Crypto in. Naira settled.
One API.

API access is issued to registered businesses after a short due-diligence review (KYB). To request keys, write to [email protected] with your company name, RC number, website, expected monthly volume, and the corporate bank account that should receive settlements. Most reviews complete within two business days.

You'll receive two key pairs — sk_test_… for the sandbox and sk_live_… for production — plus a whsec_… webhook signing secret for each environment. Send your key on every request:

# Every request
Authorization: Bearer sk_live_9f2c7a1e4b8d…
Content-Type: application/json

Register an HTTPS endpoint during onboarding (or change it later via [email protected]). Every event is a POST with a JSON body and two headers you must verify.

# Delivery — example: deposit.confirmed
POST https://yourapp.com/webhooks/monica
X-Monica-Timestamp: 1783158079
X-Monica-Signature: 6e8c1d0a94b7f3…

{
  "id":         "evt_01JXK7RS0P2Q",
  "type":       "deposit.confirmed",
  "created_at": "2026-07-06T09:41:19Z",
  "data": {
    "deposit_id":    "dep_01JXK7RQ83VD",
    "wallet_id":     "wal_01JXK4N9Q2M7",
    "customer_ref":  "user_8841",
    "asset":         "USDT",
    "network":       "TRC20",
    "amount":        "150.000000",
    "txid":          "b2a4c9f7e1d8…",
    "confirmations": 1,
    "rate_ngn":      "1621.50",
    "ngn_amount":    "243225.00",
    "status":        "confirmed"
  }
}

Verifying signatures

Compute an HMAC-SHA256 over timestamp + "." + raw_body with your whsec_… secret and compare it, constant-time, to X-Monica-Signature. Reject anything older than 5 minutes.

# Pseudocode — any language
payload  = header("X-Monica-Timestamp") + "." + raw_request_body
expected = hex( hmac_sha256(key: WEBHOOK_SECRET, message: payload) )

if !constant_time_equals(expected, header("X-Monica-Signature")): reject 401
if abs(now() - header("X-Monica-Timestamp")) > 300:               reject 401
process(event)
respond 200

# Every error, same shape
{
  "error": {
    "code":    "unsupported_network",
    "message": "USDT is not available on network BITCOIN.",
    "param":   "network"
  }
}

Everything above works identically at https://sandbox.api.monica.cash/v1 with your sk_test_… key. Sandbox wallets accept testnet coins (TRC20 Shasta, Ethereum Sepolia, Bitcoin testnet3, Solana devnet), confirmations are accelerated, and settlements post to a virtual ledger you can inspect at GET /v1/settlements — no real bank movement, no real crypto. Webhooks fire exactly as in production, signed with your test whsec_….

Monica is a direct crypto-to-naira off-ramp operated by Monica Technologies Limited, Lagos, aligned with Nigeria's SEC VASP framework. We do not provide custodial wallet services: a deposit address issued through this API is a settlement endpoint, and on on-chain confirmation title to the crypto passes to Monica's treasury against our obligation to settle naira to your account. Partners must be registered businesses, complete KYB, and remain responsible for KYC on their own end users. Full terms are issued with your API agreement.