Input Rules let you set extra requirements for what someone can enter in a field. They run when the form is submitted, on top of the field's built-in checks (the Required toggle and any type-specific checks like email format).
Find the Input Rules option in any field's settings panel in the form builder.
Writing a Rule
Type one or more rules into the Input Rules field, separated by pipes (|):
min:3|max:50
alpha_num|max:20
regex:/^[A-Z]{2}-\d{4}$/
If a rule isn't valid, the form builder will reject it when you save the field.
Length
Constrain the length of text or the size of a number.
| Rule | Description |
|---|---|
min:3 |
At least 3 characters (or numeric value ≥ 3) |
max:255 |
At most 255 characters (or numeric value ≤ 255) |
size:5 |
Exactly 5 characters |
between:5,20 |
Between 5 and 20 characters |
Numbers
Use these on Number fields, or on text fields where the value should look like a number.
| Rule | Description |
|---|---|
numeric |
Must be a number |
integer |
Must be a whole number (no decimals) |
decimal:2 |
Must have exactly 2 decimal places |
gt:0 |
Greater than 0 |
gte:1 |
Greater than or equal to 1 |
lt:1000 |
Less than 1000 |
lte:100 |
Less than or equal to 100 |
Letters & Patterns
Constrain which characters are allowed in a text value.
| Rule | Description |
|---|---|
alpha |
Letters only |
alpha_num |
Letters and numbers |
alpha_dash |
Letters, numbers, dashes, and underscores |
lowercase |
Must be lowercase |
uppercase |
Must be uppercase |
starts_with:DR- |
Must start with the given text |
ends_with:.pdf |
Must end with the given text |
regex:/^[A-Z]{2}\d{4}$/ |
Must match the given regular expression |
Format
Built-in checks for common formats.
| Rule | Description |
|---|---|
email |
A valid email address |
url |
A valid URL |
ip |
A valid IP address |
uuid |
A valid UUID |
Choice
Restrict input to a fixed set of values.
| Rule | Description |
|---|---|
in:foo,bar,baz |
Must be one of the listed values |
not_in:test,example |
Must not be one of the listed values |
Date
Use these on Date fields. Reference dates can be today, tomorrow, yesterday, or any date in YYYY-MM-DD format.
| Rule | Description |
|---|---|
date |
A valid date |
after:today |
After the given date |
after_or_equal:2026-01-01 |
On or after the given date |
before:2030-01-01 |
Before the given date |
before_or_equal:2026-12-31 |
On or before the given date |
Yes / No
Use these on toggle / yes-no inputs.
| Rule | Description |
|---|---|
boolean |
Must be a true/false value |
accepted |
Must be yes, on, 1, or true — handy for "I agree" style fields |
declined |
Must be no, off, 0, or false |
Tips
- Input Masks shape the value as it is typed; pair a mask with a
regex:rule when you need to enforce the format on submit. - Combine multiple rules with
|to apply them all (e.g.alpha_dash|min:4|max:20).
Related
- Input Masks — auto-format values as the user types
- Form Validation — overview of all validation options
- Field Types — built-in validation per field type