ReJot

Active

We turn complex API integrations into drop‑in full‑stack libraries

Winter 2025Founded 20242 peopleAmsterdam, NH, Netherlands

rejot.dev ↗LinkedIn ↗X ↗GitHub ↗See on the Idea Map B2B momentum

About

ReJot is building Fragno to let API companies go from simply exposing an API to offering drop-in integrations that work out of the box. Fragno is an open‑source framework for packaging backend endpoints, data storage patterns, and frontend utilities into reusable building blocks. API providers ship full integrations, not just low‑level SDKs and docs. Customers configure rather than write code, so integrations are both much faster to launch and far more consistent across customers.

From their website

as of Jun 7, 2026rejot.dev ↗

Open-Source/Developer Tool

ReJot builds software that simplifies and accelerates complex API integrations by providing drop-in full-stack libraries. The project focuses on exploring distributed systems, databases, and programming languages, aiming to enable easier integration work through open-source tooling.

ReJot provides open-source builders of better software, delivering drop-in full-stack libraries designed to simplify API integration. The product emphasizes working with distributed systems, databases, and programming languages, offering tooling and libraries intended to be dropped into existing projects to streamline integration and backend workflows.

Who it’s for: Developers and engineering teams building applications that rely on complex API integrations, distributed systems, and database-backed services.

Features

drop-in full-stack libraries for API integrations
support for distributed systems with database integration
open-source tooling for better software construction
focus on programming language compatibility
inferred tooling for inbound/outbound integration workflows
educational content and project feed showcasing updates

backed by Y Combinator; active open-source project with project feed and updates

Founders · 2

Wilco KruijerFounder

CEO & Co-founder at ReJot, previously worked on a distributed financial platform at Adyen. Interested in the relation between distributed data and software maintainability.

LinkedIn ↗X ↗

Jan SchutteCTO / Co-Founder

CTO & Co-founder at ReJot, former Data Platform Engineer at Adyen, interested in distributed systems and database technologies. Current product is https://fragno.dev/

LinkedIn ↗X ↗

Launch

Launched on Y Combinator · Feb 2025

View launch post ↗

Sync engine to share data across engineering teams in enterprises

ReJot launches an open-source Limited Access Preview of a sync engine that enables sharing data between back-end services without APIs or event streaming. It targets large enterprises, allowing SQL-based querying across databases, controlled data-sharing primitives, and a data catalog to map and understand available data for cross-team integration.