Fillout

Build a polished form that writes to a user-owned database and supports simple branching

YES · focused build
price $19/mosubscription / year $228estimated build time one sittingreplaced by 0 people

The core loop is small enough for a capable coding agent to produce a useful local version in one sitting. For Fillout, build a polished form that writes to a user-owned database and supports simple branching. The hard boundary is excellent airtable and notion integrations, scheduling, payments, and hosted polish, plus integrations, deliverability, and workflow depth.

Build verification: not recorded. How we judge buildability

What you give up

  • excellent Airtable and Notion integrations, scheduling, payments, and hosted polish
  • advanced branching
  • payment and CRM integrations
  • large template libraries
  • enterprise compliance

Why people still pay

People still pay for Fillout because a basic form is trivial; people pay when the form feeds a dependable business workflow and never loses a response. The recurring cost buys spam control, email delivery, storage, exports, accessibility, conditional logic, and integrations, not just the visible interface.

Your build guide

The stack, security requirements, and agent rules for a focused replacement.

Before you start

  • A supported Node release, PostgreSQL, HTTPS for a shared deployment, and a backup destination. Begin with one workspace and explicit owner/member permissions.
  • Implementation components: Next.js App Router and TypeScript for server-rendered pages and validated mutations. PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace. A versioned JSON form schema shared by a controlled builder, public renderer and server-side validator.
  • Scope boundary: excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching
01
Next.js App Router and TypeScript for server-rendered pages and validated mutations.
02
PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace.
03
A versioned JSON form schema shared by a controlled builder, public renderer and server-side validator.
04
Domain model: form versions, conditional steps, external row mappings, submissions and synchronization receipts
engineering roadmap

Implementation plan

1

Phase 1

Scope and fixtures. Implement this bounded workflow: Build a branching public form that creates a row in one approved database. Validate answers locally on the server, preview field mappings and display whether each response was stored and externally synchronized. Record prerequisites, select representative user-owned fixtures and document the unsupported features: excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching

2

Phase 2

Durable model. Model form versions, conditional steps, external row mappings, submissions and synchronization receipts Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: The response is retained even if the external database is down; a retry must not create a second mapped row.

3

Phase 3

Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.

4

Phase 4

Permissions and integration failure. Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML. Apply per-form submission limits and spam controls; keep responses private and separate public form IDs from management permissions. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.

5

Phase 5

Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.

6

Phase 6

Acceptance scenarios. Submit while the connector is unavailable, then reconnect and deliver exactly one row; changing the form leaves prior responses bound to their original schema. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

the pro prompt
download AGENTS.md
WORKING SLICE
Build a branching public form that creates a row in one approved database. Validate answers locally on the server, preview field mappings and display whether each response was stored and externally synchronized.

Build this scoped Fillout-inspired workflow with a documented data model and visible failure states.

Architecture
- Next.js App Router and TypeScript for server-rendered pages and validated mutations.
- PostgreSQL with Drizzle migrations; Better Auth sessions for a small private workspace.
- A versioned JSON form schema shared by a controlled builder, public renderer and server-side validator.

Prerequisites and limits
A supported Node release, PostgreSQL, HTTPS for a shared deployment, and a backup destination. Begin with one workspace and explicit owner/member permissions.
Outside this release: excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching

Data model and correctness
form versions, conditional steps, external row mappings, submissions and synchronization receipts
Invariant: The response is retained even if the external database is down; a retry must not create a second mapped row.
Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.

Security and privacy
Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML. Apply per-form submission limits and spam controls; keep responses private and separate public form IDs from management permissions.

Recovery and export
Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching.

Implementation order
1. Phase 1 — Scope and fixtures. Implement this bounded workflow: Build a branching public form that creates a row in one approved database. Validate answers locally on the server, preview field mappings and display whether each response was stored and externally synchronized. Record prerequisites, select representative user-owned fixtures and document the unsupported features: excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching
2. Phase 2 — Durable model. Model form versions, conditional steps, external row mappings, submissions and synchronization receipts Add migrations or a versioned document format, explicit validation, stable IDs and a visible import-error report. Preserve this rule: The response is retained even if the external database is down; a retry must not create a second mapped row.
3. Phase 3 — Complete the first useful path. Implement the workflow's input, review and output interface, with clear controls and explicit empty/error states. Commit related database changes in one transaction. Use version checks for competing edits and an outbox for external notifications; retry delivery independently of saving the record.
4. Phase 4 — Permissions and integration failure. Authorize every record read and mutation on the server using its workspace membership; validate payloads, protect mutations against CSRF, and escape user-authored HTML. Apply per-form submission limits and spam controls; keep responses private and separate public form IDs from management permissions. Request integration credentials and permissions only for the enabled feature; show a disconnected state instead of mock results.
5. Phase 5 — Portable handoff. Export versioned JSON plus attachments and a readable CSV summary. Restore into a separate database and compare record IDs and attachment checksums before switching. Include setup, operating limits, fixture walkthrough and shutdown/restart instructions in the README.
6. Phase 6 — Acceptance scenarios. Submit while the connector is unavailable, then reconnect and deliver exactly one row; changing the form leaves prior responses bound to their original schema. Repeat the workflow after restart and with a denied permission or unavailable dependency; show recoverable failure rather than a success placeholder.

