About Slicekit
A SaaS foundation you would have built anyway
Every new SaaS starts with weeks of the same plumbing: authentication, a typed client, background jobs, logging, dashboards, CI. Slicekit is that plumbing, assembled, wired together and tested, so the first thing you write is your product.
Design principles
Every decision in Slicekit follows a small set of principles. They are the reason the architecture looks the way it does and the reason you can hand it to a new engineer on day one.
One architecture, both sides
The API and the SPA follow the same vertical-slice shape. Learn one feature and you can navigate every feature, on either side of the wire.
Batteries included, not bolted on
Auth, audit, messaging, storage and observability are first-class parts of the template, not afterthoughts you wire up under deadline pressure.
Readable over clever
Explicit handlers, named events and obvious folders. The code is written to be read by the next engineer, or the next agent, six months from now.
Yours to own
Buy once and the code is yours under a commercial license: standard tooling, no proprietary runtime. Rename it, rip parts out, deploy anywhere. There is no platform to depend on.
What's in the box
A modern, mainstream stack with no exotic dependencies, chosen so the knowledge transfers to your other projects, and so hiring against it is easy.
- API
- .NET 10 · Minimal API · Wolverine CQRS · EF Core · PostgreSQL
- Frontend
- Vite · React 19 · TypeScript · TanStack Router & Query · shadcn/ui · Tailwind v4
- Messaging & storage
- RabbitMQ · Redis · SeaweedFS (S3) · transactional outbox
- Billing
- Stripe subscriptions · Checkout & Customer Portal · webhooks · feature-key entitlements
- Observability
- OpenTelemetry · Loki · Tempo · Prometheus · Grafana · Alertmanager
- Tooling
- Docker Compose · GitHub Actions · Testcontainers · architecture tests
Gerwin Kuijntjes
Certified Software Engineer
- Engineer-architected
- Human-reviewed
- Tested & typed
Why I built Slicekit
I'm Gerwin, a certified software engineer. On project after project, I rebuilt authentication, an audited admin, observability and the typed client between the API and UI. EU projects also needed account data export, deletion and consent records. Subscription billing with Stripe was another part I kept rebuilding.
Slicekit packages that foundation so you can start with your product's features and change the defaults as needed.
Architecture tests check boundaries, and integration tests use a real database. I review the code and take responsibility for the design.
What you're buying
Slicekit is a one-time purchase, not a subscription. You pay once, get the full source under a commercial license, and own it. There is no hosted service to lock you in and no per-seat tax on the product you build on top. Clone the private repo, delete what you do not need, and keep the parts that save you weeks. Lifetime updates are included.