Blink

Blink Skill

Bitcoin Lightning wallet operations via the Blink API. Enables agents to check balances, receive payments via invoices, send payments over Lightning, swap between BTC and USD wallets, track transactions, and monitor prices.

What is Blink?

Blink is a custodial Bitcoin Lightning wallet with a GraphQL API. Key concepts:

• API Key — authentication token (format: blink_...) with scoped permissions (Read, Receive, Write)
• BTC Wallet — balance denominated in satoshis
• USD Wallet — balance denominated in cents (stablecoin pegged to USD)
• Lightning Invoice — BOLT-11 payment request string (lnbc...) used to receive payments
• Lightning Address — human-readable address (user@domain) for sending payments without an invoice
• LNURL — protocol for interacting with Lightning services via encoded URLs

Environment

• Requires bash and Node.js 18+.
• Requires BLINK_API_KEY environment variable with appropriate scopes.
• For WebSocket subscriptions: Node 22+ (native) or Node 20+ with --experimental-websocket.
• Zero runtime npm dependencies. Only Node.js built-in modules are used (node:util, node:fs, node:path, node:child_process).

Use this skill for concrete wallet operations, not generic Lightning theory.

Getting Started

1. Get your API key

1. Create a free account at dashboard.blink.sv.
2. Go to API Keys and create a key with the scopes you need.
3. Set it in your environment:

export BLINK_API_KEY="blink_..."

API Key Scopes:

• Read — query balances, transaction history, price, account info
• Receive — create invoices
• Write — send payments (use with caution)

Tip: Start with Read + Receive only. Add Write when you need to send payments.

2. Verify it works

node {baseDir}/scripts/balance.js

If you see JSON with your wallet balances, you're ready.

3. Staging / Testnet (recommended for first-time setup)

To use the Blink staging environment (signet) instead of real money:

export BLINK_API_URL="https://api.staging.blink.sv/graphql"

Create a staging API key at dashboard.staging.blink.sv. The staging environment uses signet bitcoin (no real value) — perfect for testing payment flows safely.

If BLINK_API_URL is not set, production (https://api.blink.sv/graphql) is used by default.

API key auto-detection

Scripts automatically resolve BLINK_API_KEY using this order:

1. process.env.BLINK_API_KEY (checked first)
2. Shell rc files: ~/.profile, ~/.bashrc, ~/.bash_profile, ~/.zshrc — scanned for an export BLINK_API_KEY=... line only

No source ~/.profile prefix is needed. The rc file scan uses a targeted regex that reads only the BLINK_API_KEY export line — no other data is extracted from these files.

Agent Safety Policy

These rules are mandatory for any AI agent using this skill:

1. Ask before spending. Never execute pay_invoice.js, pay_lnaddress.js, pay_lnurl.js, or swap_execute.js without explicit user confirmation of the amount and recipient.
2. Dry-run first. For swaps, always run with --dry-run before executing for real unless the user explicitly says to skip it.
3. Check balance before sending. Always run balance.js before any payment or swap to verify sufficient funds.
4. Probe fees before paying. Run fee_probe.js before pay_invoice.js to show the user the fee cost.
5. Use minimum scopes. Only request Write-scoped API keys when send operations are actually needed.
6. Never log or display the API key. Treat BLINK_API_KEY as a secret. Do not echo it, include it in messages, or write it to files.
7. Prefer staging for testing. When the user is testing or learning, suggest setting BLINK_API_URL to the staging endpoint.
8. Respect irreversibility. Warn the user that Lightning payments and swaps cannot be reversed once executed.

Bitcoin Units

• BTC wallet amounts are always in satoshis (sats). 1 BTC = 100,000,000 sats.
• USD wallet amounts are always in cents. $1.00 = 100 cents.
• When displaying amounts to users, use the formatted fields from output JSON (e.g. btcBalanceUsdFormatted, usdBalanceFormatted).
• Do not perform manual BTC-to-USD conversion math — use node {baseDir}/scripts/price.js <sats> or the btcBalanceUsd field from balance output instead.
• For swap amounts, the --unit flag controls interpretation: sats for BTC, cents for USD.

Workflow

1. Pick the operation path first:

• Receive payments (invoice creation, QR codes, payment monitoring).
• Send payments (invoice pay, Lightning Address, LNURL, BTC or USD wallet).
• Swap between wallets (BTC <-> USD internal conversion).
• Read-only queries (balance, transactions, price, account info).

