# Backups

URL: /code/platform/backups · Id: `capability:backups`

> Backups keep point-in-time copies of every namespace, so any past state reads back and any Change reverts.

Backups keep every past state of a namespace readable and every [Change](/business/nouns/change) revertible. Nothing in [db.sb](/code/platform/db-sb) is ever deleted, so a backup is history you can query.

## Contract
A delete is a marker that hides a [Thing](/business/nouns/thing) from reads and can itself be reversed. Definitions change only through Changes, which resolve to immutable [Versions](/business/nouns/version). Facts keep every revision.

| To | Do |
| --- | --- |
| Read a Thing as it was | `GET api.sb/{ns}/{collection}/{id}@2026-10-01T00:00Z`, or `at` on any get |
| List a Thing's Versions | `GET api.sb/{ns}/{collection}/{id}/versions` |
| Undo one Change | [Revert](/business/nouns/change/revert) it: a new Change with a superseding [Decision](/business/nouns/decision) |
| Undo many Changes | Revert by query, such as every Change one [Agent](/business/nouns/agent) merged on one day |
| Restore a namespace | One Change returns every record to a point in time |
| Survive a lost region | An independent archive copy of each namespace, kept in a second region inside its [residency](/code/platform/residency) (`us` or `eu`) |

Undo never un-moves money or un-sends a [Message](/business/nouns/message). Those take a reversing [Action](/business/nouns/action): a [refund](/business/nouns/order/refund) or a correction. Every revert names who made it and why.

## Verbs
| Verb | Object | Event |
| --- | --- | --- |
| [Change.revert](/business/nouns/change/revert) | [Change](/business/nouns/change) | [`Change.reverted`](/business/events/Change.reverted) |

## Interfaces
- [API](/code/api/reference)
- [SDK](/code/sdk/reference)
- [CLI](/code/cli/reference)
- [MCP](/code/mcp/reference)

## Example
`ledgerly.io`, a bookkeeping [Service](/business/nouns/service), merges a Change that doubles its monthly [Price](/business/nouns/price) by mistake. An Agent on its [Finance Team](/agents/finance) reverts the Change within the hour, and each overcharged [Customer](/business/nouns/customer) gets a refund as its own Action.