Sloc.it

Christoph Jentzsch entered the crypto space early, joining Ethereum in summer 2014 as a lead tester responsible for writing consensus tests to ensure all client implementations (C++, Python, Go, Rust) voted on the same rules. His theoretical physics background positioned him well to understand distributed systems. In 2015, he co-founded the DAO (Decentralized Autonomous Organization), a smart contract project that aimed to let people pool funds and collectively decide how to deploy them—the largest crowdfunding effort of its time, raising 150 million dollars worth of ether.

The DAO famously contained a bug (the re-entrance vulnerability) that allowed an attacker to steal approximately 50 million dollars. Jentzsch learned this lesson "the hard way." The community responded with a controversial hard fork of the Ethereum blockchain to return stolen funds to users, creating Ethereum Classic as a result. This experience taught him critical lessons about smart contract security and the complexities of decentralized governance.

Moving past the DAO failure, Jentzsch launched Sloc.it, focusing on the decentralized sharing economy. The core insight: enable physical IoT devices to receive payments and execute complex agreements via blockchain. The canonical example is a smart door lock that can accept payment and automatically unlock, or an EV charging station that can charge per kilowatt-hour. The system uses Ethereum smart contracts and requires no intermediary—if the founder disappeared tomorrow, the locks would still function, listening to the blockchain indefinitely.

Sloc.it partnered with a company called "no key," which manufactures Bluetooth-enabled smart padlocks. The team also integrated with electric vehicle charging stations, deploying the software on over 1,000 charging stations. The differentiation from competitors like Airbnb: the payment mechanism is embedded directly into the device itself, not dependent on centralized servers.

In February 2017 (early in the year), Sloc.it raised a $2M seed round from VC investors—notably choosing traditional venture funding rather than an ICO, despite working in crypto. Jentzsch was skeptical of ICOs, viewing many as unregulated securities offerings and potential scams. The team grew to 14 people, mostly developers, scaling operations across Europe. The business model: transaction fees on rental agreements executed via the platform. Jentzsch himself worked from Berlin, where a comfortable monthly household budget runs 2,000–3,000 euros, and he paid his team standard salaries in fiat currency—pragmatism over ideology. Users pay in euro-pegged tokens rather than volatile ether, recognizing that "crypto is not a very good currency yet," though it excels as a platform for programmable money and complex contractual logic.