2. Configure API access from blink-api-and-auth:

• Set BLINK_API_KEY with the correct scopes for your operation.
• Optionally set BLINK_API_URL for staging/testnet.
• Verify connectivity with balance.js.

3. For sending payments, follow payment-operations:

• Check balance before sending.
• Probe fees with fee_probe.js.
• Choose BTC or USD wallet with --wallet flag.
• Use --dry-run to preview without sending. Use --max-amount to cap outgoing amounts.
• Execute payment and verify in transaction history.

4. For swapping between wallets, follow swap-operations:

• Get a quote with swap_quote.js to preview the conversion.
• Execute with swap_execute.js (use --dry-run first).

5. For receiving payments, follow invoice-lifecycle:

• Create BTC or USD invoice.
• Parse two-phase output (invoice created, then payment resolution).
• Generate QR code and send to payer.
• Monitor via auto-subscribe, polling, or standalone subscription.

6. Apply safety constraints:

• Use minimum API key scopes for the task.
• Test on staging before production.
• Always check balance before sending.
• Use --dry-run on payment and swap commands to preview before executing.
• Use --max-amount <sats> to enforce a per-payment ceiling (pay_lnaddress, pay_lnurl).
• Use --force to override balance-check failures when you know the payment should proceed.
• Payments are irreversible once settled.

Quick Commands

# Check balances
node {baseDir}/scripts/balance.js

# Create BTC invoice (auto-subscribes to payment)
node {baseDir}/scripts/create_invoice.js 1000 "Payment for service"

# Pay a Lightning invoice
node {baseDir}/scripts/pay_invoice.js lnbc1000n1...

# Pay from USD wallet
node {baseDir}/scripts/pay_invoice.js lnbc1000n1... --wallet USD

# Get current BTC/USD price
node {baseDir}/scripts/price.js

# Quote BTC -> USD internal swap (dry-run)
node {baseDir}/scripts/swap_quote.js btc-to-usd 5000

# Execute USD -> BTC internal swap
node {baseDir}/scripts/swap_execute.js usd-to-btc 500 --unit cents

Core Commands

Check Wallet Balances

node {baseDir}/scripts/balance.js

Returns JSON with all wallet balances (BTC in sats, USD in cents), wallet IDs, pending incoming amounts, and a pre-computed USD estimate for the BTC wallet. Use btcBalanceUsd for the BTC wallet's USD value — do not calculate it yourself.

Create Lightning Invoice (BTC)

node {baseDir}/scripts/create_invoice.js <amount_sats> [--timeout <seconds>] [--no-subscribe] [memo...]

Generates a BOLT-11 Lightning invoice for the specified amount in satoshis. Returns the paymentRequest string that can be paid by any Lightning wallet. The BTC wallet ID is resolved automatically.

Auto-subscribe: After creating the invoice, the script automatically opens a WebSocket subscription and waits for payment. It outputs two JSON objects to stdout:

1. Immediately — {"event": "invoice_created", ...} with paymentRequest, paymentHash, etc.
2. When resolved — {"event": "subscription_result", "status": "PAID"|"EXPIRED"|"TIMEOUT", ...}

The agent should read the first JSON to share the invoice/QR with the user right away, then wait for the second JSON to confirm payment.

• amount_sats — amount in satoshis (required)
• --timeout <seconds> — subscription timeout (default: 300). Use 0 for no timeout.
• --no-subscribe — skip WebSocket auto-subscribe, just create the invoice and exit
• memo... — optional description attached to the invoice (remaining args joined)

Create Lightning Invoice (USD)

node {baseDir}/scripts/create_invoice_usd.js <amount_cents> [--timeout <seconds>] [--no-subscribe] [memo...]

Creates a Lightning invoice denominated in USD cents. The sender pays in BTC/Lightning, but the received amount is locked to a USD value at the current exchange rate. Credited to the USD wallet. Expires in ~5 minutes due to exchange rate lock.

Auto-subscribe: Same two-phase output as create_invoice.js — first JSON is the created invoice, second JSON is the payment resolution (PAID/EXPIRED/TIMEOUT).

