Quickstart

Run Fynd

Get Fynd running locally. This guide covers building, running, and tuning the solver. No code changes required.

Prerequisites

• Rust 1.92+ (install via rustup)

• A Tycho API key (get one here)

• An Ethereum RPC endpoint for the target chain

1. Build

git clone https://github.com/propeller-heads/fynd.git
cd fynd
cargo build --release

The release binary will be at target/release/fynd.

2. Set Environment Variables

export TYCHO_API_KEY=your-api-key
export RPC_URL=https://eth.llamarpc.com
export RUST_LOG=info

3. Run

cargo run --release -- \
  --tycho-url tycho-beta.propellerheads.xyz \
  --protocols uniswap_v2,uniswap_v3,uniswap_v3,vm:curve \
  --min-tvl 50 

See the full list of available protocols.

Once running, Fynd:

1. Connects to Tycho's Streams and syncs all protocol states

2. Builds routing graphs and computes derived data (spot prices, pool depths and token gas prices)

3. Starts the HTTP API on http://localhost:3000

Wait for the /v1/health endpoint to return healthy before sending orders.

3.1 Including RFQ Protocols

Include RFQ (Request-for-Quote) protocols alongside on-chain protocols:

cargo run --release -- \
  --tycho-url tycho-beta.propellerheads.xyz \
  --rpc-url $RPC_URL \
  --protocols uniswap_v2,uniswap_v3,rfq:bebop

Limitations:

• RFQ protocols cannot run alone. At least one on-chain protocol is required.

Environment variables:

• RFQ protocols require API keys passed via environment variables. Check the RFQ protocol docs for the specific variables each protocol needs.

3.2 Check Solver Health

curl http://localhost:3000/v1/health

Returns "healthy":true when ready to receive requests.

4. Submit a solve request

Get the quote for 1 WETH -> USDC (or any pair/amount you want):

curl -X POST http://localhost:3000/v1/solve \
  -H "Content-Type: application/json" \
  -d '{
    "orders": [
      {
        "token_in": "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
        "token_out": "0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48",
        "amount": "1000000000000000000",
        "side": "sell",
        "sender": "0x0000000000000000000000000000000000000001"
      }
    ],
    "options": {
      "timeout_ms": 5000,
      "min_responses": 1
    }
  }'

The response includes the optimal route, amounts, gas estimates, and the net output after gas costs.

4.1 - Optional request fields

Field	Description
options.timeout_ms	Overrides the default solve timeout (configured via global config see configuration section).
options.min_responses	Return early after N solver pools respond. If set to null - it will wait for all solver pools respond until timeout.
options.max_gas	Discard routes above this gas limit

Full interface details: API Specifications

5. Configuration

Tune Fynd with the following flags:

Required

Flag	Env Var	Description
--rpc-url	RPC_URL	Ethereum RPC endpoint
--tycho-api-key	TYCHO_API_KEY	Tycho API key

Optional

Flag	Env Var	Default	Description
--tycho-url	TYCHO_URL	localhost:4242	Tycho WebSocket URL
--chain	--	Ethereum	Target chain
-p, --protocols	--	(all)	Protocols to index (comma-separated)
--http-port	HTTP_PORT	3000	API port
--min-tvl	--	10.0	Minimum pool TVL in native token (ETH)
--tvl-buffer-multiplier	--	1.1	Hysteresis buffer for TVL filtering
--order-manager-timeout-ms	--	100	Default solve timeout (ms)
--order-manager-min-responses	--	0	Early return threshold (0 = wait for all pools)
-w, --worker-pools-config	WORKER_POOLS_CONFIG	worker_pools.toml	Worker pools config file path
--blacklist-config	BLACKLIST_CONFIG	blacklist.toml	Blacklist config file path
--disable-tls	--	false	Disable TLS for Tycho connection
--min-token-quality	--	100	Minimum token quality filter
--gas-refresh-interval-secs	--	30	Gas price refresh interval
--reconnect-delay-secs	--	5	Reconnect delay on connection failure

Run cargo run --release -- --help for the full list.

5.1 - Worker pools file (worker_pools.toml)

Worker pools control solver thread count and routing strategies. The default config ships with two pools:

# worker_pools.toml
[pools.most_liquid_2_hops_fast]
algorithm = "most_liquid"
num_workers = 5
task_queue_capacity = 1000
max_hops = 2
timeout_ms = 100

[pools.most_liquid_3_hops]
algorithm = "most_liquid"
num_workers = 3
task_queue_capacity = 1000
min_hops = 2
max_hops = 3
timeout_ms = 5000

Both pools solve every incoming order in parallel. Fynd picks the best result across pools within the timeout.

Worker Pool Configuration:

Field	Default	Description
algorithm	"most_liquid"	Algorithm used for the pool
num_workers	CPU count	Number of OS threads dedicated to this pool
task_queue_capacity	1000	Maximum number of orders that can be queued simultaneously
min_hops	1	Minimum number of hops required for routing
max_hops	3	Maximum number of hops permitted for routing
timeout_ms	100	Maximum time in milliseconds allowed per order processing in this pool

Tuning tips:

• More workers = more orders can be solved concurrently. Each worker is a dedicated OS thread, so avoid exceeding your CPU core count across all pools.

• Lower max_hops = faster solves but may miss better multi-hop routes.

• Higher max_hops = explores deeper routes but takes longer. Pair with a higher timeout_ms.

• The "fast + deep" pattern (default config) gives quick responses from the 2-hop pool while the 3-hop pool searches for better routes in the background.

To use a custom config file:

cargo run --release -- \
  --tycho-url tycho-beta.propellerheads.xyz \
  --rpc-url $RPC_URL \
  -w my_worker_pools.toml

5.1 Blacklist (blacklist.toml)

Exclude specific components from routing, useful for components with known simulation issues (e.g., rebasing tokens on UniswapV3 pools):

[blacklist]
components = [
    "0x86d257cdb7bc9c0df10e84c8709697f92770b335",
]

6. Logging and Monitoring

Logs

Control log verbosity with RUST_LOG:

# Minimal output
RUST_LOG=warn cargo run --release -- ...

# Default (recommended)
RUST_LOG=info cargo run --release -- ...

# Debug solver internals
RUST_LOG=info,tycho_solver=debug cargo run --release -- ...

# Trace-level (very verbose, not recommended)
RUST_LOG=info,tycho_solver=trace cargo run --release -- ...

Prometheus Metrics

Metrics are exposed at http://localhost:9898/metrics (always on). Scrape this endpoint with Prometheus or any compatible tool. Available metrics: solve duration, response counts, failure types, and pool performance.

7. Validating and Executing the Solutions

The repository includes an end-to-end example at examples/quickstart/ that demonstrates quoting, simulating, and executing swaps against a running solver. See Executing the solutions for the full walkthrough.