> ## Documentation Index
> Fetch the complete documentation index at: https://support.quo.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Deep linking
> Enable users to call and message directly from your mobile app using Quo, formerly OpenPhone, deep links
## Overview
Deep linking allows your mobile app users to call and text through Quo without leaving your app. Create seamless communication experiences by integrating Quo's URL schemes into your mobile application.
Deep linking is available for mobile apps only. Web and desktop applications are not supported.
## Use cases
**Deep linking is ideal for:**
* Customer service apps with call functionality
* Business apps requiring direct communication
* CRM mobile applications
* Field service and delivery apps
* Any mobile app with communication features
## Dialing phone numbers
### URL scheme format
```
openphone://dial?number=&from=&action=call
```
### Parameters
**Required:**
* `number`: URL-encoded phone number string
**Optional:**
* `from`: URL-encoded Quo number to use as caller ID
* `action`: Set to `call` for automatic dialing
If `from` is not specified, the currently selected Quo number is used. For automatic calling with multiple numbers, specify `from` to avoid number selection prompts.
### Examples
**Basic dialing:**
```
openphone://dial?number=4107934326
openphone://dial?number=%2B14107934326
```
**Automatic calling:**
```
openphone://dial?number=4107934326&from=3239991234&action=call
```
## Drafting messages
### URL scheme format
```
openphone://message?number=&from=&text=&attachments=,
```
### Parameters
**All parameters are optional:**
* `number`: URL-encoded phone number string
* `from`: URL-encoded Quo number to send from
* `selectedAsFallback`: Use current number when `from` not set (default: false)
* `text`: URL-encoded message body
* `attachments`: Comma-separated URLs to files with proper extensions (.jpg, .pdf, etc.)
### Examples
**Simple message:**
```
openphone://message?text=Hello,%20buddy
```
**Message with attachments:**
```
openphone://message?number=4107934326&text=Hello,%20buddy&attachments=https%3A%2F%2Fexample.com%2Ffile.pdf,https%3A%2F%2Fexample.com%2Fimage.png
```
## Group communications
### Multiple recipients
Both dialing and messaging support multiple recipients by providing comma-separated phone numbers:
**Group messaging:**
```
openphone://message?number=4107934326,9801235640&text=Hello
```
**Group calling:**
```
openphone://dial?number=4107934326,9801235640&action=call
```
### Limitations and requirements
**Group size limits:**
* Maximum **9 phone numbers** per group (user is the 10th participant)
* For group dialing, `action=call` parameter is required
**Direct numbers:**
* User direct numbers start with `@` symbol
* Must be URL-encoded: `@9997934326` becomes `%409997934326`
Group dialing requires the `action=call` parameter when multiple numbers are provided.
## User experience
### App behavior
**When users tap deep links:**
* **App installed**: Quo launches with pre-filled dialer or message composer
* **App not installed**: Redirects to App Store (iOS) or Google Play Store (Android)
* **Multiple numbers available**: User may be prompted to select calling number
### Implementation tips
**Best practices:**
* Always URL-encode phone numbers and message content
* Test deep links on both iOS and Android devices
* Handle fallback scenarios when Quo isn't installed
* Consider user experience for number selection prompts
**URL encoding examples:**
* Space: `%20`
* Plus sign: `%2B`
* At symbol: `%40`
* Comma: `%2C`