This example consumes PumpSwap events through solana-streamer-sdk and builds one follow-up buy from the event's post-trade reserves and dynamic fee rates. The trading client and blockhash cache are initialized before subscription, so the event hot path does not synchronously fetch a blockhash.

Run

cp .env.example .env
# Edit .env, then load it into the current shell:
set -a; source .env; set +a
export PRIVATE_KEY=your_base58_private_key
export RPC_URL=https://your-rpc.example
cargo run --release --package pumpswap_trading

GRPC_ENDPOINT and GRPC_AUTH_TOKEN are optional. TARGET_MINT or TARGET_POOL is required; when both are set, both must match. MAX_EVENT_AGE_MS defaults to 1000. The binary reads environment variables but does not load .env itself, so source the file first when using it.

Trade semantics

The buy uses BuyAmount::WithMaxInput, which applies slippage to maximum quote cost and is appropriate when fill priority matters.
Buy parameters use post-trade reserves and LP/protocol/creator fee bps from the event.
The event's raw and virtual quote reserves come from the same transaction snapshot. The hot path does not fetch the Pool account, avoiding both added latency and mixed-slot quotes.
The first matching event asynchronously records the pre-buy balance; the next fresh event performs the trade without a balance RPC in the submission hot path. It sells only the confirmed balance increase and refreshes pool state and blockhash before selling.
Use BuyAmount::ExactInput when the quote spend must be exact. That mode protects minimum output and can fail more often in an active pool.
If baseline warmup fails, the example waits for another event. Once transaction execution starts, an error keeps the one-shot guard locked because submission or position state may be uncertain; inspect the signatures and account state before retrying.

Production bots should also add durable signature deduplication, a position state machine, SWQoS configuration, and bounded requoting. Do not solve slippage errors by setting min_out to zero.