Introduction

flow-trades is a self-hosted Solana swap API. One Rust binary: it discovers pools, prices them with each venue's own arithmetic, and returns unsigned transactions that settle through the on-chain flow-router. It never holds keys or funds.

• GET /quote — best route and expected output
• POST /swap — unsigned transaction (v0 or v1) for the user to sign
• WS /swap-stream — every confirmed DEX swap, with prices

Source: flow-trades-solana (server) and flow-router-solana (on-chain router). Both MIT.

Quick Start

git clone https://github.com/sigint-zero/flow-trades-solana.git
cd flow-trades-solana
cargo build --release

# config.toml
rpc_url = "https://your-solana-rpc.com"
[streaming]
geyser_endpoint = "http://your-geyser-node:10000"   # optional

./target/release/flow-trades
curl "http://localhost:8080/quote?input=So11111111111111111111111111111111111111112&output=EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v&amount=1000000000"

Without a Geyser endpoint the server streams blocks over RPC blockSubscribe; same features, slightly higher latency.

Configuration

Priority: CLI flags > env vars > config.toml > defaults.

Requirements

• Solana RPC endpoint
• Yellowstone Geyser gRPC endpoint, optional
• 1 GB RAM recommended; Rust toolchain to build

API Reference

GET /quote

{
  "input_token": "So111…", "output_token": "EPjFW…",
  "amount_in": "1000000000", "amount_out": "162340000", "minimum_out": "161528300",
  "slippage_bps": 50, "price_impact": "0.12",
  "routes": [ { "pool": { "pool_address": "…", "dex": "Orca", "amount_in": "1000000000", "amount_out": "162340000", "fee": "40000" }, "percent": 100 } ],
  "platform_fee": { "amount": "0", "fee_bps": 0, "fee_token": "EPjFW…", "side": "output" },
  "quote_time_ms": 0.05
}

amount_out is the DEX output before the router fee. On multi-hop routes each later hop is quoted on the previous hop's guaranteed output, so the quote is what the route delivers.

POST /swap

{ "transaction": "base64…", "tx_version": 0, "block_height": 412875100, "compute_limit": 400000, "priority_fee": 5000 }

Sign the transaction with the wallet and submit it with sendTransaction.

GET /health

{ "status": "ok", "poolCacheSize": 2352, "registrySize": 25031, "streamUpdates": 2919, "streamErrors": 0,
  "blockhashCacheAgeMs": 398, "lastStreamUpdateMs": 65,
  "router": { "programId": "…", "feeBps": 0, "layout": "TransferChecked" } }

GET /metrics

Prometheus format: quotes served, stream updates and errors, cache, registry and database sizes.

WS /quote-ws

{ "input_mint": "So111…", "output_mint": "EPjFW…", "amount": 1000000000, "slippage_bps": 50, "interval_ms": 1000 }

Server pushes a full quote at the interval (minimum 100 ms).

WS /swap-stream

Every confirmed DEX swap parsed from blocks, with native and USD prices. Optional first frame:

{ "type": "subscribe", "filter": { "dex": ["PumpFun AMM"], "mint": "…", "pool": "…", "min_amount_usd": 10.0 } }

{ "type": "swap", "signature": "…", "slot": 412341234, "dex": "PumpFun AMM", "pool": "…", "user": "…",
  "input":  { "mint": "So111…", "amount": "1000000", "decimals": 9, "ui_amount": "0.001" },
  "output": { "mint": "…", "amount": "24637903819", "decimals": 6, "ui_amount": "24637.9" },
  "price_native": "24637903.82", "price_usd": "0.00000647", "amount_usd": "0.16" }

Frames: subscribed once, swap, ping every 30 s, lagged when a slow consumer drops messages. USDC, USDT and PYUSD count as $1; SOL comes from a built-in oracle; other pairs have null USD fields.

Fee Structure

The server reads the fee from the router named by ROUTER_PROGRAM_ID and reports it in every quote's platform_fee.

On-Chain Router

Source: flow-router-solana. One instruction runs 1–5 DEX legs as CPIs, checks the final output against min_amount_out, and collects the fee with TransferChecked if one is configured.

Integrators

If the router charges a fee, a whitelisted integrator wallet receives referral_split_bps of it. Set referral_account to that wallet; the admin whitelists it with add_integrator.

Supported DEXes

Performance

Error Codes

Security

• The server never holds keys; /swap returns unsigned transactions
• Router: no panics, typed errors; write-once config; token program, output mint and fee-account owner validated; one slippage check on the final output
• First-generation router audited by SigIntZero; second generation tested natively against SPL Token and Token-2022

Source Code

• github.com/sigint-zero/flow-trades-solana — server. cargo build --release, cargo test --lib
• github.com/sigint-zero/flow-router-solana — router. cargo test, cargo build-sbf