• amount_cents — amount in USD cents, e.g. 100 = $1.00 (required)
• --timeout <seconds> — subscription timeout (default: 300). Use 0 for no timeout.
• --no-subscribe — skip WebSocket auto-subscribe, just create the invoice and exit
• memo... — optional description attached to the invoice (remaining args joined)

Check Invoice Status

node {baseDir}/scripts/check_invoice.js <payment_hash>

Checks the payment status of a Lightning invoice by its payment hash. Use after creating an invoice to detect when it has been paid. Returns status: PAID, PENDING, or EXPIRED.

• payment_hash — the 64-char hex payment hash from create_invoice.js output (required)

Pay Lightning Invoice

node {baseDir}/scripts/pay_invoice.js <bolt11_invoice> [--wallet BTC|USD] [--dry-run] [--force]

Pays a BOLT-11 Lightning invoice from the BTC or USD wallet. Returns payment status: SUCCESS, PENDING, FAILURE, or ALREADY_PAID. The wallet ID is resolved automatically.

• bolt11_invoice — the BOLT-11 payment request string, e.g. lnbc... (required)
• --wallet BTC|USD — wallet to pay from (default: BTC). When USD is selected, the Blink API debits the USD equivalent from the USD wallet.
• --dry-run — preview the payment without sending (returns wallet info and invoice details)
• --force — attempt payment even when the wallet balance appears insufficient

Requires Write scope on the API key.

AGENT: This command spends funds. Always run balance.js and fee_probe.js first, then confirm amount and recipient with the user before executing.

Pay to Lightning Address

node {baseDir}/scripts/pay_lnaddress.js <lightning_address> <amount_sats> [--wallet BTC|USD] [--dry-run] [--force] [--max-amount <sats>]

Sends satoshis to a Lightning Address (e.g. user@blink.sv). Returns payment status. The wallet ID is resolved automatically.

• lightning_address — recipient in user@domain format (required)
• amount_sats — amount in satoshis (required)
• --wallet BTC|USD — wallet to pay from (default: BTC). When USD is selected, the amount is still specified in satoshis; the Blink API debits the USD equivalent from the USD wallet automatically.
• --dry-run — preview the payment without sending (returns wallet info and amount details)
• --force — attempt payment even when the wallet balance appears insufficient
• --max-amount <sats> — reject the payment if the amount exceeds this ceiling (in satoshis)

Requires Write scope on the API key.

AGENT: This command spends funds. Always run balance.js first, confirm the Lightning Address and amount with the user, then execute.

Pay to LNURL

node {baseDir}/scripts/pay_lnurl.js <lnurl> <amount_sats> [--wallet BTC|USD] [--dry-run] [--force] [--max-amount <sats>]

Sends satoshis to a raw LNURL payRequest string. For Lightning Addresses (user@domain), use pay_lnaddress.js instead.

• lnurl — LNURL string, e.g. lnurl1... (required)
• amount_sats — amount in satoshis (required)
• --wallet BTC|USD — wallet to pay from (default: BTC). When USD is selected, the amount is still specified in satoshis; the Blink API debits the USD equivalent from the USD wallet automatically.
• --dry-run — preview the payment without sending (returns wallet info and amount details)
• --force — attempt payment even when the wallet balance appears insufficient
• --max-amount <sats> — reject the payment if the amount exceeds this ceiling (in satoshis)

Requires Write scope on the API key.

AGENT: This command spends funds. Always run balance.js first, confirm the LNURL and amount with the user, then execute.

Estimate Payment Fee

node {baseDir}/scripts/fee_probe.js <bolt11_invoice> [--wallet BTC|USD]

Estimates the fee for paying a Lightning invoice without actually sending. Use before pay_invoice.js to check costs. Payments to other Blink users and direct-channel nodes are free (0 sats).

• bolt11_invoice — the BOLT-11 payment request string (required)
• --wallet BTC|USD — wallet to probe from (default: BTC). When USD is selected, uses lnUsdInvoiceFeeProbe to estimate fees from the USD wallet's perspective.

Render Invoice QR Code

node {baseDir}/scripts/qr_invoice.js <bolt11_invoice>

Renders a terminal QR code for a Lightning invoice (BOLT-11) to stderr and generates a PNG image file to /tmp. The stdout JSON includes a pngPath field with the absolute path to the PNG file.

Sending the QR image to a user: After running this script, use the pngPath from the JSON output to send the PNG as a media attachment to the user in the current chat. The agent should use its native message-send capability with the file path.

