Software Engineer

I turn business ideas and challenges into working products.

I build web applications and automations - from needs analysis through development to launch.

Tell me what you want to build See my work

Portrait of Sebastian Siejek, Software Engineer

9+years of commercial experience

50,000+people use the SaaS I help develop

100+web projects delivered

End to endfrom architecture to deployment

Selected work

Independent products and commercial delivery. Each project answers a concrete problem, not a technology trend.

Independent product

Upominkly

Gift lists for events that help people buy useful presents without duplication or awkward coordination.

Read the case study

E-commerce delivery

Not Bad Studio

A smooth migration of a live WooCommerce store and implementation of its new version from a supplied Figma design.

Read the case study

Technical experiment

Daily Standup

How I combined Jira and TimeCamp data so preparing a status no longer meant reconstructing the previous day by hand.

Read in Polish

Ways to work together

Technology directed by the business goal.

I help teams move from an unclear problem to a solution they can launch, measure and continue developing.

Web applications and MVPs

I design the architecture, interface and delivery process. The scope is lean enough to validate quickly without creating fragile foundations.

Process automation and AI

I connect systems, organise data flows and remove repetitive work. I use AI where it creates a measurable advantage.

I also deliver websites and online stores, including WordPress and WooCommerce projects. I can assess ideas from a technical perspective, conduct audits, and improve performance and on-page SEO.

How I work

A clear process, regular communication and decisions recorded before they turn into expensive changes.

Discover
I clarify the problem, who we're solving it for, and the outcome we want to achieve.
Scope and proposal
I turn the work into a concrete scope, price and delivery plan.
Build
I deliver in stages, show progress and test the riskiest assumptions early.
Launch
I deploy, verify production and hand over a solution ready to evolve.

I connect product thinking, architecture and delivery.

I am a Software Engineer with over 9 years of commercial experience. I began with bespoke websites and stores, then led a team and developed React and Next.js applications. Today I work on the architecture of a SaaS product used by more than 50,000 people.

I do my best work where problem analysis, architectural decisions and pragmatic delivery need to meet. I use AI both in software development and to automate everyday work.

Full experience on LinkedIn

Latest writing

Notes from practice on automation, developer tools and decisions that simplify everyday work.

Articles in Polish

Automating daily stand-ups

How I combined Jira and TimeCamp data so preparing a status no longer meant reconstructing the previous day by hand.

Read in Polish

View all articles

New project

Tell me what you want to build.

Describe the problem you want to solve. I will reply with questions or a suggested next step.