curl --request POST \
  --url https://propamm.kipseli.win/v2/swap/sign \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --data '
{
  "tokenIn": "0x4200000000000000000000000000000000000006",
  "tokenOut": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "fee": "3000",
  "userAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
}
'

{
  "verificationData": "0xabcdef...",
  "timestamp": 1741737600
}

API Reference

Request Swap Verification

ABI-encodes (tokenIn, tokenOut, timestamp, fee, originRate, userAddress), Keccak256-hashes the payload, and signs it with secp256k1. The recovery ID is adjusted from [0,1] to [27,28] per the Ethereum Yellow Paper.

The response contains ABI-encoded verification data (fee, originRate, userAddress, signature) ready for on-chain submission.

Use the chainId body field to select the chain the swap will be executed on; the token pair must be supported there. Omitting it (or passing 0) targets the default chain, Base (8453).

Note that the signed payload itself does not include the chain id — chainId selects which chain’s pair list and signing key are used.

POST

swap

sign

curl --request POST \
  --url https://propamm.kipseli.win/v2/swap/sign \
  --header 'Content-Type: application/json' \
  --header 'X-API-KEY: <api-key>' \
  --data '
{
  "tokenIn": "0x4200000000000000000000000000000000000006",
  "tokenOut": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "fee": "3000",
  "userAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
}
'

{
  "verificationData": "0xabcdef...",
  "timestamp": 1741737600
}

Before executing a swap on-chain, call this endpoint to obtain verificationData and timestamp. Both values must be passed directly into the swap() function — if either is modified or expired, the transaction will revert. Optionally, pass amountIn (and minAmountOut) to receive pre-built calldata ready for direct submission.

Selecting a Chain

Pass the target chain in the request body with chainId:

Chain	`chainId`	Router (PropAmm)	Quote token
BNB Chain	`56`	`0x4cb2140C29518db6203f661B9F6dD60B68BB7f0d`	USDT
Base	`8453`	`0x71C2Ed90CC288229Be59F26b8B3EEF3C07d7ab99`	USDC
Robinhood Chain	`4663`	`0x4f1ce663bF2E5e3b4A4ba88F6D1BF227e5597402`	USDG

Every pair is base token / quote token, so the stablecoin leg of your tokenIn/tokenOut must be that chain’s quote token — USDT on BNB Chain, not USDC. See Get Orderbook for addresses.

If chainId is omitted (or 0), the request targets Base (8453). chainId selects which chain’s pair list is validated against and which signing key is used — the token pair must be supported on that chain, or the request fails with 400 PAIR_NOT_FOUND. An unsupported chain returns 400 UNSUPPORTED_CHAIN.

Swap Execution Flow

Step 1 — Call this endpoint

Minimal (verification data only):

curl -X POST https://propamm.kipseli.win/v2/swap/sign \
  -H "Content-Type: application/json" \
  -H "X-API-KEY: $KIPSELI_API_KEY" \
  -d '{
    "chainId":     8453,
    "tokenIn":     "0x4200000000000000000000000000000000000006",
    "tokenOut":    "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "fee":         "30",
    "userAddress": "0x1111111111111111111111111111111111111111"
  }'

Response:

{
  "verificationData": "0x...",
  "timestamp": 1741737600
}

With calldata (pass amountIn and optionally minAmountOut):

curl -X POST https://propamm.kipseli.win/v2/swap/sign \
  -H "Content-Type: application/json" \
  -H "X-API-KEY: $KIPSELI_API_KEY" \
  -d '{
    "chainId":      8453,
    "tokenIn":      "0x4200000000000000000000000000000000000006",
    "tokenOut":     "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "fee":          "30",
    "userAddress":  "0x1111111111111111111111111111111111111111",
    "amountIn":     "1000000000000000000",
    "minAmountOut": "3150000000"
  }'

Response:

{
  "verificationData": "0x...",
  "timestamp": 1741737600,
  "calldata": "0x..."
}

The calldata field is ABI-encoded for swap(address,uint256,address,uint256,uint256,bytes) and can be submitted directly to the router without further encoding.

Step 2 — Approve the Router

Use the Router for the chain you passed as chainId (see Selecting a Chain). The example below is Base.

