Seismic Card Issuance API

Prepaid cards are topped up from stablecoins deposited for the cardholder (applicant). Seismic exposes one receive address and a one-click fund call. You choose the product mode per program.

Mode	Who sends	Your job
`wallet_service` (default)	End-user (or you) to Seismic’s deposit address	Show deposit address → wait for balance → `fund-from-wallet`
`byo_wallet`	End-user from a wallet address you configure	Store their wallet → show deposit address → they send from that wallet → `fund-from-wallet`

Both modes use the same deposit address and the same POST /v1/cards/{id}/fund-from-wallet call. BYO only adds the configured send-from wallet on the program and on deposit-address responses.

Upstream issuer / crypto-rail names never appear in responses. You only see Seismic API fields.

1. Set the program funding mode

Wallet service (default)

curl -s -X PUT 'https://api.seismic-cards.systems/v1/programs/PROGRAM_ID/funding-config' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{
    "mode": "wallet_service",
    "preferred_chain": "BASE",
    "preferred_currency": "USDC"
  }'

Bring-your-own (BYO) wallet

byo.address is required — the user’s external wallet they will send from.

curl -s -X PUT 'https://api.seismic-cards.systems/v1/programs/PROGRAM_ID/funding-config' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{
    "mode": "byo_wallet",
    "preferred_chain": "BASE",
    "preferred_currency": "USDC",
    "byo": {
      "address": "0xUserWalletAddress",
      "chain": "BASE",
      "currency": "USDC",
      "provider": "metamask"
    }
  }'

Read back with GET /v1/programs/{id}/funding-config.

2. Get the deposit address

After the applicant has completed issuer KYC (issuerKycReady: true):

curl -s 'https://api.seismic-cards.systems/v1/applicants/APPLICANT_ID/funding/deposit-address?program_id=PROGRAM_ID&chain=BASE&currency=USDC' \
  -H 'Authorization: Bearer YOUR_TOKEN'

Example BYO response:

{
  "data": {
    "applicant_id": "app_abc123",
    "mode": "byo_wallet",
    "address": "0xDepositReceiveAddress",
    "currency": "USDC",
    "chain": "BASE",
    "instructions": "Send from your configured external wallet to this address, then call fund-from-wallet on the card.",
    "byo_wallet": {
      "address": "0xUserWalletAddress",
      "chain": "BASE",
      "currency": "USDC",
      "provider": "metamask"
    }
  }
}

address — always the receive address (send to this).
byo_wallet.address — only in byo_wallet mode; the configured send-from wallet.

3. Check balances

curl -s 'https://api.seismic-cards.systems/v1/applicants/APPLICANT_ID/funding/balances' \
  -H 'Authorization: Bearer YOUR_TOKEN'

Use available_to_fund_usd (or deposit balances) to know when you can top up the card.

4. Fund the card

curl -s -X POST 'https://api.seismic-cards.systems/v1/cards/CARD_ID/fund-from-wallet' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -H 'Idempotency-Key: fund-CARD_ID-25' \
  -d '{ "amount": "25.00" }'

This swaps deposited stables → USD and credits the prepaid card spend pot. Minimums are enforced by the rail (typically ≥ $0.50).

Flow

Errors to expect

Situation	Typical result
`byo_wallet` without `byo.address`	`400` — address required
Applicant KYC incomplete	`400` — no issuer account yet
Amount below rail minimum / insufficient deposit	`400` / issuer error
Wrong chain or currency	Deposit may not credit — match `preferred_*` / query params

Programs & accounts — create the program first
Cards — issue the prepaid card before funding
API reference: PUT /v1/programs/{id}/funding-config, GET …/funding/deposit-address, POST /v1/cards/{id}/fund-from-wallet

Get started

Core concepts

Reference

Card funding (wallet & BYO)

1. Set the program funding mode

Wallet service (default)

Bring-your-own (BYO) wallet

2. Get the deposit address

3. Check balances

4. Fund the card

Flow

Errors to expect

​1. Set the program funding mode

​Wallet service (default)

​Bring-your-own (BYO) wallet

​2. Get the deposit address

​3. Check balances

​4. Fund the card

​Flow

​Errors to expect

​Related

1. Set the program funding mode

Wallet service (default)

Bring-your-own (BYO) wallet

2. Get the deposit address

3. Check balances

4. Fund the card

Flow

Errors to expect

Related