# Lifecycle of a Request

The typical lifecycle of a request is as follows:

<div data-full-width="true"><figure><img src="https://1914277788-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Fei6UAiSK3iAAi0mFH667%2Fuploads%2Fgit-blob-bb17b9b51fa3361ad54d1ac2185323f707ac8766%2FLifecycle%20of%20a%20Request.jpg?alt=media" alt=""><figcaption><p>Typical Lifecycle of a Request</p></figcaption></figure></div>

## Create a request

* The payer or payee signs the request which contains the payee, payer, currency, amount, payment details, and arbitrary content data.
* The request can be optionally encrypted such that only the payee, payer, and approved 3rd parties can view the request contents.
* The request is persisted in IPFS.
* The IPFS Content-addressable ID (CID) is stored in a smart contract on Gnosis chain

{% hint style="info" %}
Requests are *created* by storing their CIDs on Gnosis, but this doesn't mean *payment* must occur on Gnosis. *Payment* can occur on any of the supported chains including 20+ EVM-compatible chains or NEAR.
{% endhint %}

## Update a request

* The payee can optionally cancel the request or increase/decrease the expected amount.
* The payer can optionally accept the request, indicating that they intend to pay it.
* Both payee and payer can add 3rd party stakeholders if the request is encrypted.

## Pay a request

* The payer derives a paymentReference from the request contents.
* The payer calls a function on the payment network smart contract, passing in the token address, to address, amount, and paymentReference.
* An event is emitted containing the token address, to address, amount, and paymentReference.

{% hint style="info" %}
Most requests are "reference-based" meaning that a paymentReference derived from the request contents is logged on-chain via a smart contract that emits an event. Nothing gets written back to IPFS when paying a "reference-based" request.

The exception is when paying a "declarative" request, in which case, data *is* written back to IPFS. This includes when the payer declares that the payment was sent and the payee declares that the payment was received.
{% endhint %}

## Retrieve a request / Detect a payment

* The event is indexed by the payments subgraph
* An app can retrieve the request contents from IPFS and calculate the balance based on events from the payments subgraph.

{% hint style="info" %}
The request balance is calculated by adding up all the on-chain payment events with the same paymentReference. Partial payments are possible.
{% endhint %}

All of these steps are facilitated by the Request Network JavaScript SDK such that the developer needs only make a few function calls. See the [Quickstart](https://docs.request.network/advanced/request-network-sdk/get-started/quickstart-browser) to learn more.