IERC20(tokenIn).approve(
    0x71C2Ed90CC288229Be59F26b8B3EEF3C07d7ab99, // Router on Base (8453)
    amountIn
);

Step 3 — Execute the swap on-chain

Option A — build the call yourself:

IPropAmm(0x71C2Ed90CC288229Be59F26b8B3EEF3C07d7ab99).swap( // Router on Base (8453)
    tokenIn,
    amountIn,
    tokenOut,
    minOutAmount,      // slippage protection — use quote() to calculate
    timestamp,         // from API response
    verificationData   // from API response
);

Parameter	Description
`tokenIn`	Input token address
`amountIn`	Amount of input token (in token decimals)
`tokenOut`	Output token address
`minOutAmount`	Minimum acceptable output — set this to protect against slippage
`timestamp`	Returned by this API — pass through unchanged
`verificationData`	Returned by this API — pass through unchanged

Option B — use the calldata from the API (requires amountIn in Step 1):

// Router on Base (8453)
(bool success, ) = address(0x71C2Ed90CC288229Be59F26b8B3EEF3C07d7ab99).call(calldata);
require(success, "swap failed");

The calldata is already ABI-encoded for swap(address,uint256,address,uint256,uint256,bytes) — no further encoding needed.

Request Fields

Field	Type	Required	Description
`chainId`	integer	No	Chain the swap will be executed on. Omitted or `0` targets `8453` (Base).
`tokenIn`	string	Yes	Input token address on `chainId`
`tokenOut`	string	Yes	Output token address on `chainId`
`fee`	string	Yes	Fee tier in 0.1 bps resolution — see Fee Parameter
`userAddress`	string	Yes	Address that will submit the swap
`amountIn`	string	No	Input amount in wei. When provided, the response includes `calldata`
`minAmountOut`	string	No	Minimum accepted output in wei. Only used with `amountIn`; defaults to `0`

Fee Parameter

The fee field uses 0.1 bps resolution:

Value	Rate
`1`	0.1 bps (0.001%)
`10`	1 bps (0.01%)
`30`	3 bps (0.03%)
`100`	10 bps (0.10%)

The fee is deducted from the output amount (amountOut) and settled monthly in a mutually agreed currency.

Authorizations

X-API-KEY

string

header

required

API key issued by the Kipseli team. Required on every request. Authorization: Bearer <key> is accepted as an alternative.

Body

application/json

tokenIn

string

required

EVM hex address of the input token (checksummed or lowercase)

Example:

"0x4200000000000000000000000000000000000006"

tokenOut

string

required

EVM hex address of the output token (checksummed or lowercase)

Example:

"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"

fee

string

required

Fee tier as a decimal string in 0.1 bps resolution(e.g. "3000" = 3%)

Example:

"3000"

userAddress

string

required

EVM hex address of the user submitting the swap

Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

chainId

integer<int64>

default:8453

Chain the swap will be executed on. Supported values: 56 (BNB Chain), 8453 (Base), 4663 (Robinhood Chain). Omit it (or pass 0) for the default chain, Base (8453).

It selects the pair list validated against and the signing key used. A chain the service does not serve returns 400 UNSUPPORTED_CHAIN; a pair not tracked on it returns 400 PAIR_NOT_FOUND.

Required range: x >= 0

Example:

8453

amountIn

string

Input token amount in wei as a decimal string. When provided, the response will include a calldata field with ABI-encoded calldata for the swap function.

Example:

"1000000000000000000"

minAmountOut

string

Minimum accepted output token amount in wei as a decimal string. Only used when amountIn is provided. Defaults to 0 if omitted.

Example:

"3150000000"

Response

Quote signed successfully

verificationData

string

ABI-encoded hex string (with 0x prefix) containing (fee, originRate, userAddress, signature). Pass this directly to the on-chain verification contract.

Example:

"0xabcdef..."

timestamp

integer<int64>

Unix timestamp (seconds) at which the signature was generated

Example:

1741737600

calldata

string

ABI-encoded calldata (with 0x prefix) for the swap(address,uint256,address,uint256,uint256,bytes) function. Only present when amountIn was provided in the request. The encoded arguments are (tokenIn, amountIn, tokenOut, minAmountOut, quoteTimestamp, verificationData).

Example:

"0x..."

​Selecting a Chain

​Swap Execution Flow

​Step 1 — Call this endpoint

​Step 2 — Approve the Router

​Step 3 — Execute the swap on-chain

​Request Fields

​Fee Parameter

Authorizations

Body

Response

Selecting a Chain

Swap Execution Flow

Step 1 — Call this endpoint

Step 2 — Approve the Router

Step 3 — Execute the swap on-chain

Request Fields

Fee Parameter