The service exposes a single HTTP endpoint, with Axum for the web layer and the solana-client non-blocking API for all blockchain interactions.

• SlotCache asynchronous, size-limited cache to store confirmed slot numbers. The cache maintains a limit of the last 1000 confirmed slots and with a simple eviction policy removes the oldest entries when the capacity is exceeded. Used scc for high-performance concurrent data access.

• run_cache_poller minimizes RPC calls by querying the getBlocks range from the last known confirmed slot up to the current latest slot. This ensures the cache is continuously and efficiently hydrated with confirmed data.

• run_server Axum server exposes the primary endpoint: /isSlotConfirmed/{slot}.

  • Checks the local cache first (low-latency HIT). If a miss occurs, it falls back to a direct, single-slot getBlocks RPC query to provide the most up-to-date status before the poller catches up.
  • Returns 200 OK if the slot is confirmed, or 404 NOT FOUND if it is not a confirmed block.

cargo build

cargo test

The service requires the RUST_LOG environment variable to be set for visible tracing output. Use the command appropriate for your operating system's shell:

PowerShell : $env:RUST_LOG="info,metrics=info"; cargo run

Bash/Zsh (Linux/macOS) : RUST_LOG="info,metrics=info" cargo run

With the server running (listening on 0.0.0.0:3000), use a new terminal to query the endpoint.

PowerShell (Windows) : irm -Method Get http://localhost:3000/isSlotConfirmed/377335664

Bash/Zsh (Linux/macOS) : curl -i http://localhost:3000/isSlotConfirmed/377335664