> For the complete documentation index, see [llms.txt](https://nfd-gg.gitbook.io/main/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nfd-gg.gitbook.io/main/eng-combine-software/section-settings/rpc-settings.md).

# RPC Settings

RPC (Remote Procedure Call) facilitates user access to the blockchain for reading/writing data, allowing other network participants to connect without the need to run their own nodes.

Any user connected to an RPC provider trusts the provider's integrity. All verification of transaction correctness occurs on the RPC provider's servers, allowing the RPC to filter out junk transactions and prevent them from clogging the sequencers.

Every RPC has a protection mechanism called Rate Limit. Rate Limit is an automatic restriction on a user who sends too many requests to the node through a specific RPC in a certain period (minute/hour/day). To reduce the load on the RPC provider's servers, access for such a user will be temporarily denied.

Public RPCs have a minimal limit, for example, up to 50-100 requests per minute. If you reach this limit, your IP will be banned, and until you change your IP or wait for the ban to be lifted (this process can take up to a day depending on the provider), the RPC will not work for you.

This limit affects the operation of Combine. If you reach the limit and get banned, your wallets' balances will stop updating, and you will not be able to start a session. Additionally, if you reach the limit during an active session, you will encounter errors in the logs until you change the RPC.

To increase this limit, we strongly recommend using private RPCs from [Ankr](https://www.ankr.com/) or other providers that offer private RPCs. You just need to register on their website, obtain these RPCs, and import them into Combine.

These providers offer a free version of private RPCs (also with request limitations) and a paid version with a higher limit. We recommend using the paid RPCs. By using paid RPCs, you will rarely encounter RPC-related issues, and your user experience with our application will be at a higher level.

Public RPCs can be found on the [Chainlist](https://chainlist.org/) website.

***

### Adding and replacing RPCs:

* After installing Combine, public RPCs will be automatically added. To change them, go to **Setting** -> **RPC Setting**;
* Find the desired network and replace the existing RPC with your custom RPC;
* If the imported RPC works correctly, click **Save** to save it.

<figure><img src="/files/tFcql97eBLwkeK2VhQY4" alt=""><figcaption><p>RPC Replacement.</p></figcaption></figure>


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