Websites & web apps
From landing pages to SaaS platforms. React, Next.js, Python — we choose the stack based on needs, not trends.
SISL.PL — boutique web studio in Poland: custom websites, online stores and technical SEO
// independent // studio // web //
An independent web studio from Poznań. Custom websites, online stores and integrations that work, attract and earn.
// FOR INTERNATIONAL CLIENTS
Why hire a Polish boutique dev studio for your project?
- → Same time zone as Western Europe. Warsaw is GMT+1/+2 — overlaps every working hour with Berlin, Amsterdam, Paris, London. No 3 AM Slack pings, no async-only workflows.
- → EU-native (GDPR, ePrivacy, DSA). We've built and shipped under the same regulatory framework as your German/French/Dutch business. No "we'll figure it out" stage on cookie consent, data residency, lawful basis.
- → Western-grade engineering at a Polish rate. Senior dev day-rate sits at 35–45% of equivalent Berlin/Amsterdam rates without sacrificing English fluency, code review discipline, or test coverage.
- → Boutique, not body-shop. Every project goes through one senior who owns the full stack — not a 5-person "team" where the lead is on three other projects. You always talk to the person who writes the code.
- → Modern stack, no fragile WordPress glue. FastAPI, Next.js, Astro, Magento for e-commerce, Postgres + Redis, Docker-first deploys. Same toolbox we use for our own products (live: sisl.pl/battlemap) — proven on real production traffic, not just demo decks.
Invoicing in EUR or USD on request. NDA + IP assignment template available. Standard contract: monthly retainer or fixed scope; 50/50 milestone split for projects above EUR 5,000.
2
plugins in the WordPress.org directory
5
years of experience
1
person runs your project, no middlemen
<24h
response time
// services
What we do best
Every project starts with understanding your business. The best website is one that works for your success.
UI/UX Design
Interfaces that are beautiful and intuitive. Every pixel has a purpose — guiding users to action.
E-commerce
Online stores that sell. Payments, logistics, management panels — turnkey solutions.
SEO & Optimization
Your website can be a masterpiece, but without traffic it’s an empty gallery. Visibility from day one.
Automation
Bots, API integrations, dashboards. We automate repetitive tasks.
Maintenance & support
We don’t disappear after launch. We monitor, update, and grow.
// process
From idea to launch
Transparent process, regular communication, zero surprises.
01
Discovery
We talk about business, goals, and target audience. We define the scope.
02
Design
Wireframes and prototypes. We iterate until it’s just right.
03
Build
Clean code, tests, code review. We show progress regularly.
04
Launch
Deployment, monitoring, training. Then ongoing care and growth.
// projects
Selected work
Every project is a different story. What they share — clients who come back.
Business site
Scrutarius — antiques buyer
Lead-gen site for a watch & antiques buyer. Victorian brand with a live clock in the logo, local SEO and a 59 KB first paint.
Business site
POLMAR — firewood
Site for a firewood seller: pricing, phone orders, delivery range and trust sections (13 years, honest volume). Built for fast contact and conversion.
Web app
Co mam zjeść? — food map
Interactive map and ranking of eateries reviewed by YouTubers — 1048 spots, filters by cuisine, city and rating, plus 'near me' search. Built with SISL.
Web Application / Data Platform
SISL Battle Map: Real-Time Conflict Data Platform
Real-time interactive conflict map aggregating 270+ daily events from 10 regions. Features custom 4-language translation engine, historical backfill, and a performant freemium API for OSINT analysts, journalists, and fintechs. Built with FastAPI & PWA.
Web app
mockql
MockQL is a hosted GraphQL mock server that turns any SDL schema into a live endpoint in one click — no backend setup, no resolver boilerplate, no fixtures. An AST-driven engine infers behavior for every type (scalars, objects, lists, enums, unions, interfaces, recursive references) directly from the schema, with deterministic fake data from @faker-js/faker
Web app
PgX-Ray - Postgres EXPLAIN Visualiser
A client-side visualiser for Postgres EXPLAIN (ANALYZE, FORMAT JSON) plans — paste the JSON, get an interactive graph with heatmap-coloured hotspots and automatic "Smart Insights" that flag sequential scans, row-estimate drift, Nested Loop explosions and work_mem spills. Runs entirely in the browser — no data leaves the tab. Next.js 14 (static export), React Flow, strict TypeScript, Zustand, Tailwind; EN/PL with locale-aware number formatting; 120 tests across parser, rule engine, XSS surface, determinism and dictionary parity.
