Fillo

Product Introduction

1. Definition: Fillo is a headless form infrastructure platform and API-first service designed for modern web development teams. It falls into the technical categories of form backend-as-a-service (BaaS), developer tools, and low-code/no-code workflow automation.
2. Core Value Proposition: Fillo exists to eliminate the manual, repetitive engineering work involved in building, maintaining, and scaling forms within a product. Its core value is providing a robust, scalable backend for forms while allowing developers to retain full control over the frontend user interface, styling, and user context. This enables faster iteration, reduces technical debt, and centralizes form logic and data management.

Main Features

1. Headless Form Rendering: Fillo provides SDKs for React, Next.js, Vue, Svelte, Astro, and plain JavaScript that render accessible HTML form controls directly into your application's components. How it works: Developers define a form schema in Fillo's dashboard or via its Management API. The SDK fetches this schema and renders the corresponding inputs (text fields, file uploads, selects, etc.) while allowing complete visual customization via the host app's CSS and design system. This separates the form's logic and data layer from its presentation.
2. AI Agent & CLI Integration: Fillo is built for integration with AI coding agents (like Cursor, GitHub Copilot, or Claude Code) and developer workflows. How it works: It provides agent-specific documentation (llms.txt, agent-examples.md), a Model Context Protocol (MCP) server for remote tool access, and a local MCP server via npm. The official CLI (@usefillo/cli) allows for local development and automation. This enables an AI agent to provision a form, embed it into code, and preview it in real-time.
3. Unified Form Lifecycle Management: Fillo manages the entire lifecycle of a form beyond just collection. How it works: It handles validation logic, versioning (allowing drafts to be edited while published forms remain live), response storage, and file upload management. Uploads can be configured for direct-to-cloud storage (Google Drive, Box, Amazon S3, Cloudflare R2) with Fillo maintaining the metadata and reference. Responses can be reviewed, exported via CSV, or processed through webhooks and the Management API.

Problems Solved

1. Pain Point: The high development cost and maintenance overhead of building custom, product-integrated forms. Traditional form builders often create isolated, stylistically mismatched widgets, while custom-coded forms require rebuilding validation, file handling, and data pipelines for every use case.
2. Target Audience: The primary users are product engineering teams and full-stack developers working with modern JavaScript frameworks (React, Vue, Svelte). Secondary users are product managers and operations teams who need to deploy and manage forms (like intake or feedback forms) without relying on engineering for every change.
3. Use Cases: Essential scenarios include user onboarding flows that require app context, in-app feedback/support forms, file request and approval systems, customer intake forms that need to match the product's brand, and any form that must be repeated across multiple pages or environments within the same application.

Unique Advantages

1. Differentiation: Unlike monolithic form builders (e.g., Typeform, Jotform) that host the form UI on their domain, Fillo is headless, giving developers full UI control. Compared to building from scratch, it provides a complete, managed backend. Unlike some headless services, it deeply integrates with AI coding agents and offers both visual and code-defined authoring workflows.
2. Key Innovation: Its deep, native integration with AI coding agents via tailored documentation, MCP servers, and a CLI is a significant innovation. This positions Fillo not just as a tool for developers, but as a component an AI agent can reliably implement, dramatically reducing the friction of initial adoption and ongoing edits within a codebase.

Frequently Asked Questions (FAQ)

1. What is headless form infrastructure? Headless form infrastructure is a backend service that provides all the logic, data storage, and management for forms through an API, while allowing developers to build and control the frontend user interface (the "head") completely independently using their own technology stack and design system.
2. How does Fillo handle file uploads and storage? Fillo can handle file uploads by either storing them on its own infrastructure or, for larger files, facilitating direct, browser-based uploads to your connected cloud storage provider such as Amazon S3, Google Drive, Box, or Cloudflare R2. Fillo then stores the file metadata and reference linked to the form response for unified management.
3. Can I use Fillo with my existing React or Vue.js application? Yes, Fillo provides dedicated SDKs for React, Vue, Svelte, Astro, and Next.js, as well as a plain JavaScript/DOM library. You install the SDK, embed the form components or hooks into your existing app, and style them with your application's CSS, allowing the form to seamlessly inherit your route and user context.
4. What is the Fillo MCP server and how do I use it? The Fillo Model Context Protocol (MCP) server allows AI coding agents that support MCP (like Claude Desktop) to directly interact with your Fillo forms and data. You can use the remote server or install the local npm package (@usefillo/mcp), enabling your agent to read schemas, create forms, and fetch responses as context for its coding tasks.
5. How does form versioning work in Fillo? Fillo maintains version history for your forms. When you edit a published form, you work on a draft version. The previously published version remains live and continues to collect responses. Once you publish the new draft, it replaces the old version, but all historical responses remain accessible and are tagged with the version of the form that was active when they were submitted.