Wilco Kruijer

Wilco Kruijer
Occupation	Entrepreneur, software engineer
Known for	Co-founder and CEO of ReJot

Wilco Kruijer is a Dutch entrepreneur and software engineer who is the co-founder and CEO of ReJot, a developer tools company that builds infrastructure for data synchronization between backend services. ReJot was part of the Y Combinator Winter 2025 batch.

Career

Kruijer co-founded ReJot alongside Jan Schutte, who serves as the company's chief technology officer. The company is based in Amsterdam, Netherlands, with a registered presence in Dover, United States.

ReJot initially developed a synchronization engine designed to reduce the complexity of data sharing between backend services within enterprises. The company's core technology is based on database replication rather than traditional event streaming approaches such as Apache Kafka. By leveraging a database's write-ahead log as an asynchronous communication channel, ReJot enables data to flow between services without the operational overhead of message brokers, partitions, or outbox patterns. Teams define what data their backend publishes and requires, and the system keeps everything reactively up to date. The platform works on top of existing infrastructure such as PostgreSQL.

The company subsequently expanded its product offering with Fragno, an open-source framework that allows API companies to package backend endpoints, data storage patterns, and frontend utilities into reusable building blocks. Rather than providing low-level SDKs and documentation, API providers using Fragno can ship full drop-in integrations that customers configure rather than code from scratch, allowing for faster launches and more consistent implementations across customers.

In February 2025, ReJot raised a $500,000 seed round with participation from Y Combinator, Initialized Capital, AngelList, and angel investor Akhil Paul.

Kruijer has written about data engineering challenges in enterprise software. In January 2025, he published an essay titled "The Burdens of Data" on the ReJot blog, exploring approaches to reducing the complexity that software engineers face when working with data in larger organizations.

ReJot operates in the developer tools space, spanning categories including API infrastructure, databases, and general developer infrastructure. The company's open-source tooling is available via npm and GitHub.