> ## Documentation Index
> Fetch the complete documentation index at: https://api-doc.fidly.be/llms.txt
> Use this file to discover all available pages before exploring further.

# Sandbox

> Test your integration against fixtures, with the exact validations of live.

Each API client is either **live** or **sandbox**. A sandbox client has no access
to production data: it lets you integrate your software in an isolated environment.
Ask for a sandbox client in the Fidly interface to develop and test.

## What a sandbox client sees

* **Reads** return static fixtures: demo documents, relations, journals, bank
  accounts and delivery locations. No real company data is ever involved.
* **Writes** (`POST`, `PATCH`, `DELETE`) run **exactly the same validations and
  return the same error codes as live**, but your data will not be modified.

## Consequences to code against

* The `id` returned by a sandbox creation is generated on the fly and **not
  resolvable**: a later `GET` on it returns `404`.
* A sandbox `PATCH` returns the modified object, but fixtures are shared and frozen:
  the next `GET` returns the object unchanged.

<Info>
  The sandbox is for validating your calls and does not store your changes.
</Info>

## Document creation and update in sandbox

Creating or updating a document goes further than plain validation: amounts, VAT,
the document number (drawn from the fixture journal's sequence) and the structured
payment reference are really computed. The journal is checked as in live: the
document must be booked in a journal whose category matches its type, resolved
among the fixture journals. `issue_date` is bounded exactly as in live: within the
numbering window, never in the future, never before the last document of the
fixture sequence.

Fixture companies carry payment terms of their own, inherited as in live when the
body gives none (a contact never has any).

One deliberate difference with live: **self-billing is considered enabled** —
`purchase_invoice` and `purchase_credit_note` are creatable in sandbox even though
live requires the company setting.

The payment exemption also holds in sandbox: a `PATCH` carrying only `paid_amount`
passes on a fixture that is already sent or exported, as it would in live.