# Collection field types Every field type a collection version takes, what each stores, its settings and the errors a write can get. Each field on a [collection version](/collections/overview) has a `type`. The type decides what a record stores under the field's `slug`, which settings the field takes, and what a write is refused for. ```json title="A version's fields" { "fields": [ { "slug": "name", "title": "Name", "type": "text", "required": true, "max": 80 }, { "slug": "size", "title": "Size", "type": "select", "options": [ { "value": "s", "label": "Small" }, { "value": "m", "label": "Medium" } ] }, { "slug": "seats", "title": "Seats", "type": "integer", "min": 1, "max": 500 }, { "slug": "budget", "title": "Budget", "type": "money", "currency": "usd" }, { "slug": "office", "title": "Office", "type": "location" } ] } ``` A record written against that version: ```json title="Record data" { "name": "Acme", "size": "m", "seats": 40, "budget": { "amount": 250000, "currency": "usd" }, "office": { "address": { "city": "Berlin", "country": "DE" } } } ``` > **Note:** Add fields in the BuildBase console under **Collections**, on a draft version. The console shows each type by its label (the second column below); the API takes the stored name. ## The types | `type` | Console label | A record stores | Settings | | -------------- | --------------- | ------------------------------------------------- | ----------------------------------- | | `text` | Text | A string | `min`, `max`, `pattern` | | `rich-text` | Rich text | A string of formatted text | `min`, `max` | | `email` | Email | A string in email form | `min`, `max`, `pattern` | | `link` | Link | An `http` or `https` URL | `min`, `max`, `pattern` | | `color` | Color | A string | `min`, `max`, `pattern` | | `number` | Number | A number, decimals allowed | `min`, `max` | | `integer` | Whole number | A whole number | `min`, `max` | | `bool` | Checkbox | `true` or `false` | None | | `date` | Date | A date string | None | | `select` | Choice | One option's `value` | `options` | | `multi-select` | Multiple choice | A list of option values | `options`, `min`, `max` | | `money` | Money | `{ amount, currency }`, the amount in minor units | `currency` (required), `min`, `max` | | `location` | Location | `{ address?, point? }` | None | | `file` | File | An asset reference, or a list of them | `maxMb`, `maxFiles` | Note the name `bool`, not `boolean`. A type the version does not know is refused when the version is saved. ## What every field has | Property | Type | Required | Description | | -------------- | --------- | -------- | ------------------------------------------------------------------------------- | | `slug` | `string` | Yes | The key the value is stored under. Starts with a letter; `a-z`, `0-9`, `-`, `_` | | `title` | `string` | Yes | The field's name, shown on forms and in the console | | `type` | `string` | Yes | One of the types above | | `helpText` | `string` | No | A hint shown under the field | | `required` | `boolean` | No | A write without a value is refused. Default `false` | | `defaultValue` | the type | No | Must itself be a valid value for the field | The console offers a default value for text, rich text, number, checkbox, date, color, link and email fields. A choice, a whole number, money, a location and a file start empty. ## Limits The platform's ceilings, whatever a field says: | Limit | Value | | ------------------------------------- | -------------------- | | Fields in one version | 100 | | `slug` length | 64 | | `title` length | 120 | | `helpText` length | 500 | | Options on a choice field | 200 | | One option's `value` or `label` | 120 | | `pattern` length | 200 | | `max` on a field that has a `pattern` | 1,000 | | One text value | 1,000,000 characters | | A location's address line | 200 characters | ## Text, email, link and color `min` and `max` count characters. An `email` value must look like an email address, and a `link` value must start with `http://` or `https://`. `pattern` is a regular expression the **whole** value must match, on `text`, `email`, `link` and `color` fields. Two rules keep a pattern safe to run on what strangers send: - A field with a `pattern` sets a `max` of 1,000 or less. - A pattern that could take very long to test is refused when the version is saved: no backreference (`\1`), and no repeated group that itself repeats or holds a choice (`(a+)+`, `(a|aa)*`). `[A-Z]{3}-\d+`, `(foo|bar)` and `(ab)+` are fine. ```json title="A