• bolt11_invoice — the BOLT-11 payment request string (required)

Output JSON includes:

• invoice — uppercased invoice string
• qrRendered — always true
• qrSize — QR module count
• errorCorrection — "L" (LOW)
• pngPath — absolute path to the generated PNG file (e.g. /tmp/blink_qr_1234567890.png)
• pngBytes — file size in bytes

List Transactions

node {baseDir}/scripts/transactions.js [--first N] [--after CURSOR] [--wallet BTC|USD]

Lists recent transactions (incoming and outgoing) with pagination. Returns direction, amount, status, type (lightning/onchain/intraledger), and metadata.

• --first N — number of transactions to return (default: 20, max: 100)
• --after CURSOR — pagination cursor from previous response's endCursor
• --wallet BTC|USD — filter to a specific wallet currency

Get BTC/USD Price

node {baseDir}/scripts/price.js [amount_sats]
node {baseDir}/scripts/price.js --usd <amount_usd>
node {baseDir}/scripts/price.js --history <range>
node {baseDir}/scripts/price.js --currencies

Multi-purpose exchange rate tool. All price queries are public (no API key required), though the key is sent if available.

Modes:

• No args — current BTC/USD price and sats-per-dollar rate
• <amount_sats> — convert a satoshi amount to USD (e.g. price.js 1760 → $1.20)
• --usd <amount> — convert a USD amount to sats (e.g. price.js --usd 5.00 → 7350 sats)
• --history <range> — historical BTC price data with summary stats (high/low/change). Ranges: ONE_DAY, ONE_WEEK, ONE_MONTH, ONE_YEAR, FIVE_YEARS
• --currencies — list all supported display currencies (IDs, names, symbols, flags)

Account Info

node {baseDir}/scripts/account_info.js

Shows account level, spending limits (withdrawal, internal send, convert), default wallet, and wallet summary with pre-computed USD estimates for BTC balances. Limits are denominated in USD cents with a rolling 24-hour window.

Quote Internal BTC <-> USD Swap

node {baseDir}/scripts/swap_quote.js <direction> <amount> [--unit sats|cents] [--ttl-seconds N] [--immediate]

Builds a deterministic quote-like receipt for internal wallet conversion.

• direction — btc-to-usd or usd-to-btc
• amount — positive integer amount (unit inferred by direction unless --unit is set)
• --unit sats|cents — optional override for input unit
• --ttl-seconds N — quote validity window in seconds (default: 60)
• --immediate — mark intent for immediate execution mode in quote receipt

Uses Blink's conversion estimation path for pricing and records:

• pre-swap balances
• quote id / expiry metadata
• amount in/out terms
• execution path (intraLedgerPaymentSend or intraLedgerUsdPaymentSend)

Execute Internal BTC <-> USD Swap

node {baseDir}/scripts/swap_execute.js <direction> <amount> [--unit sats|cents] [--ttl-seconds N] [--immediate] [--dry-run] [--memo "text"]

Executes a wallet-native internal conversion between your BTC and USD wallets.

• --dry-run — returns an execution receipt without performing the mutation
• --memo "text" — optional memo attached to the internal transfer

Execution receipts include quote terms, pre/post balances, balance deltas, and final status.

Fee/settlement interpretation:

• quote.feeSats, quote.feeBps, and quote.slippageBps are currently returned as zero in live runs.
• You can still see a small quote-to-settlement spread (often 1 sat or 1 cent) due to integer rounding between sats and cents.
• Always compute effective cost from quote.amountOut versus balanceDelta instead of relying only on explicit fee fields.

For deeper behavior details and formulas, see swap-operations.

AGENT: This command moves funds between wallets. Always run with --dry-run first, show the quote to the user, and get explicit confirmation before executing without --dry-run.

Realtime Subscriptions

Blink supports GraphQL subscriptions over WebSocket using the graphql-transport-ws protocol. Node 20 requires the --experimental-websocket flag.

Subscribe to Invoice Payment Status

node --experimental-websocket {baseDir}/scripts/subscribe_invoice.js <bolt11_invoice> [--timeout <seconds>]

Watches a single invoice and exits when it is PAID or EXPIRED. Status updates are printed to stderr. JSON result is printed to stdout.

Subscribe to Account Updates (myUpdates)

node --experimental-websocket {baseDir}/scripts/subscribe_updates.js [--timeout <seconds>] [--max <count>]

Streams account updates in real time. Each event is output as a JSON line (NDJSON) to stdout. Use --max to stop after N events.

