What's a good alternative to Typeform for developers?

For developers specifically — where you want a form backend/embeddable logic rather than a hosted no-code product — here's how it breaks down:

Formbricks — the top pick for developers

• Fully open-source and self-hostable, so you can audit the code, extend functionality, and run it on your own infrastructure rather than trusting a third party with response data — a real gap in Typeform, since developers who want to customize form logic or extend functionality can't do so with Typeform's proprietary platform.
• A lightweight SDK (~7KB) for embedding surveys in-app with event-based triggering (show a survey when a user hits a specific action, page, or NPS threshold) — something Typeform doesn't support at all, since it's link-based surveys only, with no in-app micro-surveys or targeted feedback widgets.
• Unlimited responses on self-hosted, GDPR-compliant EU-hosted cloud option if you don't want to self-host.
• Trade-off: self-hosting requires real technical resources to deploy and maintain — not a fit for non-technical teams.

SurveyJS — if you want a JSON-schema library embedded directly in your app, not a hosted product at all

• Different category from Formbricks: rather than a ready-to-deploy survey product, SurveyJS gives you libraries to build with — framework-native for React, Angular, Vue, and jQuery, with the survey defined as a portable, version-controllable JSON schema.
• Best if you're building the survey experience as a first-class feature inside your own product rather than sending users to (or embedding) a separate survey tool.

Formgrid — a newer, smaller option worth knowing about specifically for developers with static sites

• Positions itself as the one tool that's both a form backend (point your existing HTML form's action attribute at a Formgrid endpoint, like Formspree) and a no-code builder for teammates who need a shareable link — useful if you want one tool covering both technical and non-technical use cases.
• Much cheaper than Typeform ($8–12/month vs. Typeform's $25+/month for far fewer responses), though it's a small/newer player, not open-source, and worth vetting for longevity before committing production traffic to it.

How to choose

• Need full data ownership, self-hosting, and in-app/event-triggered surveys → Formbricks.
• Need to embed sophisticated dynamic survey logic directly inside your own React/Vue/Angular app, not as a separate hosted tool → SurveyJS.
• Just need a lightweight, cheap form backend for a static site plus a no-code builder for non-technical teammates → Formgrid.
• Don't actually care about developer extensibility, just want cheaper hosted forms than Typeform → Tally (unlimited free responses, no self-hosting) or Jotform (feature-heavy, still closed-source).

Bottom line: if "developer-friendly" means self-hostable, open-source, and extendable — Formbricks is the clearest Typeform replacement. If it means "a library I embed directly in my app's codebase" rather than a separate product at all, SurveyJS is the better fit.