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POST
/
otc
/
pop
Upload Proof of Payment
curl --request POST \
  --url https://api.linkio.world/otc/pop \
  --header 'Content-Type: multipart/form-data' \
  --header 'ngnc-sec-key: <api-key>' \
  --form reference=link-otc-12345678 \
  --form file='@example-file' \
  --form transaction_hash=0xabc123...
{
  "message": "<string>",
  "data": {
    "reference": "link-otc-12345678",
    "filename": "receipt.pdf",
    "transaction_hash": "<string>",
    "status": "processing"
  }
}

Authorizations

​
ngnc-sec-key
string
header
default:""
required

Body

multipart/form-data
​
reference
string
required

The transaction reference returned when the transaction was created (e.g. link-otc-12345678).

Example:

"link-otc-12345678"

​
transaction_type
enum<string>
required

The type of transaction. Determines which proof is expected — file for onramp, transaction_hash for offramp.

Available options:
onramp,
offramp
​
file
file

Required for onramp only. Proof of payment file. Accepted types: JPEG, PNG, GIF, PDF. Maximum size: 3 MB.

​
transaction_hash
string

Required for offramp only. The blockchain transaction hash or block explorer URL confirming stablecoin transfer (e.g. a Tronscan or Etherscan link).

Example:

"0xabc123..."

Response

Proof of payment submitted successfully.

​
message
string
​
data
object