# Data Field Types and Input Formats

When submitting contact data via the KlickTipp Listbuilding API, all values must match the field types and field keys configured in your KlickTipp account.

The KlickTipp API does **not** provide endpoints to retrieve field definitions or metadata.
Your integration must therefore ensure that values are sent in the correct format.

This document describes all supported field types and their expected input formats.

## General Rules

- Field keys must exactly match the keys configured in the KlickTipp account
- Values must conform to the expected field type
- Invalid formats will result in [validation errors](/guides/error-handling#business-and-validation-errors)
- Date and time fields must always be sent as Unix timestamps


## Supported Field Types

| Field type | Comment | Example |
|  --- | --- | --- |
| Line | String, single-line text | `Alex` |
| Paragraph | String, line breaks allowed | `Line 1 \n Line 2` |
| E-mail | Valid email string, must contain `@` | `alex.example@klicktipp.example` |
| Number | Integer, send as numeric value, not as string | `100` |
| Decimal number | Integer, send value multiplied by 100. The UI displays value divided by 100 with `.` (UI: `19.99`). | `1999` |
| URL | Absolute URL, must start with `http://` or `https://` | `https://www.klicktipp.example` |
| Date | Unix timestamp in seconds, do not send formatted date | `755222400` |
| Date & time | Unix timestamp in seconds, not milliseconds | `1715603400` |
| Time | Seconds since midnight (`0-86399`) | `52200` |


### Important Validation Notes

1. Use Unix timestamps in **seconds** only, for example `755222400`, not `755222400000`.
2. For numeric custom fields, send numeric values as numbers when possible, for example `100` instead of `"100"`.
3. Decimal number fields expect a scaled integer (factor 100), not a literal decimal string. Send `1999` to display `19.99` in the UI.
4. Phone values such as `+491701234567` are text values and should be treated as strings.


## Date and Time Fields

Although date and time values are displayed as formatted strings in the KlickTipp UI, the API **always expects Unix timestamps**.

This applies to the following field types.

- Time
- Date
- Date & time


Sending formatted date strings instead of timestamps will result in [field validation errors](/guides/error-handling#business-and-validation-errors).

## Common Validation Mistakes

- Sending formatted date strings instead of Unix timestamps
- Sending decimal values to integer number fields
- Using invalid URLs without protocol
- Sending text values to numeric fields
- Using incorrect or outdated field keys


If a value does not match the expected field type, the API will reject the request with a [field validation error](/guides/error-handling#business-and-validation-errors).

## Summary

- All values must match the configured field type in the KlickTipp account
- Date and time fields must always be sent as Unix timestamps
- Invalid formats result in field validation errors, not silent coercion
- Correct field mapping is the responsibility of the integration
- The API does not expose field metadata or field types


## Related Topics

- [Subscription Error Handling & Validation Errors](/guides/error-handling)
- [Listbuilding API Reference](/listbuilding-api)
- [Management API Reference](/management-api)