Fields
Field behaviour, calculations, option sources, and custom field authoring.
Bringing your Craft field into Formie (Custom Field adapters)
Formie's Custom Field field type lets authors pick from supported Craft fields without you registering a separate Formie field for every plugin. Each supported option is an adapter — explicit Formie code that handles front-end rendering, validation, storage, exports, integrations, and GraphQL.
Calculations field in detail
This guide walks through Calculations syntax, field references, built-in functions, and practical examples. Use it alongside the Calculations field reference when you are building pricing, scoring, or conditional output on a form.
Creating a custom option source provider
Custom option source providers expose server-resolved { label, value } rows for Dropdown, Radio, Checkboxes, and Recipients fields. They appear in the form builder as Custom Provider when they declare support for the current field usage.
Creating a Formie field type from scratch
In this guide we build a URL field from scratch — similar to Single-line Text, but with URL validation and optional front-end behaviour. By the end you will have a field that appears in the form builder palette, renders on the front end, validates submissions, and supports Theme Config.
Dynamic option sources in practice
Dropdown, Radio, and Checkboxes fields can pull their options from several source types — not just a manually maintained table. This walkthrough shows when to use each option source and how they behave at render and submit time.
How to modify Element field queries to change what elements can be chosen
Element fields — Entries, Categories, Users, Tags, Products, and Variants — all work the same way underneath: Formie builds an element query from the field settings, then renders that list as a dropdown, radio buttons, checkboxes, or multi-select. That is much more efficient than copying hundreds of options into a static Dropdown field.
Payment field with Stripe — full flow
This walkthrough connects Stripe to a Formie form end to end: integration setup, Payment field configuration, form behaviour, and optional subscription features.
Surveys, polls and quizzes end-to-end
Formie separates questionnaire use cases into two field types: Survey for collecting and aggregating responses, and Quiz for scored assessments with pass/fail logic. Simple polls — single-question votes — are built with Survey fields using Radio or Dropdown presentation.
Write your own parsing logic for the Calculations field
The Calculations field evaluates a formula from other field values and shows the result in a read-only input. Formie uses a JavaScript implementation of Symfony Expression Syntax for front-end evaluation. When built-in formatting is not enough — currency display, rounding rules, capping input values before they enter the formula — you can hook into evaluation events and adjust the formula, variables, or result.