API Reference

API Endpoint: https://api.blink.sv/graphql (production) Authentication: X-API-KEY header

USD wallet notes: The lnInvoicePaymentSend, lnAddressPaymentSend, and lnurlPaymentSend mutations all accept either a BTC or USD wallet ID. When a USD wallet ID is provided, the API debits the USD equivalent automatically. Amounts for lnAddressPaymentSend and lnurlPaymentSend are always specified in satoshis regardless of wallet type.

Output Format

All scripts output structured JSON to stdout. Status messages and errors go to stderr. Exit code 0 on success, 1 on failure.

Balance output example

{
  "wallets": [
    { "id": "abc123", "currency": "BTC", "balance": 1760, "unit": "sats" },
    { "id": "def456", "currency": "USD", "balance": 1500, "unit": "cents" }
  ],
  "btcWalletId": "abc123",
  "btcBalance": 1760,
  "btcBalanceSats": 1760,
  "btcBalanceUsd": 1.2,
  "btcBalanceUsdFormatted": "$1.20",
  "usdWalletId": "def456",
  "usdBalance": 1500,
  "usdBalanceCents": 1500,
  "usdBalanceFormatted": "$15.00"
}

Invoice creation output example (two-phase)

First JSON (immediate):

{
  "event": "invoice_created",
  "paymentRequest": "lnbc500n1...",
  "paymentHash": "abc123...",
  "satoshis": 500,
  "status": "PENDING",
  "createdAt": "2026-02-23T00:00:00Z",
  "walletId": "abc123"
}

Second JSON (when payment resolves):

{
  "event": "subscription_result",
  "paymentRequest": "lnbc500n1...",
  "status": "PAID",
  "isPaid": true,
  "isExpired": false,
  "isPending": false
}

Invoice status output example

{
  "paymentHash": "abc123...",
  "paymentStatus": "PAID",
  "satoshis": 500,
  "isPaid": true,
  "isExpired": false,
  "isPending": false
}

Payment output example (BTC wallet)

{
  "status": "SUCCESS",
  "walletId": "abc123",
  "walletCurrency": "BTC",
  "balanceBefore": 50000
}

Payment output example (USD wallet)

{
  "status": "SUCCESS",
  "walletId": "def456",
  "walletCurrency": "USD",
  "balanceBefore": 1500,
  "balanceBeforeFormatted": "$15.00"
}

Price output example

{
  "btcPriceUsd": 68036.95,
  "satsPerDollar": 1470,
  "conversion": {
    "sats": 1760,
    "usd": 1.2,
    "usdFormatted": "$1.20"
  }
}

USD-to-sats conversion output example

{
  "btcPriceUsd": 68036.95,
  "satsPerDollar": 1470,
  "conversion": {
    "usd": 5.0,
    "usdFormatted": "$5.00",
    "sats": 7350
  }
}

Price history output example

{
  "range": "ONE_DAY",
  "dataPoints": 24,
  "summary": {
    "current": 68036.95,
    "oldest": 67500.00,
    "high": 68500.00,
    "low": 67200.00,
    "changeUsd": 536.95,
    "changePct": 0.8
  },
  "prices": [
    { "timestamp": 1740000000, "date": "2025-02-20T00:00:00.000Z", "btcPriceUsd": 67500.00 }
  ]
}

Transaction list output example

{
  "transactions": [
    {
      "id": "tx_123",
      "direction": "RECEIVE",
      "status": "SUCCESS",
      "amount": 1000,
      "currency": "BTC",
      "type": "lightning",
      "paymentHash": "abc...",
      "createdAt": 1740000000
    }
  ],
  "count": 1,
  "pageInfo": {
    "hasNextPage": false,
    "endCursor": "cursor_abc"
  }
}

Swap quote output example

{
  "event": "swap_quote",
  "dryRun": true,
  "direction": "BTC_TO_USD",
  "preBalance": {
    "btcWalletId": "btc_wallet_id",
    "usdWalletId": "usd_wallet_id",
    "btcBalanceSats": 250000,
    "usdBalanceCents": 150000
  },
  "quote": {
    "quoteId": "blink-swap-1740000000-424242",
    "amountIn": { "value": 5000, "unit": "sats" },
    "amountOut": { "value": 340, "unit": "cents" },
    "expiresAtEpochSeconds": 1740000060,
    "immediateExecution": false,
    "executionPath": "blink:intraLedgerPaymentSend"
  }
}

