---
id: on
title: "Subscribing: on()"
slug: on
---

import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

Subscribe to realtime changes in your databse.

<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('*')
  .on('*', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

## Parameters


<ul className="method-list-group">
  
<li className="method-list-item">
  <h4 className="method-list-item-label">
    <span className="method-list-item-label-name">
      event
    </span>
    <span className="method-list-item-label-badge required">
      required
    </span>
    <span className="method-list-item-validation">
      INSERT | UPDATE | DELETE | *
    </span>
  </h4>
  <div class="method-list-item-description">

The database event which you would like to receive updates for, or you can use the special wildcard `*` to listen to all changes.
  
  </div>
  
</li>


<li className="method-list-item">
  <h4 className="method-list-item-label">
    <span className="method-list-item-label-name">
      callback
    </span>
    <span className="method-list-item-label-badge required">
      required
    </span>
    <span className="method-list-item-validation">
      object
    </span>
  </h4>
  <div class="method-list-item-description">

A callback that will handle the payload that is sent whenever your database changes.
  
  </div>
  
</li>

</ul>


## Notes

- If you want to receive the "previous" data for updates and deletes, you will need to set `REPLICA IDENTITY` to `FULL`, like this: `ALTER TABLE your_table REPLICA IDENTITY FULL;`










## Examples

### Listen to all database changes



<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('*')
  .on('*', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

### Listening to a specific table



<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('countries')
  .on('*', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

### Listening to inserts



<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('countries')
  .on('INSERT', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

### Listening to updates



<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('countries')
  .on('UPDATE', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

### Listening to deletes



<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('countries')
  .on('DELETE', payload => {
    console.log('Change received!', payload)
  })
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>

### Listening to multiple events

You can chain listeners if you want to listen to multiple events for each table.

<Tabs
  groupId="libraries"
  values={[{ label: 'JavaScript', value: 'js' },{ label: 'Python', value: 'py' }]}>

<TabItem value="js">

```js
const mySubscription = supabase
  .from('countries')
  .on('INSERT', handleRecordInserted)
  .on('DELETE', handleRecordDeleted)
  .subscribe()
```


</TabItem>
<TabItem value="py">

```py
# Not yet implemented
```


</TabItem>

</Tabs>