Connect Instafill.ai to ChatGPT with MCP
Fill out PDF forms directly from ChatGPT. Connect once and ask ChatGPT to find, fill out, and download your forms using natural language.
Overview
MCP (Model Context Protocol) is an open standard that enables AI assistants to securely connect to external data sources and tools. The Instafill.ai form filler MCP server implements this protocol to give ChatGPT direct access to your Instafill.ai workspace - your forms, your profiles, and your fill history - without leaving the chat window.
Once connected, you can ask ChatGPT things like:
- "Show me all my forms"
- "Fill out the DS-11 form with my data"
- "Download the filled form from session abc-123"
ChatGPT handles the rest. It finds the right form, opens a secure widget for your data, tracks the fill job, and gives you a download link when it is done.
Before You Start
You need:
- A ChatGPT Plus, Team, or Enterprise account (not available on the free plan)
- An Instafill.ai account
- Developer mode enabled in ChatGPT
Setup: Connect Instafill.ai to ChatGPT
Step 1 - Enable Developer Mode in ChatGPT
Open ChatGPT and go to Settings > Apps > Advanced settings. Toggle Developer mode on.
Developer mode is what unlocks the ability to add custom MCP apps in ChatGPT. It is available on Plus, Team, and Enterprise - not on the free plan.
Step 2 - Create a New App
Inside the same Apps section, click "Create App".
Step 3 - Configure the App
Fill in the following:
| Field | Value |
|---|---|
| Name | Autofill PDF |
| Description | Fill out PDF forms with Instafill.ai (optional) |
| MCP Server URL | https://mcp.instafill.ai/mcp |
| Authentication | OAuth |
Check the "I understand and want to continue" checkbox, then click "Create".
Step 4 - Authenticate with Instafill.ai
After creating the app, follow the OAuth flow:
- If you already have an Instafill.ai account - log in
- If you are new - sign up for free right in the flow
- Select the workspace you want ChatGPT to access
- Grant the AI assistant permission to access your forms
That is it. The connection is live.
How to Use It
Once connected, just type naturally in ChatGPT. Here are some things you can ask:
Browse your forms:
"List all my forms" "Find the W-4 form" "Show me all my filled forms"
Fill out a form:
"Fill out the I-9 form with my information"
ChatGPT will open a secure widget where you enter your data or select a saved profile. Your data goes directly to Instafill.ai and is not stored in your ChatGPT conversation.
Download a completed form:
"Download the form I just filled out" "Get the PDF for session abc-123"
ChatGPT returns a download link. Download links are valid for 10 minutes.
Manage profiles:
"Create a new profile" "Show me my saved profiles"
What ChatGPT Can Do with Your Instafill.ai Workspace
The integration gives ChatGPT access to 16 tools across your workspace:
| What you can do | How to ask ChatGPT |
|---|---|
| See all form templates | "List my forms" |
| Find a specific form | "Find the W-9 form" |
| See completed fill jobs | "Show my filled forms" |
| Fill out a form | "Fill out the W-9 with my data" |
| Check fill status | "Is my form ready?" |
| Download a filled form | "Download the completed form" |
| Upload a new form | "I want to upload a new form" |
| Create a profile | "Create a new profile" |
| View profile details | "Show me my saved profiles" |
How Form Filling Works in ChatGPT
ChatGPT uses a secure widget to collect your data. This is different from how it works in Claude Desktop or Claude.ai, where you provide data directly in the chat.
In ChatGPT, your form data is entered in a dedicated widget that sits outside the conversation. This means:
- Your data is not stored in chat history
- The widget transmits data directly to Instafill.ai servers
- The widget session expires after 10 minutes if not submitted
When you ask ChatGPT to fill out a form, it opens the widget automatically. You will see two options:
- Text Data - type or paste your information directly
- Profile - select a saved profile as the data source
After you submit the widget, ChatGPT tracks the fill job and returns your download link when it is ready.
Use Cases
| Who | What they use it for |
|---|---|
| Healthcare staff | Fill out patient intake forms and CMS-1500 claims directly from ChatGPT |
| Legal teams | Fill out court forms and client intake documents |
| HR and operations | Fill out I-9, W-4, and onboarding forms using saved employee profiles |
| Construction | Fill out prequalification packets stored in Instafill.ai |
| Immigration attorneys | Fill out USCIS form packets using saved client profiles |
Also Available in Claude and Claude Code
If you use Claude Desktop, Claude.ai, or Claude Code CLI, you can connect the same Instafill.ai MCP server there too.
Go to Settings > Connectors > Add Custom Connector and enter:
https://mcp.instafill.ai/mcp
Claude users get the same 16 tools, with one difference: instead of the widget, Claude uses the fill_form tool - you provide your data directly in chat, and Claude fills out the form without opening a separate widget.
Full setup instructions for Claude and Claude Code are in Instafill.ai MCP Server Documentation.
Common Questions
Do I need a paid ChatGPT plan?
Yes. Developer mode - which is required to add custom MCP apps - is only available on ChatGPT Plus, Team, and Enterprise. It is not available on the free plan.
Does Instafill.ai need to be set up before I connect?
No. If you do not have an Instafill.ai account yet, you can create one for free during the OAuth authentication step.
Is my form data secure?
Yes. The OAuth flow means ChatGPT never sees your Instafill.ai password. Data you enter in the fill widget is transmitted directly to Instafill.ai servers and is not stored in your ChatGPT conversation. Learn more at Instafill.ai Security.
Can ChatGPT access forms from all my workspaces?
During setup, you select one workspace to connect to. ChatGPT will only see forms and profiles from that workspace.
The fill widget did not open. What do I do?
Make sure Developer mode is still enabled in your ChatGPT settings. Widget sessions expire after 10 minutes - if yours timed out, ask ChatGPT to fill out the form again and a new widget will open.
Can I use this with Claude instead of ChatGPT?
Yes. The same MCP server URL works in Claude Desktop, Claude.ai, and Claude Code CLI. See https://mcp.instafill.ai/docs for step-by-step instructions.
What happens if I revoke access?
You can revoke MCP access at any time from your Instafill.ai account settings. You can also remove the app from the ChatGPT Apps section in Settings.