History
Origin
ZITADEL was built by CAOS AG, a company founded in 2019 in St. Gallen, Switzerland, by Florian Forster (CEO), Fabienne Bühler, and Maximilian Panne, who came from identity and infrastructure backgrounds (About ZITADEL). The GitHub repository was created on 2020-03-16 (GitHub repo metadata).
The stated goal was to combine the developer experience of Auth0 with the self-hosting control of Keycloak, and to make multi-tenancy a first-class design property rather than something bolted on later. The team chose Go and an event-sourced architecture to deliver that (About ZITADEL). Being based in Switzerland is also a deliberate data-sovereignty pitch toward finance, healthcare, and government workloads.
Timeline
| Year | Milestone |
|---|---|
| 2019 | CAOS AG founded in St. Gallen, Switzerland (About) |
| 2020 | GitHub repository created on 2020-03-16 (repo metadata) |
| 2022 | Seed round, then a $9M Series A led by Nexus Venture Partners with Floodgate participating; over 150 companies and 10k+ stars claimed at the time (Series A) |
| 2025 | v3 (2025-03-31): license changed from Apache-2.0 to AGPL-3.0, and CockroachDB support dropped in favor of PostgreSQL only (v3 announcement) |
| 2026 | Active release stream on main; tag v4.15.2 shipped 2026-06-17 (repo) |
How it evolved
The defining shift was v3 in March 2025, which made two large changes at once. First, the project relicensed from Apache-2.0 to AGPL-3.0-only to protect against unpaid commercial reuse, while keeping the proto/ definitions and SDKs under permissive licenses so that generated gRPC client code does not inherit copyleft (Moving to AGPL, LICENSING.md). Second, CockroachDB support was removed and PostgreSQL became the only supported database; existing v2.x CockroachDB deployments were kept on maintenance-only support until 2025-09-30 (Key Changes in Version 3).
The total funding raised across rounds is about $15.5M (Series A). The codebase also shows an in-progress next-generation backend under backend/v3/, which main.go already imports for instrumentation, signaling an ongoing internal restructuring rather than a finished rewrite.
Where it stands now
ZITADEL ships frequently, with point releases on the v4 line in mid-2026 and a v5.0.0-base version tag present in the repository. Development is company-led by what is now ZITADEL (formerly CAOS AG), and the project runs a dual-license, commercially self-funded model rather than seeking neutral foundation governance. The maintainers have explicitly contrasted this with Keycloak's 2023 entry into CNCF incubation, framing self-sustaining open source as their chosen path (Open Source in the AI Era).