postcode field" { "slug": "postcode", "title": "Postcode", "type": "text", "max": 10, "pattern": "[0-9]{5}" } ``` ## Number and whole number A string that reads as a number is stored as one: `"5"` is stored as `5`. `integer` refuses anything that is not a whole number. `min` and `max` bound the value, and may be negative. ## Checkbox and date A `bool` field takes `true` or `false`, or the strings `"true"` and `"false"`, and stores the boolean. A `date` field takes a date string (`"2026-11-03"` or a full ISO timestamp) and stores it as sent; a bare number is refused. ## Choice and multiple choice Both need `options`: 1 to 200 of them, each with a distinct `value` and a `label`. The record stores the `value`; the label is for people. A `multi-select` value is a list of distinct option values. Its `min` and `max` count how many are picked. ```json title="A multiple-choice field and its value" { "slug": "tags", "title": "Tags", "type": "multi-select", "max": 3, "options": [ { "value": "new", "label": "New" }, { "value": "sale", "label": "On sale" } ] } ``` ```json title="Record data" { "tags": ["new", "sale"] } ``` ## Money A money value is `{ "amount": 1999, "currency": "usd" }`: the amount in the currency's minor units (cents for US dollars, whole yen for yen), never negative, and a lower case ISO 4217 code for a currency in circulation. A collection's money field **must** name its `currency`; saving a version with a money field and no currency is refused. A value in any other currency is refused, so every record of the field is in the same currency. `min` and `max` bound the amount, in minor units. ## Location A location is an address, a map point, or both: ```json title="Record data" { "office": { "address": { "line1": "Unter den Linden 1", "city": "Berlin", "postalCode": "10117", "country": "DE" }, "point": { "lat": 52.517, "lng": 13.389 } } } ``` The address takes any of `line1`, `line2`, `city`, `state`, `postalCode` and `country`, each a string of up to 200 characters. `country` is an ISO 3166 two-letter code and is stored upper case. `point` takes exactly `lat` (-90 to 90) and `lng` (-180 to 180). Any other key is refused. ## File A `file` field holds images as your [assets](/assets/overview), never the bytes. Its settings, what a record stores and how to write one are on [the overview](/collections/overview#file-fields). ## When a write is refused A record written through the API is checked against its version's fields. The first problem answers `400` with the field and what is wrong: ```json title="400 response" { "error": true, "message": "Seats must be at most 500" } ``` A [public form](/forms/overview) submission answers every problem at once: ```json title="400 response" { "success": false, "message": "Validation failed", "errors": ["Seats must be at most 500", "Budget must be in USD"] } ``` Keys that are not fields of the version are dropped, not refused. An empty value (`""`, `null` or `[]`) on an edit clears the field. ## Check values in your own app The SDK runs the same checks, so a form can say what is wrong before it sends. The server checks again, and its answer counts. ```typescript title="lib/check-order.ts" import { checkFieldValues, type FieldDefinition } from '@buildbase/sdk'; export function checkOrder( fields: FieldDefinition[], data: Record ) { const { values, errors } = checkFieldValues(fields, data); // errors: [{ slug: 'seats', code: 'too_large', message: '...' }] return errors.length ? { errors } : { values }; } ``` Each error has a `code` your app can put in its own words: | `code` | Meaning | | ------------------ | ------------------------------------------------------ | | `required` | A required field has no value | | `invalid_type` | Not a value of the field's type | | `too_short` | Fewer characters than `min` | | `too_long` | More characters than `max` | | `too_small` | Below `min` | | `too_large` | Above `max` | | `too_few` | Fewer choices than `min` | | `too_many` | More choices than `max`, or more files than `maxFiles` | | `pattern_mismatch` | Does not match the field's `pattern` | | `not_an_option` | Not one of the field's options | | `duplicate` | The same choice or file twice | | `wrong_currency` | Money in another currency than the field's | ## Next Steps - [Collections overview](/collections/overview) - versions, file fields and endpoints. - [Records API](/collections/records-api) - read and delete stored records. - [Forms](/forms/overview) - collect records from a public endpoint.