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

# Custom fields

> Add your own fields to the standard Bonx entities.

Your business tracks information a standard ERP does not plan for: a revision index
on an article, a customer file number on an order, a temperature recorded on a lot.
Rather than squeezing it into a comment field, you add a **custom field** to the
entity concerned.

A custom field behaves like a standard one: it appears on the record, in tables, in
filters and groupings, in the change history, and it can be read and written through
the **API** with the same conventions as everything else.

## Available types

| Type | Use |
| - | - |
| **Text** | one line, for a reference or a code |
| **Long text** | several lines, for a structured note |
| **Number** | quantity, measurement, coefficient |
| **Boolean** | a checkbox |
| **Date** | a date on its own |
| **Date and time** | a timestamp |
| **Choice list** | one value from a list you define |

## Good to know

* Custom fields on standard entities carry a **prefix** in the API, so they can
  never collide with a future standard field.
* A **default value** can be computed at creation, from other fields of the record.
* A field can be **removed**; the values entered go with it, so the operation is not
  a trivial one.

<Note>
  If the information you want to track has a life of its own, with several records and its own fields, what you need is
  not a field but a [custom table](/en/customization/custom-tables).
</Note>


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