Exchange Integration

Pennysia sends the same quote request to every connected exchange. The best rate is selected. Integration is free. There are no listing fees.

Pennysia is not a competing exchange. It is the marketplace layer: venues integrate once, use a shared interface, and reach traders without building separate distribution. This reduces the barrier for new exchanges to compete.

Pennysia provides the frontend, wallet flow, and user experience. Partners provide a quote API and execution calldata.

Contact us to start onboarding. See Fees for how Pennysia earns.

Requirements

Item	Detail
Quote API	Sell/buy token, amount, chain → output, gas, calldata
Calldata	Settlement (or user for hard intents) is caller/receiver
Same-chain	SYNC routes settle on Ethereum in one tx
API key	Optional, for rate limits

Route types

SYNC (default)

Same-transaction swap through Settlement. Calldata must work when Settlement is msg.sender and buy tokens land on Settlement.

venue            = quote.tx.to
allowanceTarget  = quote.spender
callData         = quote.tx.data
value            = quote.tx.value
quotedReturn     = expected output

Reject: bridges, cross-chain hops, gasless relayer pulls, intent-only APIs.

Hard intents

CoW Protocol, UniswapX, Velora Delta. User signs off-chain; solver fills. Settlement not involved.

SODAX

Cross-chain intents. Settlement opens on Ethereum; fill is async on the hub chain. Contact Pennysia for onboarding.

Deposit-address

Walletless lanes such as InstaSwap, RocketX CEX, and RocketX Private. The user transfers sell tokens to an ephemeral deposit address; fill is async off Settlement. Quote APIs return estimated output and deposit metadata rather than Settlement calldata. Contact Pennysia for onboarding.

Quote response

{
  "sellToken": "0x...",
  "buyToken": "0x...",
  "sellAmount": "1000000000000000000",
  "buyAmount": "3500000000",
  "gasEstimate": "150000",
  "tx": { "to": "0x...", "data": "0x...", "value": "0" },
  "spender": "0x..."
}

Normalized into NormalizedQuote via backend SDK adapters.

Testing checklist

1. Quote output matches on-chain execution
2. Calldata works when Settlement calls the venue
3. Buy tokens arrive on Settlement, not the user
4. Spender matches approval target
5. Failed routes do not block fallback routes
6. Gas estimate is reasonable
7. API handles parallel fanout volume

Onboarding

1. Contact us with exchange name and API docs
2. Pennysia builds an adapter in src/aggregators/
3. Test on mainnet fork and staging
4. Exchange added to LAUNCH_SOURCES in backend SDK
5. Live in quote fanout and source list

Each exchange gets a canonical ID (e.g. kyberswap, zerox). Token support tracked in @pennysia/token-list.

SDKs

• Backend SDK: implement LiquidityAdapter
• Contracts SDK: build Settlement routes
• Settlement: on-chain execution

Questions: dev@pennysia.com

Webapp architecture

Reference app: webapp-interface.

User → POST /api/quotes/fanout → rank quotes → rebuild route → lane dispatch → wallet sign → execute

Lane	Routes
Settlement SYNC	DEX/aggregator via executeSwap
SODAX	Cross-chain intents
Hard intents	CoW, UniswapX, Velora Delta
Deposit-address	InstaSwap / RocketX CEX / RocketX Private deposit → operator fill

Package	Role
@pennysia/backend-sdk	Fanout, ranking, source manifest
@pennysia/contracts-sdk	Settlement routes and execution
@pennysia/token-list	Token fallback

Policies: Ethereum Mainnet only · Settlement address from contracts-sdk · Auto Fallback packs SYNC routes · API keys server-side only

Integrators implement LiquidityAdapter and register in the source manifest.

Related: Developer Guide · Swap Guide route types