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Overview

Functions module for invoking custom backend functions. This module allows you to invoke the custom backend functions defined in the app.

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Authentication Modes

This module is available to use with a client in all authentication modes:
  • Anonymous or User authentication (base44.functions): Functions are invoked with the current user’s permissions. Anonymous users invoke functions without authentication, while authenticated users invoke functions with their authentication context.
  • Service role authentication (base44.asServiceRole.functions): Functions are invoked with elevated admin-level permissions. The function code receives a request with admin authentication context.

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Generated Types

If you’re working in a TypeScript project, you can generate types from your backend functions to get autocomplete on function names when calling invoke(). See the Dynamic Types guide to get started.

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Methods

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invoke()

invoke(functionName, data?): Promise<any>
Invokes a custom backend function by name. Sends a POST request to a custom backend function deployed to the app. The function receives the provided data as named parameters and returns the result. If any parameter is a File object, the request will automatically be sent as multipart/form-data. Otherwise, it will be sent as JSON. For streaming responses, non-POST methods, or raw response access, use fetch() instead.

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Parameters

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functionName
string
required
The name of the function to invoke.
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data
Record<string, any>
An object containing named parameters for the function.

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Returns

Promise<any> Promise resolving to the function’s response. The data property contains the data returned by the function, if there is any.

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Examples

const result = await base44.functions.invoke('calculateTotal', {
  items: ['item1', 'item2'],
});
console.log(result.data.total);

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fetch()

fetch(path, init?): Promise<Response>
Performs a direct HTTP request to a backend function path and returns the native Response. Use fetch() when you need low-level control that invoke() doesn’t provide, such as:
  • Streaming responses, like SSE, chunked text, or NDJSON
  • Custom HTTP methods, like PUT, PATCH, or DELETE
  • Raw response access, including status codes, headers, and binary bodies

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Parameters

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path
string
required
Function path. Leading slash is optional, so /chat and chat are equivalent. For example, '/streaming_demo' or 'reports/export'.
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init
RequestInit
Optional RequestInit options such as method, headers, body, and signal. Auth headers are added automatically.

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Returns

Promise<Response> Promise resolving to a native Response.

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Examples

const response = await base44.functions.fetch('/chat', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ prompt: 'Hello!' }),
});

const reader = response.body!.getReader();
const decoder = new TextDecoder();

while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  console.log(decoder.decode(value, { stream: true }));
}

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Type Definitions

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FunctionName

FunctionName = keyof FunctionNameRegistry extends never ? string : keyof FunctionNameRegistry
Union of all function names from the FunctionNameRegistry. Defaults to string when no types have been generated.

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Example

// With generated types, you get autocomplete on function names
await base44.functions.invoke('calculateTotal', { items: ['item1', 'item2'] });

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FunctionNameRegistry

Registry of function names. The types generate command fills this registry, then FunctionName resolves to a union of the keys.