Acceptance
Submit while the connector is unavailable, then reconnect and deliver exactly one row; changing the form leaves prior responses bound to their original schema.
Use real source data or clearly labeled fixtures. Explain unsupported input and provider failures; do not fabricate analytics, delivery receipts, accuracy claims or security guarantees.

Optional agent guidance
Optional external skill: [web-design-guidelines](https://github.com/vercel-labs/agent-skills/blob/main/skills/web-design-guidelines/SKILL.md) — Review web interfaces for accessibility, keyboard focus, forms, navigation and interaction quality. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [vercel-composition-patterns](https://github.com/vercel-labs/agent-skills/blob/main/skills/composition-patterns/SKILL.md) — Design reusable React components with composition, context and explicit component variants. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Optional external skill: [supabase-postgres-best-practices](https://github.com/supabase/agent-skills/blob/main/skills/supabase-postgres-best-practices/SKILL.md) — Review PostgreSQL schemas, queries, indexes, pooling, concurrency and row-level security. Review its instructions and compatibility before use; it does not grant deployment, data-access or publication permission.
Project rule — data model: form versions, conditional steps, external row mappings, submissions and synchronization receipts
Project rule — preserve this invariant: The response is retained even if the external database is down; a retry must not create a second mapped row.
Project rule — acceptance evidence: Submit while the connector is unavailable, then reconnect and deliver exactly one row; changing the form leaves prior responses bound to their original schema.

$ open in your agent (prompt prefilled, you press enter), copy the prompt or copy or download AGENTS.md

share on X ↗

Alternatives to building your own

BaserowAirtable's database half with public forms and your own disk underneath5.4kaug 2026open source↗

no votes, no pay-to-list · just what's real

Fillout pricing

planmonthlyannual (per mo)what you get
free$0/workspace$0/workspaceUnlimited forms, seats, questions and file uploads; 1,000 responses/month; 20MB maximum file size; Fillout branding
starter$19/workspace$15/workspace2,000 responses/month and 20MB maximum file size; unlimited forms, seats, questions and uploadsAnnual price is $180/year; monthly total is $228/year at $19/month.
pro$49/workspace$40/workspace5,000 responses/month; unlimited forms and seatsAnnual price is $480/year.
business$89/workspace$75/workspaceUnlimited responses, at least 1GB maximum file size, custom domain, unlimited forms and seatsAnnual price is $900/year.
enterprise——1 million+ database records, unlimited workflow runs, unlimited forms, seats and responsesCustom quote.

free tierUnlimited forms, seats, questions and file uploads; 1,000 responses/month; 20MB maximum file size; Fillout branding

billingmonthly + annual prepaid (-20%)

hidden costsFillout says responses continue to be collected after the monthly cap, but the account must upgrade, buy unpublished bulk-submission capacity or wait for reset to use them; Conversion Kit is a separately sold add-on with no public rate.

pricing sources checked 2026-08-12 · pricing source ↗

Questions about Fillout

Can you build your own Fillout with AI?

The verdict is yes for the scoped workflow. The core loop is small enough for a capable coding agent to produce a useful local version in one sitting. For Fillout, build a polished form that writes to a user-owned database and supports simple branching. The hard boundary is excellent airtable and notion integrations, scheduling, payments, and hosted polish, plus integrations, deliverability, and workflow depth.

What does the Fillout build prompt cover?

The prompt starts with this scope: Build a branching public form that creates a row in one approved database. Validate answers locally on the server, preview field mappings and display whether each response was stored and externally synchronized. Full-product capabilities excluded from the comparison include: excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching; payment and CRM integrations. Follow the implementation plan and its prerequisites before expanding the build.

How do I use the prompt, AGENTS.md and agent skills?

Start with the Fillout prerequisites and stack, then copy the prompt into your coding agent. Save the project rules as AGENTS.md in the project root. Linked skills are optional packages or source instructions for specific tasks; review their current contents and install only those matching the chosen stack. A skill does not supply API credentials or verify the finished app.

How long will this Fillout project take?

The catalogue estimate is one sitting for the limited scope. Setup, integration approvals, debugging, deployment and ongoing maintenance can add time. This is an estimate, not a delivery guarantee.

What would I give up by replacing Fillout?

excellent Airtable and Notion integrations, scheduling, payments, and hosted polish; advanced branching; payment and CRM integrations; large template libraries; enterprise compliance. People still pay for Fillout because a basic form is trivial; people pay when the form feeds a dependable business workflow and never loses a response. The recurring cost buys spam control, email delivery, storage, exports, accessibility, conditional logic, and integrations, not just the visible interface.

What price is this guide comparing against?

The recorded Starter plan is $19/mo (monthly), checked 2026-07-31. Check the linked pricing source before buying. Building your own also has hosting, API and maintenance costs; the recorded amount is not a guaranteed saving.

What can I use instead of building Fillout?

Baserow: Airtable's database half with public forms and your own disk underneath. Check each option's license, hosting needs and feature limits.

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