Swap execution output example

{
  "event": "swap_execution",
  "dryRun": false,
  "direction": "USD_TO_BTC",
  "status": "SUCCESS",
  "succeeded": true,
  "preBalance": {
    "btcBalanceSats": 250000,
    "usdBalanceCents": 150000
  },
  "postBalance": {
    "btcBalanceSats": 253650,
    "usdBalanceCents": 149500
  },
  "balanceDelta": {
    "btcDeltaSats": 3650,
    "usdDeltaCents": -500
  },
  "quote": {
    "quoteId": "blink-swap-1740000015-556677",
    "executionPath": "blink:intraLedgerUsdPaymentSend"
  },
  "execution": {
    "path": "blink:intraLedgerUsdPaymentSend",
    "transactionId": "tx_abc123"
  }
}

Typical Agent Workflows

Receive a payment (recommended — auto-subscribe + QR image)

# 1. Create invoice — script auto-subscribes and outputs two JSON objects
node {baseDir}/scripts/create_invoice.js 1000 "Payment for service"
# → First JSON: {"event": "invoice_created", "paymentRequest": "lnbc...", ...}
# → Read paymentRequest from first JSON immediately

# 2. Generate QR code PNG
node {baseDir}/scripts/qr_invoice.js <paymentRequest>
# → JSON includes "pngPath": "/tmp/blink_qr_123456.png"
# → Send the PNG file to the user as a media attachment in the current chat

# 3. The create_invoice.js script is still running, waiting for payment
# → Second JSON: {"event": "subscription_result", "status": "PAID", ...}
# → When PAID: notify the user that payment has been received
# → When EXPIRED: notify the user the invoice expired

Important: The create_invoice.js script outputs two JSON objects separated by a newline. Parse them as separate JSON objects, not as a single JSON array. The first object arrives immediately; the second arrives when payment status resolves.

Receive a payment (polling fallback)

# 1. Create invoice without auto-subscribe
node {baseDir}/scripts/create_invoice.js 1000 --no-subscribe "Payment for service"
# 2. Give the paymentRequest to the payer
# 3. Poll for payment
node {baseDir}/scripts/check_invoice.js <payment_hash>
# 4. Verify balance
node {baseDir}/scripts/balance.js

Receive a USD payment

# Same two-phase pattern as BTC, but using create_invoice_usd.js
# Note: USD invoices expire in ~5 minutes
node {baseDir}/scripts/create_invoice_usd.js 500 "Five dollars for service"
# → First JSON: {"event": "invoice_created", "amountCents": 500, "amountUsd": "$5.00", ...}
# Generate QR and send to user, then wait for second JSON

Send a payment (with fee check)

# 1. Check current balance
node {baseDir}/scripts/balance.js
# 2. Estimate fee
node {baseDir}/scripts/fee_probe.js lnbc1000n1...
# 3. Send payment
node {baseDir}/scripts/pay_invoice.js lnbc1000n1...
# 4. Verify in transaction history
node {baseDir}/scripts/transactions.js --first 1

Send from the USD wallet

# Pay an invoice from the USD wallet
node {baseDir}/scripts/fee_probe.js lnbc1000n1... --wallet USD
node {baseDir}/scripts/pay_invoice.js lnbc1000n1... --wallet USD

# Send to a Lightning Address from the USD wallet
node {baseDir}/scripts/pay_lnaddress.js user@blink.sv 1000 --wallet USD

# Send via LNURL from the USD wallet
node {baseDir}/scripts/pay_lnurl.js lnurl1... 1000 --wallet USD

# Note: for lnaddress and lnurl, the amount is always in satoshis.
# The Blink API debits the USD equivalent from the USD wallet automatically.

