Server Configuration

Reference for all Fynd server flags, worker pool tuning, blacklisting, logging, and monitoring.

Run options

All on-chain protocols are fetched from Tycho RPC by default, so --protocols is optional. The --tycho-url also defaults to the Fynd endpoint for the selected chain.

cargo run --release -- serve

To run on a different chain:

cargo run --release -- serve --chain base

--rpc-url defaults to the public endpoint https://eth.llamarpc.com. For production, use a dedicated endpoint:

cargo run --release -- serve \
  --rpc-url https://your-rpc-provider.com/v1/your_key

Specify protocols explicitly:

cargo run --release -- serve \
  --protocols uniswap_v2,uniswap_v3,vm:curve

See the full list of available protocols.

Including RFQ Protocols

Include RFQ (Request-for-Quote) protocols alongside on-chain protocols. Use the all_onchain keyword to combine auto-fetched on-chain protocols with specific RFQ protocols:

cargo run --release -- serve \
  --protocols all_onchain,rfq:bebop

Or specify both on-chain and RFQ protocols explicitly:

cargo run --release -- serve \
  --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.

Flag reference

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

Required

Flag	Env Var	Description
--tycho-api-key	TYCHO_API_KEY	Tycho API key

Optional

Flag	Env Var	Default	Description
--rpc-url	RPC_URL	https://eth.llamarpc.com	Ethereum RPC endpoint. Use a dedicated endpoint in production.
--tycho-url	TYCHO_URL	(chain-specific)	Tycho URL. Defaults to the Fynd endpoint for the selected chain (e.g. tycho-fynd-ethereum.propellerheads.xyz).
--chain	—	Ethereum	Target chain
-p, --protocols	—	(all on-chain)	Protocols to index (comma-separated). If omitted, all on-chain protocols are fetched from Tycho RPC. Use all_onchain to combine auto-fetched protocols with explicit entries (e.g. all_onchain,rfq:bebop).
--http-host	HTTP_HOST	0.0.0.0	HTTP bind address
--http-port	HTTP_PORT	3000	API port
--min-tvl	—	10.0	Minimum pool TVL in native token (ETH)
--tvl-buffer-ratio	—	1.1	Hysteresis buffer for TVL filtering. Components are added when TVL >= min_tvl and removed when TVL drops below min_tvl / tvl_buffer_ratio.
--traded-n-days-ago	—	3	Only include tokens traded within this many days.
--worker-router-timeout-ms	—	100	Default solve timeout (ms)
--worker-router-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
--gas-price-stale-threshold-secs	—	(disabled)	Health returns 503 when gas price exceeds this age. Disabled by default.

Worker pools (worker_pools.toml)

Worker pools control solver thread count and routing strategies. The default config ships with three 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
max_routes = 50

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

[pools.bellman_ford_5_hops]
algorithm = "bellman_ford"
num_workers = 3
task_queue_capacity = 1000
max_hops = 5
timeout_ms = 500

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

Worker pool fields

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
max_routes	(no limit)	Maximum number of candidate routes to evaluate per order

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 -- serve -w my_worker_pools.toml

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",
]

Logging and monitoring

Logs

Control log verbosity with RUST_LOG:

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

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

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

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

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.