Bitcoin Payment API for Developers

The pricing and money flow diagram illustrates the cost-saving benefits of Nijipe compared to legacy processors and crypto gateways. While traditional services charge percentage-based processing fees (e.g., $320 or $100 on $10,000 of sales), Nijipe charges a flat $15/month SaaS fee with 0% transaction fees. The visual shows a direct money flow path: the customer sends funds directly to the merchant wallet. Nijipe sits outside the payment path, simply monitoring the transaction to provide API access and webhooks, ensuring the merchant's revenue scales while the software bill remains completely predictable.

Nijipe derives a unique Bitcoin receiving address for every invoice using the merchant's XPUB or ZPUB extended public key. The derivation follows the BIP84 standard path m/84'/0'/0'/0/{index}, where index is an integer stored in the database and incremented atomically on each invoice creation. This guarantees that no two invoices share a receiving address, which protects merchant privacy by preventing address reuse. Because derivation uses only the public extended key, it is mathematically impossible to derive private keys or spend funds from an XPUB or ZPUB. This is the same public-key derivation principle used by hardware wallets such as Ledger and Trezor. Merchants provide their ZPUB once during store setup. Nijipe stores it and handles all subsequent address generation automatically. Private keys never leave the merchant's wallet under any circumstances.

Nijipe supports non-custodial Lightning Network payments through its BYON (Bring Your Own Node) architecture. Merchants connect their own Lightning node — LND, Core Lightning, or Phoenixd — to their Nijipe store. When a Lightning invoice is created, Nijipe generates a BOLT11 payment request via the merchant's connected node. The customer pays directly to the merchant's node through Lightning Network routing. Nijipe monitors settlement via the node's invoice subscription stream and fires signed webhook events to the merchant's application on confirmation. Because payment routes to the merchant's own node, Nijipe never takes custody of Lightning funds. This contrasts with most hosted Lightning processors that pool merchant funds in a shared platform wallet and require withdrawal requests. BYON ensures the merchant's Lightning channels, balances, and funds remain entirely under merchant control.

Nijipe monitors Bitcoin transactions in real time using Bitcoin Core's ZMQ (ZeroMQ) pub/sub interface. The platform subscribes to two ZMQ streams: rawtx for mempool transactions and rawblock for confirmed blocks. When a new transaction is broadcast to the Bitcoin network, Nijipe's ZMQ listener parses the transaction outputs and checks each output address against the database of pending invoice addresses. If a match is found, the invoice status transitions from pending to payment_detected and a signed webhook fires to the merchant's endpoint immediately. Nijipe then monitors subsequent blocks for that transaction. When the transaction reaches the configured confirmation threshold (default: 1 confirmation), the invoice transitions to confirmed and a final webhook fires. If the received amount is less than 99% of the expected invoice total, the status is set to underpaid. If greater than 101%, it is set to overpaid. If no payment is detected before the invoice's expiresAt timestamp, the status transitions to expired. All nine invoice status values — pending, payment_detected, paid, confirmed, underpaid, overpaid, expired, canceled, and failed — trigger a corresponding signed HMAC-SHA256 webhook event to the merchant's configured endpoint.

The architecture comparison illustrates three models: Traditional Crypto Gateways, Self-Hosted Infrastructure, and Nijipe's Managed API Experience. Traditional gateways route customer payments into a centralized Gateway Wallet, freezing funds and requiring the merchant to make manual withdrawal requests, accompanied by high 0.5% to 1% fees. Self-Hosted Infrastructure routes funds directly to a Merchant Node, offering non-custodial control but burdening the merchant with high maintenance overhead, including managing Bitcoin Core, LND, mempool, and security patches. Nijipe bridges the gap by offering a Managed API Experience. Customers pay directly to the Merchant Wallet without Nijipe ever taking custody. Nijipe's infrastructure simply monitors the blockchain and fires webhook events to the merchant's application, providing the ease of a managed gateway with the non-custodial security and 0% transaction fees of a self-hosted node.