---
title: "Concepts"
description: "The concepts pages cover schema as code, the apply path, versioning, change approval, caching, tenant isolation, jobs, and the sandbox."
---

> Documentation Index
> Fetch the complete documentation index at: https://docs.tryatlantis.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Concepts

- [Schema as code](/concepts/schema-as-code/). The `.atl` files in git are
  authoritative; the database derives from them.
- [The apply path](/concepts/how-atlantis-runs-your-schema/). The checkpoint, the
  apply, hot reload, migration ownership, and the boundaries.
- [The typed query surface](/concepts/the-typed-query-surface/). What the generated
  per-entity methods can express.
- [The generated client](/concepts/the-generated-client/). Committed code, stable
  proto numbers, `generate --check`.
- [Schema versioning](/concepts/schema-versioning/). The append-only version
  registry: history, blame, staleness.
- [Change approval](/concepts/change-approval/). Classes, tiers, rehearsals,
  protections, freezes, overrides.
- [The console](/concepts/the-console/). What the browser view shows, and what
  deciding requires.
- [Custom queries and procedures](/concepts/custom-queries-and-procedures/). SQL
  beyond the typed surface.
- [Caching and invalidation](/concepts/caching-and-invalidation/). The two caches
  and the transactional outbox.
- [Tenant isolation](/concepts/tenant-isolation/). What `partition by` enforces,
  what it trusts, and where it stops.
- [Jobs and workflows](/concepts/jobs-and-workflows/). Typed background work and
  multi-step orchestration.
- [Ephemeral data](/concepts/ephemeral-data/). Typed, expiring stores with no
  table behind them.
- [The sandbox](/concepts/sandbox/). Disposable test databases holding schema
  only, never production data.

Source: https://docs.tryatlantis.dev/concepts/index.mdx