Lightweight, ergonomic Solana JSON-RPC client for wasm.

Install

cargo add spume                       # HTTP RPC only
cargo add spume --features pubsub     # + WebSocket subscriptions

The pubsub feature is off by default — opt in only if you need WebSocket subscriptions. HTTP-only consumers ship a smaller wasm bundle.

HTTP usage

use spume::WasmClient;

let client = WasmClient::new("https://api.mainnet-beta.solana.com");

let slot    = client.get_slot(None).await?;
let version = client.get_version().await?;
let latest  = client.get_latest_blockhash(None).await?;

Address-taking methods (e.g. get_balance, get_account_info) take any impl CheckAddress such as &Address:

use solana_address::address;

let owner = address!("11111111111111111111111111111111");
let balance = client.get_balance(&owner, None).await?.value;

See src/methods.rs for the full list of RPC methods.

Response size limit

HTTP responses are capped at 10 MiB by default so a misconfigured or malicious RPC can't OOM the wasm runtime with a multi-gigabyte body. Tune the limit with .with_max_response_size(bytes):

// 50 MiB for `getProgramAccounts` on a busy program:
let client = WasmClient::new("https://rpc.example.com")
    .with_max_response_size(50 * 1024 * 1024);

Oversized responses are rejected with RpcError::RpcRequestError("response body too large …") — pre-flight via Content-Length, or post-read for chunked encoding.

WebSocket / PubSub usage

Requires the pubsub feature.

use {futures::StreamExt, spume::WasmPubsubClient};

let client = WasmPubsubClient::connect("wss://api.mainnet-beta.solana.com")?;

// Stream of typed notifications:
let mut sub = client.slot_subscribe().await?;
while let Some(info) = sub.next().await {
    let info = info?;          // SlotInfo { slot, parent, root }
    // …
}

// Explicit unsubscribe awaits the server's ack; dropping the subscription
// fires a best-effort unsubscribe instead.
sub.unsubscribe().await?;

Supported subscriptions: account, block, logs, program, root, signature, slot, slotsUpdates, vote. See src/pubsub_methods.rs.

Example

examples/leptos-slot-monitor is a small Leptos CSR app that streams the live devnet slot via WebSocket and fetches the node version via HTTP:

cd examples/leptos-slot-monitor
cargo install trunk
trunk serve --open

Development

just fmt      # nightly rustfmt
just clippy   # clippy on the native target
just test     # spawn surfpool, run wasm integration tests, tear down

The test recipe expects surfpool, wasm-bindgen-cli@0.2.121, just, and Node 22+ in PATH. The repo's rust-toolchain.toml auto-installs the stable toolchain with the wasm32-unknown-unknown target.

CI runs fmt, clippy (on both --all-features and --no-default-features), and the wasm test suite on every push; see .github/workflows/ci.yml.