FormEngine Core vs Designer: Which Do You Need?

TL;DR: FormEngine Core is a free, MIT-licensed React library for rendering JSON-driven forms. FormEngine Designer is a commercial embeddable visual form builder — a drag-and-drop editor your end-users or team members use to create and edit forms without writing JSON. You need Core regardless; you only need Designer if someone in your workflow needs to build or modify forms through a UI. Last reviewed: April 2026.

At a glance

	FormEngine Core	FormEngine Designer
What it is	React form renderer	Embeddable visual form editor
Who uses it	Developers	Developers + end-users / business users
License	MIT (free)	Commercial (paid)
Source available	Yes	Yes (source-available)
Renders forms	Yes	Uses Core to render
Builds/edits forms	JSON only	Drag-and-drop UI
Requires backend	No	No
Embeddable in your app	Yes	Yes
Custom component palette	Yes (code)	Yes (visual)
Visual conditional logic	No	Yes
Output format	—	FormEngine JSON (same schema Core reads)

FormEngine Core

Core is the rendering engine. It takes a JSON schema and renders a form using whichever React component library you configure — Material UI, Mantine, RSuite, or your own.

import { FormViewer } from '@react-form-builder/core'
import { view } from '@react-form-builder/components-material-ui'

<FormViewer
  view={view}
  form={JSON.stringify(schema)}
  onActionEventAsync={async (event) => {
    if (event.name === 'submit') await handleSubmit(event.args.formData)
  }}
/>

Core handles:

Schema parsing and component resolution
Form state management
Per-field validation (built-in and custom)
Conditional rendering via renderWhen
Computed properties
Action sequences
Multi-step forms via the Wizard component
Repeating sections via Repeater

Who needs Core: every team using FormEngine. It’s the foundation everything else builds on. License: MIT. Free for any use, including commercial. No attribution required beyond the license file.

FormEngine Designer

Designer is an embeddable visual form builder — a React component you drop into your app that gives users a drag-and-drop interface for building forms. The output is the same JSON schema Core reads.

import { FormBuilder } from '@react-form-builder/designer'

<FormBuilder
  view={view}
  onSave={async (schema) => {
    await saveToDatabase(schema) // your storage
  }}
  initialForm={existingSchema} // optional
/>

Designer handles:

Component palette with drag-and-drop
Visual prop editing (labels, placeholders, options)
Visual validation rule configuration
Visual renderWhen condition builder
Visual action editor
Form preview in the editor

Who needs Designer:

SaaS products where customers build their own forms
Internal tools where business analysts or ops teams configure forms without developer help
Any workflow where form structure needs to change faster than the deploy cycle

Who doesn’t need Designer:

Teams where forms are only modified by developers (Core + JSON is enough)
Projects with a fixed set of forms that rarely change

License: Commercial. Per-deployment pricing — one license covers an entire application deployment, regardless of how many end-users use the Designer. See pricing page.

How they work together

Designer writes; Core reads. The typical integration:

FormBuilder (Designer)  →  save JSON to DB  →  FormViewer (Core) renders it

An admin or customer uses Designer to create a form
Designer calls your onSave callback with the JSON schema
You store the schema in your database
When a user fills out the form, FormViewer loads the schema and renders it

Both components use the same view configuration — so the component palette in Designer matches exactly what Core renders. There’s no format conversion.

Licensing FAQ

Do I need a Designer license to use Core?

No. Core is MIT. You can use it in any project, commercially or otherwise, without a Designer license.

What counts as a “deployment” for Designer licensing?

One production deployment of the Designer component. A SaaS product with 10,000 customers using a Designer-powered form builder is one deployment, not 10,000.

Can I use Designer in development for free?

Designer has a development/evaluation mode. Check the pricing page for the current terms — policies may have updated since this page was last reviewed.

Do I need a license for staging environments?

Check the current licensing terms at the pricing page. Staging policies vary.

What happens if I use Designer without a license in production?

Designer displays a licensing notice. It continues to function technically, but the notice is visible to your users.

Is the Designer source code available?

Yes, under a commercial source-available license — you can read and modify the source, but redistribution and sublicensing are restricted. This is different from MIT.

Start paths

I need to render JSON forms in React: → Install Core → Rendering forms I need to let users build forms visually: → Designer installation → Designer usage → Pricing I need to embed a form builder in my SaaS product: → SaaS form builder use case → Designer customization I want to understand the architecture: → FormEngine architecture

FormEngine on GitHub · npm · Pricing

​At a glance

​FormEngine Core

​FormEngine Designer

​How they work together

​Licensing FAQ

​Do I need a Designer license to use Core?

​What counts as a “deployment” for Designer licensing?

​Can I use Designer in development for free?

​Do I need a license for staging environments?

​What happens if I use Designer without a license in production?

​Is the Designer source code available?

​Start paths