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Functions let you build powerful backend logic by turning your words into code. They handle powerful operations while keeping your UI clean and focused.

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Why Use Functions

Functions offer several key benefits:
  • Turn words into logic - Describe what you want in plain language and Create generates the code
  • Separate UI from Logic - Keep pages focused on presentation while Functions handle powerful operations
  • Test in Isolation - Debug and perfect logic independently from your UI
  • Reuseable - Use Functions across pages and components once they’re working
  • External APIs - Functions can connect securely to thousands of APIs using Secrets
  • Composeable - Build powerful features by combining Functions with Integrations, Databases, and other Functions
For example, imagine building an app that analyzes documents with AI: Without Functions, you would need to handle everything in one place:
  • Upload interface for PDFs
  • Code to display the document
  • AI analysis of images
  • AI text summarization
  • Error messages
  • Loading screens
With Functions, you can split this into simpler parts: Page:
  • A clean upload interface
  • Document display
  • A button that calls your analysis Function
Function:
  • AI image analysis
  • AI text summarization
  • Error handling
This separation makes your app easier to build, test, and maintain.

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Creating Functions

Create Functions in several ways:
  • Logo Menu > New Function
  • Press option-F (or alt-F on Windows)
  • Type / in chat > Create Function

Creating a new Function

Describe what you want the Function to do:
  • What inputs it needs
  • What logic it should perform
  • What outputs it should return
Create generates:
  • A flow diagram showing the Function’s logic
  • The underlying serverless code (viewable in the “Code” tab)
  • Input/output interfaces

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Making Functions that Work

When building Functions:
  • For external APIs, find their documentation first. You can paste API endpoint URLs directly into the Function chat - Create will analyze the screenshot and write the code.
  • If you get test errors, paste the error message back into your Function definition. Create often knows how to fix the specific issue.

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Using Integrations, Databases, and Other Functions

Make your Functions more powerful by combining them with:
  • Integrations - Add AI capabilities and other features
  • Databases - Store and retrieve data
  • Other Functions - Chain multiple Functions together
To use these in your Function:
  1. Type / or open the Add-ons menu
  2. Select the Integration, Database, or Function
  3. Describe how you want to use it

Using an integration in a Function

For example, you could build a Function that:
  • Uses ChatGPT to analyze text
  • Stores results in a database
  • Calls another Function to notify users
Create handles connecting everything together based on your description. If you need specific behavior, add more details to your prompt about how you want the pieces to interact.

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Testing Functions

Every Function has a full test runner available in the 3-dot menu > Run Test tab.

Accessing the test runner

Use it to:
  • Sample Inputs - Enter test data as Form or JSON
  • Run Tests - Execute the Function with your inputs
  • View Results - See outputs or error messages
  • Debug - Use error descriptions to fix issues. You can often just paste the error description into your prompt to fix it.
Functions have a 5-minute timeout. Chain Functions together for longer operations.

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Using Functions

Add Functions to pages, components, or other Functions:
  • Type / in chat
  • Select your Function
  • Describe how you want to use it

Using a Function

Create handles:
  • Connecting inputs/outputs
  • Error states
  • Loading indicators
  • UI integration

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Updating Functions

After changing a Function:
  1. Find where you integrated it
  2. Click “Update” next to the integration
  3. Create will refresh with latest changes
Changes to Functions don’t automatically update everywhere they’re used. This prevents unwanted changes from breaking your app.

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External APIs and Secrets

Functions can connect to any external API. To use an API:
  1. Store authentication details (API keys, tokens) as Secrets
  2. Tell Create which API to use - it will handle the integration
  3. Test carefully since calls hit live APIs
Popular APIs and where to find credentials: Here is an in-depth YouTube video tutorial on how to connect to an external API, using the Exa AI Search API:
You can also use Zapier, Make, and other platforms that connect to APIs by using their “webhook” triggers. Here’s a YouTube video with the steps:

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Secrets

Secrets securely store sensitive data like API keys and passwords. They’re available to all Functions in your project. To add a Secret:
  1. Open the “Secrets” panel from the 3-dot menu at the top of chat in any Function
  2. Click ”+ Add a new secret”
  3. Name it clearly (e.g. “Stripe API Key”)
  4. Enter the secret value
Create automatically uses well-named secrets when generating Function code. For example, if you have a “Stripe API Key” secret and mention Stripe in your prompt, Create will use that key securely.
When using popular APIs like Stripe or Twilio, Create will often ask for specific secret names in chat (e.g. “Stripe Secret Key”). Use these as hints for what credentials you need.
Supported secret types:
  • API Keys
  • Access Tokens
  • Basic Auth Credentials
  • Bearer Tokens
OAuth tokens aren’t supported since they require refresh flows.

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Publishing

When ready to launch:
  1. Click Publish in top right
  2. Choose Functions to publish
  3. Set routes if needed (all Function routes start with /api)
  4. Enable/disable as needed
Published Functions are locked versions your published app uses. Continue development without breaking live features.
Need help? Join our Discord and post in #help-me-build