best open source form builder

Here's the current landscape of the best open-source form builders, organized by use case:

Best general-purpose, no-code pick

• OpnForm — a clean, no-code form builder (PHP/Laravel backend, Vue frontend) that feels like the polished hosted tools but runs entirely on your own server. Open source (AGPLv3 core), unlimited forms and submissions on the free tier, with webhooks, API access, and custom code integration for downstream workflows. Ships docker-compose files, making self-hosting essentially copy-paste. The most consistently recommended general-purpose open-source pick across current comparisons.

Best for serious surveys and in-app feedback

• Formbricks — a privacy-first, open-source experience management platform combining link surveys (Typeform-style), in-app micro-surveys embedded directly in your product, and pop-up surveys triggered by user behavior. Dockerized, one-click self-hosting, a full open API, AGPLv3-licensed code you can inspect and extend. One of the fastest-growing open-source survey platforms currently. Best when you need behavior-triggered, contextual feedback rather than just static forms.

Best conversational/Typeform-style experience

• HeyForm — brings Typeform's one-question-at-a-time interaction to a fully open-source package. Self-hostable via Docker under AGPLv3, with an AI copilot, smart logic (conditional branching, URL redirections), and full visual theme customization with CSS access.
• Typebot — wins for conversational, chatbot-like flows specifically; self-hosts with no response caps.

Best embeddable library (native inside your own codebase)

• SurveyJS — a JSON-schema-driven library, not a standalone product — embed directly in React, Angular, Vue, or plain JS. The rendering engine is free (MIT-licensed, no usage caps); the visual drag-and-drop builder is a separate commercial add-on. Best when the form needs to render natively inside your own app.
• Form.io — open-source core, JSON-schema-driven with automatic REST API generation, permissions, and workflow logic — the right pick when the form needs to double as application infrastructure.
• Kinto — open-source, React-based form builder; flexible but the hardest of the group to get started with since it requires standing up a Kinto instance and coding knowledge.

Best for research-grade, multilingual surveys

• LimeSurvey — mature (20+ years active development), Community Edition free and self-hosted via Docker, 80+ language support, 30+ question types, advanced branching, GDPR compliance tooling, and API access. The gold standard for long, statistically rigorous, multilingual questionnaires.

Best for no-code database with attached forms

• Baserow — a no-code database first, with a Form view attached; less styling/logic depth than a dedicated form builder, but strong if you want the form to feed directly into a structured, queryable database you also control.

Best for internal-tool-style forms with workflow logic

• Budibase — a form builder bundled with a full low-code platform (database, automation workflows, authentication). Build forms from scratch or auto-generate them from a data schema; used by 300,000+ teams for internal operations.

Best for developer-first API/SDK access

• Formizee — built explicitly by developers for developers: full API access, self-hosting as open source, SDKs across multiple languages, team permissions, and GDPR compliance.

The universal trade-off None of these are static sites you can drop on a CDN — every one needs a real server with a database attached, and most need SMTP for email notifications. The payoff is no response caps, no per-seat pricing, no surprise bills, and full ownership of your data.

How to choose

• Want the closest feel to a polished hosted tool, general-purpose forms → OpnForm.
• Need behavior-triggered, in-app surveys, not just static forms → Formbricks.
• Want Typeform's conversational UX, fully open source → HeyForm or Typebot.
• Building the form natively inside your own app's codebase → SurveyJS or Form.io.
• Long, research-grade, multilingual questionnaires → LimeSurvey.
• Form is really a database or internal tool → Baserow or Budibase.

Bottom line: OpnForm is the most consistently recommended general-purpose open-source form builder, Formbricks is the strongest pick specifically for survey-grade logic and in-app feedback, and SurveyJS is the right choice if you want the form embedded natively inside your own codebase rather than deployed as a separate self-hosted product.