Capacitor Firebase Cloud Functions Plugin

Unofficial Capacitor plugin for Firebase Cloud Functions.[^1]

Use Cases

The Firebase Cloud Functions plugin is typically used to run backend logic from your Capacitor app without managing your own server, for example:

• Serverless backend logic: Call callable Cloud Functions by name to run trusted server-side code from your app.
• Structured data exchange: Pass strings, numbers, booleans, arrays, and objects to a function and process the returned result.
• Custom domains and regions: Call functions that are deployed in a specific region or hosted on a custom domain by their URL.
• Local development: Test your functions against the Cloud Functions emulator before deploying them to production.

Compatibility

Guides

• Call Firebase Cloud Functions from a Capacitor App: Call serverless backend logic by name or URL, including local emulator testing, with this plugin.
• How to Use Firebase in a Capacitor App: Which plugins pair naturally with your backend logic, from sign-in to the database it reads.

Installation

You can use our AI-Assisted Setup to install the plugin. Add the Capawesome Skills to your AI tool using the following command:

npx skills add capawesome-team/skills --skill capacitor-plugins

Then use the following prompt:

Use the `capacitor-plugins` skill from `capawesome-team/skills` to install the `@capacitor-firebase/functions` plugin in my project.

If you prefer Manual Setup, install the plugin by running the following commands and follow the platform-specific instructions below:

npm install @capacitor-firebase/functions
npx cap sync

Add Firebase to your project if you haven't already (Android / iOS).

Android

Variables

If needed, you can define the following project variable in your app’s variables.gradle file to change the default version of the dependency:

• $firebaseFunctionsVersion version of com.google.firebase:firebase-functions (default: 22.1.0)

This can be useful if you encounter dependency conflicts with other plugins in your project.

iOS

Swift Package Manager

Add the following to your capacitor.config.json (or capacitor.config.ts) to avoid a SwiftPM package identity collision:

{
  "experimental": {
    "ios": {
      "spm": {
        "packageOptions": {
          "@capacitor-firebase/functions": {
            "symlink": true
          }
        }
      }
    }
  }
}

Attention: SPM packageOptions support requires Capacitor CLI 8.4.0+.

Configuration

No configuration required for this plugin.

Demo

A working example can be found here: robingenz/capacitor-firebase-plugin-demo

Usage

The following examples show how to call Cloud Functions by name or by URL and how to connect to the Cloud Functions emulator.

Call a function by name

Call a callable Cloud Function by its name. You can pass strings, numbers, booleans, arrays, and objects as data and receive the result of the function in the data property. Use the region option if your function is not deployed in the default region:

import { FirebaseFunctions } from '@capacitor-firebase/functions';

const callByName = async () => {
    const { data } = await FirebaseFunctions.callByName({
        name: 'helloWorld',
        data: {
            string: 'Hello World!',
            number: 123,
            boolean: true,
            array: [1, 2, 3],
            object: {
                key: 'value'
            }
        }
    });
    return data;
};

Call a function by URL

If your callable function is hosted on a custom domain or you prefer to address it directly, call it by its URL:

import { FirebaseFunctions } from '@capacitor-firebase/functions';

const callByUrl = async () => {
    const { data } = await FirebaseFunctions.callByUrl({
        url: 'https://us-central1-YOUR_PROJECT_ID.cloudfunctions.net/helloWorld',
        data: {
            string: 'Hello World!',
            number: 123,
            boolean: true,
            array: [1, 2, 3],
            object: {
                key: 'value'
            }
        }
    });
    return data;
};

Use the Cloud Functions emulator

During development, you can instrument your app to talk to the local Cloud Functions emulator. When using an Android emulator device, 10.0.2.2 is the special IP address to connect to the localhost of the host computer. Note that on Android, the cleartext traffic must be allowed, which is not intended for use in production:

import { FirebaseFunctions } from '@capacitor-firebase/functions';

const useEmulator = async () => {
  await FirebaseFunctions.useEmulator({
    host: '10.0.2.2',
    port: 9001,
  });
};

API

• callByName(...)
• callByUrl(...)
• useEmulator(...)
• Interfaces
• Type Aliases

callByName(...)

callByName<RequestData = unknown, ResponseData = unknown>(options: CallByNameOptions<RequestData>) => Promise<CallByNameResult<ResponseData>>

Call a callable function by name.

Returns: Promise<CallByNameResult<ResponseData>>

Since: 6.1.0

callByUrl(...)

callByUrl<RequestData = unknown, ResponseData = unknown>(options: CallByUrlOptions<RequestData>) => Promise<CallByUrlResult<ResponseData>>

Call a callable function by URL.

Returns: Promise<CallByUrlResult<ResponseData>>

Since: 6.1.0

useEmulator(...)

useEmulator(options: UseEmulatorOptions) => Promise<void>

Instrument your app to talk to the Cloud Functions emulator.

On Android, the cleartext traffic must be allowed. On the Capacitor configuration:

{
  server: {
    cleartext: true
  }
}

The cleartext traffic is not intended for use in production.

Since: 6.1.0

Interfaces

CallResult

CallByNameOptions

CallByUrlOptions

UseEmulatorOptions

Type Aliases

CallByNameResult

CallResult<ResponseData>

CallByUrlResult

CallResult<ResponseData>

FAQ

What is the difference between callByName and callByUrl?

The callByName(...) method calls a callable function by its name and, optionally, its region. The callByUrl(...) method calls a callable function by its full URL instead, which is useful if the function is hosted on a custom domain.

What data types can I pass to a callable function?

You can pass strings, numbers, booleans, arrays, and nested objects as data to a callable function. The result of the function is returned in the data property of the call result.

How do I test my functions locally?

Use the useEmulator(...) method to instrument your app to talk to the local Cloud Functions emulator, as shown in the usage example above. When testing on an Android emulator device, use 10.0.2.2 as the host to reach the localhost of the host computer. Keep in mind that on Android, the cleartext traffic must be allowed for this, which is not intended for use in production.

Why do I get a SwiftPM package identity collision on iOS?

This is a known issue when using the plugin with Swift Package Manager. Add the symlink package option for @capacitor-firebase/functions to your Capacitor configuration as described in the Installation section. Note that SPM packageOptions support requires Capacitor CLI 8.4.0 or later.

Can I use this plugin with Ionic, React, Vue or Angular?

Yes, the plugin is framework-agnostic. It works in any Capacitor app regardless of the web framework, including Ionic with Angular, React, or Vue, as well as plain JavaScript projects.

Related Plugins

• Firebase Authentication: Sign in users with Firebase Authentication.
• Firebase Cloud Firestore: Store and sync app data in Cloud Firestore.
• Firebase Cloud Storage: Upload and download files with Firebase Cloud Storage.

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Changelog

See CHANGELOG.md.

License

See LICENSE.

[^1]: This project is not affiliated with, endorsed by, sponsored by, or approved by Google LLC or any of their affiliates or subsidiaries.