> ## Documentation Index
> Fetch the complete documentation index at: https://lnurl.dev/llms.txt
> Use this file to discover all available pages before exploring further.

<AgentInstructions>
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  ## Submitting Feedback
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# LUD-09: `successAction` field for `payRequest`.

> Display inline code and code blocks

`author: rossdyson` `author: akumaigorodski` `discussion: https://t.me/lnurl/256`

***

## Standardization of the `successAction` field

This defines a field `successAction` returned by the `SERVICE` along with the payment request in the second callback.

It must be stored by the `WALLET` and shown to the user as soon as a payment succeeds.

To implement this, a `SERVICE` must alter its JSON response to the second callback to include it like the following:

```diff  theme={null}
 {
     "pr": string,
     "routes": [],
+   "successAction": Object
 }
```

In which Object has the format:

```Typescript  theme={null}
{
   tag: string, // action type
   ...rest of fields depends on tag value
}
```

This document defines the *message* and the *url* types. See examples:

```JSON  theme={null}
{
  "tag": "message",
  "message": "Thank you for using bike-over-ln co! Your rental bike is unlocked now" // Up to 144 characters
}
```

```JSON  theme={null}
{
   "tag": "url",
   "description": "Thank you for your purchase. Here is your order details", // Up to 144 characters
   "url": "https://www.ln-service.com/order/<orderId>" // url domain must be the same as `callback` domain at step 3
}
```

### LNURL-pay flow change

A `WALLET` that decides to implement this scheme must, after a payment is complete and a `successAction` is present, show a popup or screen to the user with the contents of that `successAction`.

For *message*, a toaster or popup is sufficient. For *url*, the wallet should give the user a popup which displays `description`, `url`, and a 'open' button to open the `url` in a new browser tab.

`WALLET` should also store `successAction` data on the transaction record.

### Support for `successAction` types

Since other `successAction` types can be added in the future, if a `successAction` is present in the response from `SERVICE`, a `WALLET` must make sure that its `tag` value is of a kind it supports, otherwise it must not proceed with the payment -- or the user might end up paying and not seeing its expected `successAction`.


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