Web app
Hookzy
Check if your webhook works
// from_the_blog.sh
Last from the journal
Articles on web development, e-commerce, SEO and the small bets that work for Polish businesses.
The WooCommerce Loyalty Points Plugin That Doesn't Lose Points
Loyalty plugins that lose points, break on the Blocks checkout, or lock you into a subscription. What to check, and the trustworthy-ledger approach that fixes i…
Polish SEO Agency: A Pragmatic Guide for US/UK/DE
Considering a Polish SEO agency for your US, UK or German business? A pragmatic guide to the benefits, costs, red flags, and how to vet a boutique Polish SEO co…
SEO Copywriting Services in Poland — English & Polish
SEO copywriting is writing that ranks in Google and makes a human act. What SEO copywriting services in Poland should deliver — in English and Polish — and how …
// scanner.sh
Check your store.
Free.
Enter an address and in ~30 seconds see what your Magento 2 exposes publicly: files that should not be reachable, security headers, technical SEO and performance measured on real users (Chrome UX Report). No login, nothing to install in the store — only what every visitor can already see.
Run a free scan// pricing.sh
Pricing — on the table.
All prices net (VAT 23%), fixed-price for defined scope. Final quote in 24h after brief. Subscription for small biz, fixed projects for everything else.
subscription / monthly
Your site. On a subscription.
from 300 zł ≈ €69 / month, all included
* First month: +500 zł (≈ €115) one-time setup fee
For small local businesses — auto shops, beauty salons, plumbers, barbers. Polished site in 2 working days, then we take care of everything else forever.
- Custom design built around your brand
- Domain and hosting included
- SSL + regular backups + small edits on request
- Mobile responsive, fast, SEO-ready
- Cancel anytime — no lock-in
// fixed_price_projects.sh
// company site
Company site
from 1 490 zł ≈ €340
Up to 8 pages on WordPress without page builders, live in 7 working days. Mobile speed and copyright transfer written into the contract. Custom design from 4 900 zł (≈ €1,120).
- Lighthouse mobile ≥ 90 in the contract
- Full copyright transfer, admin access
- Hosting of your choice, no site subscription
// landing page
Landing page
from 1 500 zł ≈ €345
Single high-converting page for Google/Meta Ads. A/B-ready, Pixel + GA4 wired.
- Mobile-first hero + CTA
- Conversion tracking setup
- LCP < 2.5s guaranteed
// custom design
Custom-designed site
from 4 900 zł ≈ €1,120
Up to 8 pages designed from scratch, copywriting included, SEO + Schema.org. Larger sites (15-30 pages, multilang) quoted after a brief.
- Custom Figma design + WordPress / headless CMS
- Mailchimp / HubSpot / Calendly hooks
- PL + EN versions, hreflang, schema.org
// woocommerce
WooCommerce store
from 3 800 zł ≈ €870
Up to 100 SKUs, WordPress + Kadence, payment gateway, PL/EN. Store with Allegro, InPost and invoicing, up to 500 products — 4 490 zł (≈ €1,030).
- Przelewy24 / PayU / BLIK / Stripe
- Custom theme or fork of starter
- Voucher system + email automation
// magento / adobe commerce 2
Magento / Adobe Commerce 2
from 19 500 zł ≈ €4,470
Entry build from PLN 19,500. With 1k+ SKUs, multistore, B2B customer-specific pricing and ERP integration the budget grows to PLN 59,500+ (3-4 months).
- Hyvä Theme or PWA Studio (headless)
- Comarch / Subiekt / SAP integration
- Multi-currency, requisition lists, quotes
- Magento implementation → · modules → · Hyvä →
- Comarch Optima integration → · Allegro →
- support & SLA → · audit → · loss calculator →
// custom web app
Custom web app / SaaS MVP
individual quote
React/Next.js + FastAPI/Node, auth, admin panel, Stripe Billing, Postgres, Docker deploy.
- Multi-tenancy + role-based access
- Stripe Subscriptions + invoicing
- Sentry monitoring + CI/CD pipeline
// after delivery
Maintenance from 599 zł/mo ≈ €135/mo
CARE / GROWTH / PARTNER for WordPress and WooCommerce — uptime, backups, updates, security
Need something not on the list? Just ask — quote in 24h.
Got an idea?
No matter the stage — a sketch on a napkin or a full specification.
get in touch// contact
Let’s build together
Every collaboration starts with a conversation. Zero obligations.
Tell us about
your project
Fill out the form or write directly. We respond within 24 hours — usually faster.
enter ↵