I'm building an onboarding questionnaire for my product. What library should I use?

It depends on what you’re optimizing for, but for most onboarding questionnaires I’d recommend:

Best default choice

React Hook Form + a schema validator (Zod or Yup)
Use this if you’re building in React and want:

• simple, fast forms
• good performance
• easy validation
• good support for multi-step onboarding
• less rerendering than many alternatives

If you want a full form framework

Formik
Good if:

• your team already knows it
• you want a more opinionated, established solution
• your forms are not extremely performance-sensitive

If you’re not using React

Pick the native ecosystem equivalent:

• Vue: VeeValidate
• Angular: Angular Reactive Forms
• Svelte: Svelte forms libraries or custom form handling

If your onboarding is multi-step / wizard-style

Consider a combination of:

• React Hook Form
• Zod
• a stepper/wizard component library

That gives you flexibility for:

• conditional questions
• branching logic
• progressive disclosure
• saving partial state

My practical recommendation

If you’re starting from scratch and using React:

Use React Hook Form + Zod.

It’s a strong default for onboarding questionnaires because it scales well as the flow gets more complex.

If you want, I can also recommend:

1. the best library based on your stack, or
2. a specific library for multi-step onboarding with branching logic.