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POST
/
accounts
/
{account_id}
/
plan
/
swap
Plan Swap
curl --request POST \
  --url https://api.example.com/accounts/{account_id}/plan/swap

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Plan Swap

Creates a plan to swap one asset for another via DEX aggregation. Legend fetches the best available quote and returns a plan with the swap details. Returns a plan ID and an EIP-712 digest that must be signed to authorize execution.

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Request

POST /accounts/:account_id/plan/swap

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Path parameters

ParameterTypeDescription
account_idstringThe sub-account ID

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Body parameters

ParameterTypeRequiredDescription
sell_assetstringYesAsset to sell (e.g., "USDC")
buy_assetstringYesAsset to buy (e.g., "WETH")
networkstringYesTarget network (e.g., "base", "mainnet"). Funds on other chains are bridged automatically.
sell_amountstringOne ofAmount to sell in the asset’s smallest unit
buy_amountstringOne ofAmount to buy in the asset’s smallest unit
Exactly one of sell_amount or buy_amount must be provided.

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Examples

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Sell exact amount

curl -X POST https://prime-api.legend.xyz/accounts/acc_2o0yiljtp378/plan/swap \
  -H "Authorization: Bearer $LEGEND_QUERY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sell_asset": "USDC",
    "buy_asset": "WETH",
    "network": "base",
    "sell_amount": "10000000"
  }'

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Buy exact amount

curl -X POST https://prime-api.legend.xyz/accounts/acc_2o0yiljtp378/plan/swap \
  -H "Authorization: Bearer $LEGEND_QUERY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "sell_asset": "USDC",
    "buy_asset": "WETH",
    "network": "base",
    "buy_amount": "1000000000000000000"
  }'
Response (201 Created)
{
  "plan_id": "pln_71mcui082png",
  "details": {
    "quark_operation_actions": [...],
    "eip712_data": {
      "digest": "0x8a3f...b7c2",
      "domain_separator": "0x...",
      "hash_struct": "0x..."
    }
  },
  "expires_at": "2025-06-15T10:32:00Z"
}

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Response fields

FieldTypeDescription
plan_idstringUnique identifier for this plan (pln_ prefix)
detailsobjectTransaction details including EIP-712 signing data
details.eip712_data.digeststringThe hash to sign with the account’s signer key
expires_atstringISO 8601 timestamp — plan must be executed before this time

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Errors

StatusCodeDescription
400invalid_paramsMissing required parameters or both sell_amount and buy_amount provided
400plan_failedCould not generate a valid plan (e.g., insufficient balance)
400no_walletAccount has no wallets
408timeoutFolio computation timed out
422swap_quote_failedCould not fetch a swap quote from the DEX aggregator

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Notes

  • Plans expire after 2 minutes. Sign and execute via Execute Plan before expiry.
  • Provide exactly one of sell_amount or buy_amount. If sell_amount is given, the API finds the best quote for selling that exact amount. If buy_amount is given, it finds a quote to buy that exact amount.
  • A 0.15% Legend fee is applied to the buy side of the quote.