# Solana RPC Methods

#### **State Commitment Configuration Summary**

Solana nodes use a **commitment level** set by the client to decide which bank state to query during preflight checks and transaction processing. Commitment levels reflect how finalized a block is and affect how likely that state is to change.

**Available commitment levels (from most to least finalized):**

* **finalized**: Block confirmed by a supermajority and considered final (maximum lockout).
* **confirmed**: Block directly voted on by a supermajority, based on gossip and replay; supports optimistic confirmation.
* **processed**: Most recent block seen by the node; may be skipped by the cluster.

**Recommendations:**

* Use **confirmed** for processing dependent transactions (balance of speed and safety).
* Use **finalized** for maximum safety against rollback.
* **Default** is **finalized** if no commitment is specified.
* Only API methods that query bank state accept the `commitment` parameter, as indicated in the API reference.

#### **RPC Response Structure**

Many methods that take a commitment parameter return an RpcResponse JSON object comprised of two parts:

* `context` : An RpcResponseContext JSON structure including a `slot` field at which the operation was evaluated.
* `value` : The value returned by the operation itself.

#### **Parsed Responses**

Some methods support an `encoding` parameter, and can return account or instruction data in parsed JSON format if `"encoding":"jsonParsed"` is requested and the node has a parser for the owning program. 

#### **Filter Criteria Summary**

Some RPC methods allow a `filters` object to pre-filter program account data returned in the response.

**Supported filters:**

* **memcmp**: Compares a specific byte sequence at a given offset within the account data.
  * `offset` *(usize)*: Position in the data to begin comparison.
  * `bytes` *(string)*: The byte sequence to match (encoded).
  * `encoding` *(string)*: `"base58"` or `"base64"` encoding.

    > ⚠️ `base64` support is only available in **solana-core v1.14.0+**. Omit this field when querying older nodes.
* **dataSize** *(u64)*: Matches accounts with a specific data length.

These filters help reduce unnecessary data by only returning accounts that meet the specified criteria.