# Croozer App - Digital Product Passport for Bicycle Trailers

> The Croozer App uses blockchain technology to create a digital product passport for bicycle trailers. Through QR codes on the trailers, users can securely document and verify all maintenance, repairs, modifications and resales via smart contracts. The system enables buyers to transparently view the complete maintenance history and number of previous owners.

**Sector:** Secondary sector · **Industry:** Mechanical and plant engineering · **Organisation:** Croozer · **Maturity level:** Concept

Canonical URL: https://www.sapientblock.com/en/use-cases/croozer-produktnutzung-transparent-dokumentieren

## Documentation status

- **Project status:** Concept
- **Evidence:** Evidence medium
- **Editorial review:** Ufuk Avci, 15 April 2026

## Description

The Blockchain Reallabor Huerth cooperated with Croozer GmbH (Cologne), one of the leading European manufacturers of bicycle trailers and jogging strollers. The jointly developed blockchain app records product usage data immutably: every trip, mileage, and load situations.

Croozer bicycle trailers are used intensively over many years. The problem for manufacturers: how long and under what conditions a product was actually used is unknown — this complicates product improvements, warranty assessments, and sustainability statements. The blockchain app solves this: users voluntarily track their trips via GPS; the aggregated usage data (mileage, terrain type, average speed, weight load) are blockchain-documented. For users: proof of use as a basis for extended warranty claims or as sustainability evidence. For Croozer: anonymised aggregate data help to prioritise product improvements based on data. The IFAA (Institute for Applied Labour Science) presented the Croozer blockchain cooperation at the 2025 colloquium as an industry example of usage-based product documentation. Fraunhofer FIT published the use case in the Blockchain Reallabor portfolio.

## Benefits

- Manufacturers receive valuable data about the actual use of their products for product development.
- Consumers can make informed decisions when buying used products based on complete maintenance histories.
- The blockchain-based documentation creates immutable and transparent product histories.
- Buyers receive complete insight into maintenance history and ownership for the first time.
- The system can extend the lifespan of products through better maintenance documentation.
- Service technicians can digitally document their work and thereby demonstrate their professionalism.

## Challenges

- Companies must digitise their service processes and train employees accordingly.
- Acceptance and consistent use by all parties in the service chain must be ensured.
- Integration into existing business processes of manufacturers and service partners requires adjustments.
- Service technicians must learn new digital documentation processes and integrate them into their existing workflows.

## Technology foundation

The application is based on blockchain technology with smart contracts that enable immutable and transparent storage of all product-related data. The combination of QR codes as a physical interface and the blockchain as a data store creates a secure link between the physical product and its digital information.

## Sources

- [Blockchain-Reallabor - Croozer App](https://blockchain-reallabor.de/portfolio-item/croozer-app/)
- [IFAA Kolloquium 2025 - Marktplatz](https://www.arbeitswissenschaft.net/angebote-produkte/veranstaltungen/va-ifaa-kolloquium-2025/marktplatz)