Bound Lending

Sign bound lending/option PSBT (origination, repayment, option_origination, option_exercise) and broadcast

post

Body

application/json

psbtBase64stringRequired

Base64-encoded PSBT with all required signatures except RadFi BE trading wallet co-sign

Example: cHNidP8BAH0CAAAA...

typestring · enumRequired

PSBT type: origination, repayment, option_origination, or option_exercise

Example: originationPossible values:

userTradingAddressstringOptional

Trading wallet address of the user who initiates from the FE (borrower for lending, seller for options)

Example: tb1p...

solverTradingAddressstringOptional

Trading wallet address of the solver/counterparty (lender for lending, buyer for options)

Example: tb1p...

borrowerPubkeystringOptional

Borrower 33-byte compressed pubkey hex (required for origination/repayment)

lenderPubkeystringOptional

Lender 33-byte compressed pubkey hex (required for origination/repayment)

forfeitureExpiryTimestampnumberOptional

Absolute Unix timestamp for forfeiture CLTV leaf (required for origination/repayment)

previousLenderPubkeystringOptional

Lender 33-byte compressed pubkey hex of the previous loan escrow being rolled over. Required only when the origination PSBT spends a previous escrow input (rollover).

previousForfeitureExpiryTimestampnumberOptional

Forfeiture CLTV expiry timestamp of the previous loan escrow being rolled over. When set, the origination PSBT is treated as a rollover: input 0 must spend the reconstructed previous escrow (script-path) and the metadata OP_RETURN flag must be 0x04.

previousLenderTradingAddressstringOptional

Previous lender trading wallet address (used in cross-lender rollover to allow the payment output back to the previous lender).

Example: tb1p...

sellerPubkeystringOptional

Seller 33-byte compressed pubkey hex (required for option_origination/option_exercise)

escrowExpiryTimestampnumberOptional

Absolute Unix timestamp for escrow CLTV expiry (required for option_origination/option_exercise)

hashYstringOptional

SHA256 hash Y (32-byte hex) for HTLC escrow (required for option_origination/option_exercise)

Responses

200Success

application/json

txIdstringRequired

Transaction ID of the broadcasted transaction

hexstringRequired

Raw transaction hex

post

/api/bound-lending/transaction/sign

HTTPcURLJavaScriptPython

POST /api/bound-lending/transaction/sign HTTP/1.1
Host: api.radfi.co
Content-Type: application/json
Accept: */*
Content-Length: 369

{
  "psbtBase64": "cHNidP8BAH0CAAAA...",
  "type": "origination",
  "userTradingAddress": "tb1p...",
  "solverTradingAddress": "tb1p...",
  "borrowerPubkey": "text",
  "lenderPubkey": "text",
  "forfeitureExpiryTimestamp": 1,
  "previousLenderPubkey": "text",
  "previousForfeitureExpiryTimestamp": 1,
  "previousLenderTradingAddress": "tb1p...",
  "sellerPubkey": "text",
  "escrowExpiryTimestamp": 1,
  "hashY": "text"
}

200Success

{
  "txId": "text",
  "hex": "text"
}