\n\nThe framework-agnostic core of [Fillo](https://fillo.so) — forms that render **inside your own product**, with your UI, no iframe.\n\nThis package holds the shared foundation: the form schema, validation, the conditional-logic engine, response prefill/piping, and a JS client for provider-aware browser-direct uploads, with resume support where the storage provider offers it. It has **zero framework dependencies**.\n\nMost apps don't install this directly — you install a renderer (**[@usefillo/react](https://www.npmjs.com/package/@usefillo/react)** or **[@usefillo/dom](https://www.npmjs.com/package/@usefillo/dom)**), which re-exports everything here you need for embedding. Reach for `@usefillo/core` when you're building your own renderer or working with forms on the server.\n\n```sh\nnpm i @usefillo/core\n```\n\n```ts\nimport { createClient, defineForm, validateResponse, visibleBlocks } from \"@usefillo/core\";\n\nconst client = createClient({ key: \"pk_…\" }); // for syncing code-defined forms\n\nconst form = defineForm({\n id: \"cust-feedback\",\n pages: [{ id: \"p1\", blocks: [\n { id: \"email\", kind: \"email\", label: \"Work email\", required: true },\n { id: \"msg\", kind: \"long_text\", label: \"What should we know?\" },\n ] }],\n});\n```\n\nPublished renderer embeds can fetch by `formId` without a key. Use a client object for custom API origins, uploads, or submissions from your own renderer; add a publishable key only when syncing `defineForm()` schemas from code.\n\nThe full export surface — client methods, schema types, validation, conditional logic, appearance and localization contracts — is documented in the [API reference](https://fillo.so/docs/reference).\n\n## Links\n\n- **Docs:** [fillo.so/docs](https://fillo.so/docs)\n- **Website:** [fillo.so](https://fillo.so)\n\nMIT licensed.\n","readmeFilename":"README.md"}
![\"Fillo](\"https://fillo.so/brand/readme-banner.png\")
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