your SaaS or app

You built it on evenings and weekends, maybe with Claude or Lovable. It works, and now come the parts nobody warned you about: payments, app stores, the first paying users, what to build next. I have shipped products since 2009 and I can join you, as a possible co-founder or for a fixed fee.

See price and start date →

Przemysław Zalewski

Three ways to work together

Equity

For a product with users and a plan. I become a co-founder with vesting, so we both keep what we earn by working.

A share of revenue

No company needed yet. I take a percentage of revenue for the work I put in, written down with a cap and an exit.

A contract

The plain option: hours at the rate in the configurator, no strings. Often the right start before anyone talks about equity.

What I bring

Architecture and code, payments and subscriptions, App Store and Google Play, analytics, and honest calls on what to cut.

How it works

  1. A call about the product

    What it does, who uses it, who pays, what you need. If I am not the right partner, I say so.

  2. A small piece together

    A few hours on one real problem, so we both see how the other works before signing anything.

  3. The agreement

    Equity, a share or a contract, with what each of us does, how decisions are made and how either of us can leave.

  4. A review after three months

    On the numbers: users, revenue, time spent. Then we keep going, change the deal or part as friends.

Where it fits

  • A SaaS or an app built as a side project, with the first users asking for more.
  • A product built with Claude, Lovable or Bolt that needs an engineer who has run one in production.
  • An app ready for the App Store or Google Play that nobody has published yet.

Proof

I was the founding engineer of Sandtime.io, a time-tracking SaaS with Paddle and Mac App Store subscriptions on eight platforms, in production since 2018. Before that I published 25+ apps with 3.7M+ downloads. Check your own case in the free multi-tenant calculator.

Sandtime.io: founding engineer, eight platforms, one codebase

The problem
A time-tracking SaaS had to live where people work: desktop tray, browser, phone and app stores.
What I did
I authored the original product vision and architecture in 2018 and made the first commit. React Native wrappers for iOS and Android, Electron for macOS, Windows and Linux, a Chrome extension, multi-tenant routing, SSO, Dockerized services, Paddle and Mac App Store subscriptions, CI/CD.
Result
Eight platforms shipped and run in production. The only engineer active in every year of the product, 8,000+ commits and close to half of all merges to trunk.

8 platforms 8,000+ commits since 2018 Open ↗

Taking over growth: SEO, GEO and dashboards leadership reads

The problem
Organic acquisition was close to zero and nobody could say which feature moved which number.
What I did
A tracking plan per feature, PostHog KPI dashboards, SEO and GEO work on landing pages and help, with help, changelog and landing pages treated as one body of context for people and bots.
Result
Organic acquisition grew from near zero and leadership gets its numbers from dashboards, not from asking. Numbers stay relative on purpose.

PostHog SEO + GEO

25+ apps, 3.7M+ downloads, published worldwide

The problem
Between 2009 and 2017 the Windows Phone and Windows Store ecosystem needed apps and had few developers.
What I did
C#, XAML and ASP.NET. Localization into dozens of languages, store listings, ads and in-app monetization, client apps for Polish media brands, plus game development on PC and Xbox 360 before that. Before Windows Phone 7 allowed background tasks, my Gadu-Gadu client kept receiving messages by running as a background audio agent: whenever the audio stream asked for more data, it polled the chat servers and returned silence. Later a push proxy on my own server replaced the hack.
Result
25+ apps and 3.7M+ downloads. My Gadu-Gadu client was the most downloaded app on the Polish Windows Phone Marketplace in its first week, and its successor Pogaduszki won its category at AppAward 2013 out of 300 entries. The habit of shipping, watching users and fixing what they say started here.

25+ apps 3.7M+ downloads

A business partner for your SaaS or app

You built a SaaS or an app and need someone who has shipped products before. I join as a business partner: for equity, a share of revenue or a plain contract, picked on your numbers.

See price and start date → Book a free 30-min call

FAQ

Questions

Will you work for equity?
Sometimes. Equity or a share of revenue only where there are users or paying clients and a plan to sell. Before that a contract is the honest option, and we can switch later.
I have no company. Can you sell it on yours?
Not as a start. Selling as the company of record comes with taxes, liability and data agreements, and it makes sense once revenue is real. Until then we pick a simple setup with an accountant.
What does a contract cost?
The rate in the configurator, the same as for my other work. A mix works too: a lower rate plus a share of revenue.
What if it does not work out?
The agreement says how either of us can leave from day one. Equity vests over time, so nobody keeps what they did not earn.
My project is small. Can you just help?
One small project a month, a few hours, for free or in exchange for a reference: a public review and permission to show the project as a case study.

Let’s find out in 30 minutes

A free 30-minute call. You bring the problem, I bring questions. Want a number first? The configurator shows hours, a price range and the start date.

If I am the wrong person I will say so on the call and point you to someone better.

or write to ciunkos@gmail.com

After you book: a calendar invite, then the call. Nothing else to fill in.

Calls this week · work starts 2 November 2026 · B2B contract or employment · Wrocław, Poland (CET), remote