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This page gives you a 10,000‑ft view of an end‑to‑end Grid implementation for on and off-ramps. It is intentionally generalized to cover both on-ramp (fiat → crypto) and off-ramp (crypto → fiat) flows. The detailed guides that follow provide concrete fields, edge cases, and step‑by‑step instructions.
This overview highlights the main building blocks: platform setup, customer onboarding, account management, conversion flows, reconciliation, sandbox testing, and go‑live enablement.

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Platform configuration

Configure your platform once before building user flows.
  • Provide webhook endpoints for transaction and conversion status notifications
  • Generate API credentials for Sandbox (and later Production)
  • Configure supported currencies for conversions (fiat and crypto)
  • Review settlement methods and supported crypto destinations

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Onboarding customers

Onboard customers who will use ramp services. There are two patterns:
  • Regulated platforms can directly create customers by providing minimal KYC data via API
  • Unregulated entities should request a KYC link and embed the hosted KYC flow; once completed, the customer can transact
You’ll need to persist the Grid customer IDs for use in conversion flows.

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Account management

Set up accounts for funding and receiving conversions.

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Internal Accounts

  • Platform and customer internal accounts hold fiat or crypto balances
  • Used for pre-funded off-ramp scenarios (crypto → fiat)
  • Fund via ACH, wire, or crypto deposits

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External Accounts

  • Register crypto wallets (Spark, Bitcoin addresses) for on-ramp destinations
  • Register bank accounts for off-ramp destinations
  • Capture required beneficiary and account information
On-ramps typically deliver to external crypto wallets, while off-ramps typically deliver to external bank accounts.

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On-ramp flow (Fiat → Crypto)

Enable users to convert fiat currency to cryptocurrency.

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Quote Creation

  • Create a quote specifying source (fiat) and destination (crypto wallet)
  • Lock exchange rate and receive payment instructions
  • Quote includes reference code for payment matching

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Just-in-Time Funding

  • User sends fiat payment to provided bank account details
  • Include reference code in payment memo for matching
  • Grid detects payment and automatically executes conversion

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Crypto Delivery

  • Grid converts fiat to crypto at locked rate
  • Crypto delivered to specified wallet (Spark, Bitcoin, etc.)
  • Webhook notification confirms delivery
For JIT-funded quotes, do NOT call the execute endpoint. Grid automatically processes the conversion when it receives your payment.

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Off-ramp flow (Crypto → Fiat)

Enable users to convert cryptocurrency to fiat currency.

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Pre-funding

  • Customer or platform holds crypto in internal accounts
  • Balances can be funded via crypto deposits (Lightning, on-chain)

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Quote and Execution

  • Create a quote specifying source (crypto account) and destination (bank account)
  • Lock exchange rate and fees
  • Execute the quote to initiate conversion
  • Grid converts crypto to fiat and delivers to bank account

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Fiat Delivery

  • Fiat delivered via local banking rails
  • Settlement times vary by destination (instant to 1-3 business days)
  • Webhook notification confirms delivery

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Self-custody wallet integration

Support for sending crypto to user-controlled wallets.
  • Spark wallets: Lightning-compatible wallets for instant, low-fee Bitcoin transfers
  • Validation: Validate wallet addresses before creating external accounts
  • Limits: Verify minimum and maximum amounts for crypto transfers
  • Monitoring: Track transfer completion via webhooks
Spark wallets are recommended for crypto delivery as transfers complete within seconds with minimal fees.

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Reconciling transactions

Implement operational processes to keep your ledger in sync.
  • Process webhooks idempotently; map statuses (pending, processing, completed, failed)
  • Tie transactions back to quotes and customers
  • Track conversion rates and fees for accurate accounting
  • Query for transactions by date range or customer as necessary

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Testing in Sandbox

Use Sandbox to build and validate end‑to‑end without moving real funds.
  • Simulate fiat funding using /sandbox/send endpoint
  • Simulate crypto deposits using /sandbox/internal-accounts/{accountId}/fund endpoint or /transfer-in endpoint
  • Test quote creation, conversion, and webhook lifecycles
  • Validate customer onboarding flows with test data
See the Sandbox Testing page for more details.

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Enabling Production

When you’re ready to go live:
  • Ensure adequate funding mechanisms are in place (for off-ramps)
  • Confirm webhook security, monitoring, and alerting are configured
  • Review rate limits, error handling, and idempotency
  • Test conversion flows thoroughly in Sandbox
  • Run final UAT in Sandbox, then request Production access from our team
Contact our team to enable Production and begin processing real conversions.

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Support

If you need assistance with , please contact our support team at support@lightspark.com or visit our support portal at https://support.lightspark.com.
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