Convert sats to USD value

# Check how much 1760 sats is worth in USD
node {baseDir}/scripts/price.js 1760
# → $1.20

Convert USD to sats

# How many sats is $5.00?
node {baseDir}/scripts/price.js --usd 5.00
# → 7350 sats

Swap BTC to USD (quote then execute)

# 1. Build quote and inspect terms
node {baseDir}/scripts/swap_quote.js btc-to-usd 10000

# 2. Execute the swap
node {baseDir}/scripts/swap_execute.js btc-to-usd 10000

Swap USD to BTC (dry-run then execute)

# 1. Dry-run execution receipt without moving funds
node {baseDir}/scripts/swap_execute.js usd-to-btc 500 --unit cents --dry-run

# 2. Real execution
node {baseDir}/scripts/swap_execute.js usd-to-btc 500 --unit cents

Check price history

# Get BTC price over the last 24 hours
node {baseDir}/scripts/price.js --history ONE_DAY
# Get BTC price over the last month
node {baseDir}/scripts/price.js --history ONE_MONTH

Security

API Key Handling

• Your API key is your wallet access — anyone with a Write-scoped key can spend your entire balance.
• Use minimum scopes — Read-only for balance checks, Receive for invoices, Write only when sending.
• Never expose keys in output — do not echo, log, or include BLINK_API_KEY in chat messages or files.
• Keys are for server-side / agent use only. Never embed in client-side code.

What Data Leaves the Machine

• Outbound HTTPS to api.blink.sv (or BLINK_API_URL override) for all GraphQL queries and mutations.
• Outbound WSS to ws.blink.sv (or BLINK_WS_URL override) for subscription WebSockets.
• No other network calls. Scripts do not phone home, send telemetry, or contact any third-party services.

Filesystem Access

• RC file reading: If BLINK_API_KEY is not found in process.env, the client scans ~/.profile, ~/.bashrc, ~/.bash_profile, and ~/.zshrc for a line matching export BLINK_API_KEY=.... Only the value of that specific export is extracted — no other data is read from these files. The environment variable is always checked first.
• QR PNG generation: The qr command writes temporary PNG files to /tmp/blink_qr_*.png. These are standard image files with no embedded metadata beyond the QR content.
• No other filesystem writes. Scripts do not create config files, databases, or caches.

Stateless Design

This skill stores no data between runs. There are no databases, config files, session tokens, or caches. Each script invocation is independent — it reads the API key, makes API calls, outputs JSON, and exits.

Payment Safety

• Sending is irreversible — Lightning payments cannot be reversed once settled.
• Test on staging first — use BLINK_API_URL=https://api.staging.blink.sv/graphql to point at the signet staging environment with test funds.
• USD invoices expire fast — ~5 minutes due to exchange rate lock.
• Price queries are public — price.js works without an API key; only wallet operations require authentication.

Reference Files

• blink-api-and-auth: API endpoints, authentication, scopes, staging/testnet configuration, and error handling.
• payment-operations: send workflows, BTC vs USD wallet selection, fee probing, and safety guardrails.
• invoice-lifecycle: invoice creation, two-phase output parsing, monitoring strategies, QR generation, and expiration handling.
• swap-operations: wallet-native BTC<->USD conversion flows, quote/execution receipts, and fallback behavior.

Files

• {baseDir}/scripts/balance.js — Check wallet balances
• {baseDir}/scripts/create_invoice.js — Create BTC Lightning invoices (auto-subscribes to payment status)
• {baseDir}/scripts/create_invoice_usd.js — Create USD-denominated Lightning invoices (auto-subscribes to payment status)
• {baseDir}/scripts/check_invoice.js — Check invoice payment status (polling)
• {baseDir}/scripts/pay_invoice.js — Pay BOLT-11 invoices (BTC or USD wallet)
• {baseDir}/scripts/pay_lnaddress.js — Pay to Lightning Addresses (BTC or USD wallet)
• {baseDir}/scripts/pay_lnurl.js — Pay to LNURL strings (BTC or USD wallet)
• {baseDir}/scripts/fee_probe.js — Estimate payment fees (BTC or USD wallet)
• {baseDir}/scripts/qr_invoice.js — Render invoice QR code (terminal + PNG file)
• {baseDir}/scripts/transactions.js — List transaction history
• {baseDir}/scripts/price.js — Get BTC/USD exchange rate
• {baseDir}/scripts/account_info.js — Show account info and limits
• {baseDir}/scripts/swap_quote.js — Build BTC<->USD swap quote receipts (dry-run)
• {baseDir}/scripts/swap_execute.js — Execute BTC<->USD wallet-native swaps (or dry-run receipts)
• {baseDir}/scripts/subscribe_invoice.js — Subscribe to invoice payment status (standalone)
• {baseDir}/scripts/subscribe_updates.js — Subscribe to realtime account updates