Stablecoin payments — Solana USDC / USDT (Bitquery stream)#

This skill provides a real-time WebSocket subscription to Solana token transfers where the mint is USDT ( Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB) or USDC ( EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v), and Instruction.Program.Method excludes "swap" to cut DEX swap noise. Each event includes transfer amounts (and USD where available), parties, transaction metadata, and the instruction program method.

When to use this skill

• Stream USDC / USDT transfers on Solana in real time
• Build dashboards or alerts for stablecoin payment flow
• Audit sender, receiver, signature, and fees per transfer

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What to consider before installing#

This skill uses the Bitquery streaming API and one credential. Before installing:

1. Registry metadata: Ensure BITQUERY_API_KEY is declared for installers when publishing to a registry.
2. Token only via URL: Bitquery accepts the API token only in the WebSocket URL as ?token=.... The URL can leak via logs, shell history, or proxies. Do not print or log the full URL; store the key in an environment variable; rotate if exposed.
3. Sandbox first: Run in a virtualenv or container first to confirm behavior.
4. Schema drift: If the subscription fails validation, check Bitquery Solana docs and adjust the where clause only; keep the same mints and fields when possible.

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Security Checklist#

Before running this skill, confirm:

• BITQUERY_API_KEY is set: export BITQUERY_API_KEY=your_token_here
• You run in a sandboxed or isolated environment where feasible
• You will not print, log, or commit the full WebSocket URL
• You can rotate the key if it may have been exposed

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Prerequisites#

• Environment: BITQUERY_API_KEY (required).
• Runtime: Python 3.8+ and pip. Install: pip install 'gql[websockets]' (see requirements.txt).

URL-only auth: Construct the WebSocket URL from the env var and pass it only to the transport. Never emit the full URL in output or logs.

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Use cases#

1. Treasury / ops monitoring — Watch USDC/USDT in and out of known wallets in real time.
2. Large-transfer alerts — Filter on AmountInUSD or raw Amount in downstream code.
3. Reconciliation — Match Transaction.Signature and Block.Time to internal ledgers.
4. Program attribution — Use Instruction.Program.Method to see which program path initiated the transfer.

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Step 1 — Check API Key#

python

import os
api_key = os.getenv("BITQUERY_API_KEY")
if not api_key:
    print("ERROR: BITQUERY_API_KEY environment variable is not set.")
    print("Run: export BITQUERY_API_KEY=your_token")
    exit(1)

If the key is missing, tell the user and stop.

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Step 2 — Run the stream#

bash

pip install 'gql[websockets]'

bash

python ~/.openclaw/skills/stablecoin-payments/scripts/stream_stablecoin_payments.py

Optional timeout:

bash

python ~/.openclaw/skills/stablecoin-payments/scripts/stream_stablecoin_payments.py --timeout 60

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Inline subscription (Python)#

python

import asyncio, os
from gql import Client, gql
from gql.transport.websockets import WebsocketsTransport

async def main():
    token = os.environ["BITQUERY_API_KEY"]
    url = f"wss://streaming.bitquery.io/graphql?token={token}"
    transport = WebsocketsTransport(
        url=url,
        headers={"Sec-WebSocket-Protocol": "graphql-ws"},
    )
    async with Client(transport=transport) as session:
        sub = gql("""
            subscription {
              Solana {
                Transfers(
                  where: {
                    Transfer: {
                      Currency: {
                        MintAddress: {
                          in: [
                            "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
                            "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v"
                          ]
                        }
                      }
                    }
                    Instruction: {
                      Program: {
                        Method: { notIncludesCaseInsensitive: "swap" }
                      }
                    }
                  }
                ) {
                  Transfer {
                    Amount
                    AmountInUSD
                    Sender { Address Owner }
                    Receiver { Address Owner }
                    Currency { Symbol Name MintAddress }
                  }
                  Instruction { Program { Method } }
                  Block { Time Height Slot }
                  Transaction {
                    Signature
                    Signer
                    Fee
                    FeeInUSD
                    FeePayer
                  }
                }
              }
            }
        """)
        async for result in session.subscribe(sub):
            for row in (result.get("Solana") or {}).get("Transfers") or []:
                print(row)

asyncio.run(main())

---

Key fields#

AreaFieldsTransferAmount, AmountInUSD, Sender / Receiver ( Address, Owner), Currency ( Symbol, Name, MintAddress)InstructionProgram.Method (subscription filter: notIncludesCaseInsensitive: "swap")BlockTime, Height, SlotTransactionSignature, Signer, Fee, FeeInUSD, FeePayer

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Format output for users#

When summarizing a transfer, use a clear block like:

text

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Solana stablecoin transfer  @ 2025-03-25T14:00:00Z  Slot 123456789
USDC (EPjF...Dt1v)  Amount: 1,000.50  (~$1,000.50 USD)
From: SenderAddr...  (owner: ...)  →  To: ReceiverAddr...
Tx: 5xYz...abc  |  Fee: 0.000005 SOL  (~$0.00 USD)  |  Fee payer: ...
Program method: transfer / ...
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

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Error handling#

• Missing BITQUERY_API_KEY: Tell the user to export it and exit.
• WebSocket failed / 401: Invalid or expired token (auth is URL ?token= only).
• Subscription errors in payload: Stop cleanly; do not log the full URL.
• No events: Solana activity can be bursty; confirm token and network; wait for the next transfer.

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Reference#

Mint list, full subscription, and field notes: references/graphql-fields.md.