> This page location: Solutions > The back end with the rules built in.
> Full index for agents: https://www.semantius.com/llms.txt

# The back end with the rules built in.

> Business rules, roles and approval steps enforced in Postgres for every app, API and agent login, an API and an app that follow the model, and everything you self-host under MIT.

- **URL**: https://www.semantius.com/solutions/backend

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For builders and developers


Your agent shapes the model. The API, the app and the rules come from that one definition, and the rules are enforced in Postgres for every app, API and agent login, where you've defined them.

Everything you run yourself is MIT: the Postgres extension, the app, the sign-in server, the CLI and the agent skills. Pro cloud features aren't MIT.

For builders who want the speed of no-code and low-code tools, with the rules in the database.

## Day 30, not day 1

Any tool can build an app on day one. When the business changes, your agent changes the model, and the API and the app follow, with no frontend code to maintain.

**Not generated code, a model.** Rules, roles and steps are part of the data model, so every app, API and agent inherits them. Secure and extensible by definition.

Business rules are short JSONLogic expressions, stored and evaluated in PostgreSQL.

## The app

- **Screens come from the model,** not hand-coded per table: there's no boilerplate to write or maintain.
- **Self-hosted:** an MIT-licensed React app you can host on any static host or CDN.
- **In the cloud:** ready to use on desktop and mobile, in the browser.
- **Self-hosted, with your own branding:** theming, per-view overrides, chart plugins and config-driven menus.

## For builders

- **Several clients, one account:** one account manages several independent, self-contained data platforms, one per client.
- **Hand-over:** export a module and import it into the client's production or server, under MIT.
- **License:** Everything you run yourself in Semantius is MIT at any company size, while Directus, since v12, uses MSCL 1.0, the Monospace Sustainable Core License.
- **Self-hosting:** on Docker Compose or Dokploy.
- **The client's sign-in:** in the cloud, people sign in with their Google or Microsoft 365 account, with no Entra ID setup; self-hosted, the client's own Microsoft Entra ID or any identity provider with a JWKS endpoint.
- **Models as files:** export a module as JSON, review it in a pull request, and promote it from development to production.
- **Moving from another system:** export your data, and your agent imports it into the Semantius model. Semantius works on its own model; it doesn't attach to existing tables.

[Read the specification](https://www.semantius.com/solutions/agent-guardrails.md#specification)

- Customizing the app TBD No docs page exists yet.
- Module export TBD No docs page exists yet.
- [Self-hosting](https://www.semantius.com/docs/self-hosted.md)

[Start free](https://app.semantius.com/auth/sign-up) [Self-host with Dokploy](https://www.semantius.com/docs/self-hosted/dokploy.md) [GitHub](https://github.com/Semantius)

- [See how guardrails work](https://www.semantius.com/solutions/agent-guardrails.md)
- [See business apps](https://www.semantius.com/solutions/business-apps.md)
- [See pricing](https://www.semantius.com/pricing.md)

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- [Full index for agents](https://www.semantius.com/llms.txt)