Turlo is a commission-free travel marketplace app: travellers search organized trips from travel agencies and guides, then contact the organizer directly. For a travel-tech client I wrote the backend, the web app, the Android app and the native 2.0 apps for iOS and Android, plus an AI import that turns a link to a tour into a complete draft listing, ready for approval.
Rafał Szewc · Software engineer in Gliwice, Poland (CET) · 12+ years, previously at SAP
Counted in the repository, October 2026.
Turlo’s organizers are small travel agencies, independent guides and Polish-speaking operators abroad. Each of them published tours only on its own website, usually in one language and in its own currency.
Getting listed elsewhere meant retyping every tour by hand: the itinerary, what is and isn’t included, each departure with its price and free spots, and the photos. Translation was out of reach.
To compare dates and prices, they opened one agency site after another, with PLN, EUR and USD side by side. The big booking platforms solve that, but they charge a commission.
Run by hand, the catalogue would mean approving every listing, syncing 16 language versions after each edit, collecting reviews only from real participants and feeding social media.
Six modules on one backend. The web app and both store apps share one Spring Boot API; organizers and the operator work in web panels.
A traveller types a sentence instead of setting filters. gpt-4o-mini pulls out the destination, budget, dates and trip length. Elasticsearch then matches the text, allows one typo and re-ranks the results by meaning.
Italy in October under $3000
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An organizer pastes links to tours on their own website, one per line. A headless browser screenshots each page and collects text and photos. GPT-4o vision turns that into an offer with the itinerary, departures, prices and inclusions, which stays inactive until approved.
gpt-4o-mini translates each offer into 15 more languages and, after an edit, only the fields that changed. Each language gets its own search index, URLs and sitemap. Prices stay in the organizer’s currency, with an approximate conversion at the daily National Bank of Poland rate.
The operator connects one Meta account for Facebook and Instagram. GPT-4o drafts each post and gpt-image-1 makes three images. Scheduled slots publish on their own or wait for the operator’s approval.
New offers wait for approval, and an edit sends a live offer back only if its content changed. While a change is copied to the other 15 languages, the offer is locked. Review links go only to people who enquired about a departure that has ended, and every review is moderated.
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An enquiry carries the departure, group size and preferred contact, and goes by e-mail straight to the organizer. Turlo takes no payment and no commission. The 2.0 apps, SwiftUI on iOS and Jetpack Compose on Android, share the web’s API and translations.
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Real listings as of September 2026: the organizer’s Polish title, and the English title Turlo generated from it.
Hola Dominikana
Perła Dominikany - Wyspa Saona
ENPearl of the Dominican Republic - Saona Island
7–28 Nov 2026, 4 dates
from$145
Mozaika Tours
ANDALUZJA Semana Santa na południu Hiszpanii
ENANDALUSIA Semana Santa in southern Spain
19–24 Mar 2027, 6 days
€1,420
ADBER
Podróż przez tysiąclecia
ENJourney Through the Millennia
5 Oct and 5 Dec 2026, 12 days
fromPLN 9,500
One Spring Boot 3.5 backend on Java 21, built with DDD and CQRS, serves all three apps. Writes go to MySQL; searches read from Elasticsearch, which holds every offer in all 16 languages.
REST API: v2 for the web and the 2.0 apps, v1 frozen for installed 1.x apps
On the server, in Docker Compose
Cloud services
The AI steps call OpenAI’s API in the cloud and see listing content and search phrases. Enquiries, with travellers’ names and e-mail addresses, never pass through a model: Mailgun e-mails them straight to the organizer.
The backend has four tiers of tests, and golden-file tests freeze the v1 API. A contract test checks the Angular models against the Java DTOs, and 26 Playwright specs test the web end to end.
From the first commit on 13 September 2025 to the 2.0 apps in September 2026.
Sept – Oct 2025
Offers, departures, itineraries and inclusions in MySQL, organizer accounts and enquiries.
Dec 2025 – Jan 2026
Reading offers from organizers’ pages, and Facebook and Instagram posts with generated images.
Feb – Mar 2026
Web panels, Elasticsearch search, link import, 16 languages, currencies, the sentence parser and the Android app.
Apr – Jul 2026
Maintenance, the social-media scheduler, and the iOS app added to the same repository.
Aug 2026
A search-first site for travellers: home, offer and organizer pages, localized URLs and sitemaps.
Sept 2026
Reviews, saved trips, destination pages, end-to-end tests, the native 2.0 apps and bulk import for the operator.
Checked before the 2.0 release
A clean re-run of every build and test of version 2.0, 22 September 2026.
The price follows the scope, and Turlo’s scope (a backend, a web app, two native apps and the AI pipeline) grew in stages over twelve months. Most projects start smaller: a proof of concept on your data costs PLN 10,000–25,000 net (≈ €2,300–5,700) and takes 2–4 weeks, and a system built on your company’s data is usually PLN 40,000–120,000 net (≈ €9,100–27,400) over 2–3 months. Euro amounts use the NBP mid rate of 9 Oct 2026 (1 EUR = 4.3775 PLN), rounded. For the full breakdown, read How much does it cost to build an app in Poland? Real budgets for 2026.
A focused first version usually takes 2–3 months. Turlo, by contrast, grew in stages over twelve months: the backend first, then the AI import, search and translations, and the native 2.0 apps last.
It can be, if you decide early what the model may see. Turlo sends OpenAI listing content and search phrases, never enquiries, and keeps photos on AWS S3 in Frankfurt (eu-central-1). When the data is confidential, I run local models on the client’s own server; Turlo’s embedding step can already switch to one under Ollama.
Yes. Turlo talks to OpenAI, Mailgun, AWS S3, Meta and the National Bank of Poland, and its import reads organizers’ websites that have no API. If you run an ERP such as Comarch ERP, SAP or IFS, I connect to it through its API or SQL views. We agree the scope of the connection on the first call.
No. Installed 1.x apps still use a frozen v1 API, and contract tests fail the build if a v1 response changes. New features ship under v2.
Tell me what your product should do. You talk to me, the engineer who writes the code, and I reply within one business hour on WhatsApp.
