Karol Leszczyński Build & Develop PL

Services

Everything I do online — from the first conversation to maintenance.

I do all of it myself: I design, code, set up the server and answer the phone when something stops working. The prices below are starting points; I give the exact figure after a conversation, once I know the scope.

Websites

A company website, landing page or blog — built for the one job that matters: bringing in inquiries.

  • visual design made for your company
  • copy written together with the page layout
  • light and dark theme, works on the phone
  • forms, email, map, price list
  • SEO built into the structure and a 90+ PageSpeed target
  • cookie consent and a privacy policy

A dozen-plus company sites and blogs — including torweb.pl, kurs-copywritingu.pl and project-design.pl. I also run my own site-building system (sitario.com), so a simple site comes together in a few hours — hence this price.

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project from 1,500 zł

Online stores

A catalog, a search box that understands your industry, and a cart that leads to payment in a few steps.

  • catalog with filters and product pages
  • search that understands technical queries
  • product configurator with live pricing
  • integration with warehouse and wholesale systems
  • payments, shipping, invoices
  • migration from WooCommerce or Shoper

silniki-elektryczne.com.pl — 2,300+ products and a search box that understands “4kW 1400rpm SEW”. mekra.pl — a made-to-measure furniture-front configurator that prices orders from the live price list.

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project from 4,999 zł

Web applications

A tool where your customers create an account and get work done — with payments and a client panel.

  • accounts, roles, client panel
  • payments and subscriptions, balances, refunds on failure
  • job queues — long operations run in the background, not in the browser
  • an admin panel with numbers you actually look at
  • API and webhooks when the product needs to talk to other systems
  • backups and monitoring from day one

matury-online.pl, smart-copy.ai, cytado.com — all with payments, queues and real users.

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project from 15,000 zł

Mobile apps

A phone app connected to the same backend as your website: customers sign in to one account in both places.

  • React Native — one codebase for Android and iOS
  • push notifications and offline mode
  • in-app payments
  • Google Play release including store review
  • the terms of service and privacy policy the store requires
  • a PWA when a store app is not needed yet

Matury Online and Sitario on Google Play — both running on the same backend as their browser versions.

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project from 30,000 zł

Automation and integrations

The things you do by hand every Monday can usually be done once and forgotten.

  • Zapier, n8n, Make or a custom script, whichever comes out cheaper
  • warehouse, CRM and accounting kept in sync
  • reports and invoices that send themselves
  • content published without manual copy-pasting
  • scheduled jobs with an alert when something fails
  • a public API and webhooks for your product

Smart-Copy exposes a public API and runs in Zapier, n8n and WordPress. My servers run dozens of scheduled jobs with watchdogs.

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project from 3,000 zł

AI implementation

AI wired into your company's daily work, with the cost known down to the penny.

  • content generated and graded against your criteria
  • work on your documents: research, summaries, answers from sources
  • answers with the source attached, so they can be verified
  • images and voiceover when the content goes beyond text
  • per-call cost accounting and limits, so the bill never surprises you
  • a queue and automatic refunds when a generation fails

Essay grading against official exam criteria in Matury Online. Cytado pins every citation to a real page number in the source.

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project from 5,000 zł

Infrastructure and maintenance

Care for what already runs: a store, an application, or a site inherited from another developer.

  • AWS servers, certificates, configuration sized to real traffic
  • domains and DNS, renewals watched automatically
  • company email and transactional sending with SPF, DKIM and DMARC
  • daily backups and monitoring every few minutes
  • updates and migrations with no downtime
  • taking over a site from another developer

70+ domains under ongoing care. Static sites I build myself come with hosting and a certificate included in the build price — the subscription starts where a server, a database, or someone else's code to clean up comes into play.

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subscription from 150 zł / mo.

Process

The same process for a company website and for an app with payments.

  1. 01

    A conversation

    Fifteen minutes about what should happen after launch. If I can see a simpler or cheaper way to do it, I say so right away.

  2. 02

    Quote

    The scope written out point by point, one price for the whole job, and a deadline I keep.

  3. 03

    Build

    You work on a live address from the first week and watch the progress as it happens.

  4. 04

    Release

    Launch on your domain, and where needed — passing review on Google Play, the Chrome Web Store or the Zapier directory.

  5. 05

    Care

    Backups, monitoring, updates and further development. Several of my projects have run this way for years.

Contact

Tell me what you need built.

I handle the whole thing end to end: application, infrastructure, store and directory releases, maintenance. I usually reply the same day — a short, specific message works best, even if it is one paragraph and the question “can this be done cheaper?”.