Sandbox Testing

The Grid sandbox environment simulates real payment flows without moving real money. You can control test outcomes using special account number patterns and test addresses.

KYC/KYB verification

In sandbox, you can trigger specific KYC/KYB verification outcomes using magic suffixes in customer and beneficial owner fields. These let you test different verification flows without waiting for real review.

Business customer verification

The last 3 digits of the registrationNumber in businessInfo determine the KYB status outcome when you call POST /verifications:

Suffix	`kybStatus`	Behavior
001	`PENDING`	KYB verification remains pending
002	`REJECTED`	KYB verification is rejected
Any other	`APPROVED`	KYB verification is approved

Beneficial owner KYC

The last 3 characters of the lastName in personalInfo determine the individual KYC status outcome:

Suffix	`kycStatus`	Behavior
001	`PENDING`	KYC verification remains pending
002	`REJECTED`	KYC verification is rejected
Any other	`APPROVED`	KYC verification is approved

Adding external accounts

The flows for creating external accounts in sandbox are the same as in production. The last 3 digits of an external account’s primary identifier (account number, IBAN, CLABE, Spark wallet address, etc.) determine the test scenario when that account is used in transfers or quotes. For identifiers with a domain part (e.g. PIX email keys), append the test digits to the username portion — for example, testuser.002@pix.com.br.

Beneficiary name verification

For account types that support beneficiary name verification, you can simulate different verification outcomes in sandbox. Use account identifiers with a 1xx suffix to trigger verification scenarios (this range is reserved for verification and does not conflict with transfer or quote test patterns):

Suffix	`beneficiaryVerificationStatus`	Behavior
102	`NOT_MATCHED`	Account is valid but name does not match
103	`PARTIAL_MATCH`	Account is valid, name is a fuzzy match
104	`PENDING`	Verification still in progress
105	(error)	Returns `400` — invalid account
106	`UNSUPPORTED`	Payment rail does not support name verification
107	`CHECKED_BY_RECEIVING_FI`	Verification deferred to receiving financial institution (e.g., ACH)
109	(error)	Returns `500` — simulated API error
Any other	`MATCHED`	Account is valid, name matches exactly

Transfer in

In production, internal accounts are funded by sending a bank transfer to the account’s payment instructions or by pulling from an external account. In sandbox, you have two options:

Transfer in from an external account

Use the /transfer-in endpoint to pull funds from an external account into an internal account. The external account’s number suffix determines the outcome:

Suffix	Behavior
002	Insufficient funds — transfer fails immediately
003	Account closed/invalid — transfer fails immediately
004	Transfer rejected — bank rejects the transfer
005	Timeout/delayed failure — stays pending ~30s, then fails
Any other	Success — transfer completes normally

Sandbox fund endpoint

Instantly add funds to any internal account using /sandbox/internal-accounts/{accountId}/fund:

curl -X POST https://api.lightspark.com/grid/2025-10-13/sandbox/internal-accounts/{accountId}/fund \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{ "amount": 100000 }'

Creating quotes (cross-currency transfers)

When creating a quote with an external account destination, the account number suffix determines the payment outcome after quote execution:

Suffix	Behavior
002	Quote execution failed
003	Long payment — completes after approximately 6 minutes
004	Counterparty delivery failed
005	Receiving bank returned payment (completes then transitions to failed)
006	User cancellation
007	Payout and refund failed
Any other	Successful payment

Executing a quote

After creating a quote, you need to fund it to trigger execution. There are two ways to do this in sandbox: Prefunded internal account — If your quote’s source is an internal account, fund the account using one of the methods described in transfer in, then call the quote execute endpoint to trigger the transaction:

curl -X POST https://api.lightspark.com/grid/2025-10-13/quotes/{quoteId}/execute \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET"

Real-time funding via sandbox send — If your quote uses real-time funding, the quote response includes payment instructions for you to transfer funds to. Use /sandbox/send to simulate this payment:

curl -X POST https://api.lightspark.com/grid/2025-10-13/sandbox/send \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "quoteId": "Quote:019542f5-b3e7-1d02-0000-000000000006",
    "currencyCode": "USD"
  }'

Transferring out funds

Use the /transfer-out endpoint to push funds from an internal account to an external account in the same currency. The external account’s number suffix controls the outcome using the same patterns as transfer in.

Sending to a UMA address

For UMA-based payments, use these sandbox addresses to simulate different scenarios:

UMA Address	Behavior
`$success.usd@sandbox.uma.money`	Payment succeeds (USD)
`$success.eur@sandbox.uma.money`	Payment succeeds (EUR)
`$success.mxn@sandbox.uma.money`	Payment succeeds (MXN)
`$pending.long.usd@sandbox.uma.money`	Simulates a long-pending payment
`$fail.compliance.usd@sandbox.uma.money`	Simulates a compliance check failure

Simulating incoming UMA payments

Use the sandbox receive endpoint to simulate an incoming UMA payment to one of your platform’s users:

curl -X POST https://api.lightspark.com/grid/2025-10-13/sandbox/uma/receive \
  -u "$GRID_CLIENT_ID:$GRID_CLIENT_SECRET" \
  -H "Content-Type: application/json" \
  -d '{
    "senderUmaAddress": "$success.usd@sandbox.uma.money",
    "receiverUmaAddress": "$your.user@your.domain",
    "receivingCurrencyCode": "USD",
    "receivingCurrencyAmount": 5000
  }'

Using the API

API documentation

KYC/KYB verification

Business customer verification

Beneficial owner KYC

Adding external accounts

Beneficiary name verification

Transfer in

Transfer in from an external account

Sandbox fund endpoint

Creating quotes (cross-currency transfers)

Executing a quote

Transferring out funds

Sending to a UMA address

Simulating incoming UMA payments

​KYC/KYB verification

​Business customer verification

​Beneficial owner KYC

​Adding external accounts

​Beneficiary name verification

​Transfer in

​Transfer in from an external account

​Sandbox fund endpoint

​Creating quotes (cross-currency transfers)

​Executing a quote

​Transferring out funds

​Sending to a UMA address

​Simulating incoming UMA payments

KYC/KYB verification

Business customer verification

Beneficial owner KYC

Adding external accounts

Beneficiary name verification

Transfer in

Transfer in from an external account

Sandbox fund endpoint

Creating quotes (cross-currency transfers)

Executing a quote

Transferring out funds

Sending to a UMA address

Simulating incoming UMA payments