Product
Open SourceSpring Boot starter for Lightning payment-gated APIs
Paygate lets Spring Boot developers protect endpoints with a single annotation, issue HTTP 402 payment challenges, and accept Bitcoin Lightning credentials through L402 or the draft Payment authentication flow.
Quickstart
Paygate is publicly available as a Spring Boot starter for payment-gated APIs. The examples below show the released developer experience.
Green Harbor Labsdependencies {
implementation("com.greenharborlabs:paygate-spring-boot-starter:0.1.4")
}<dependency>
<groupId>com.greenharborlabs</groupId>
<artifactId>paygate-spring-boot-starter</artifactId>
<version>0.1.4</version>
</dependency>@GetMapping("/trust/report")
@PaymentRequired(priceSats = 30)
TrustReport report(@RequestParam String domain) {
return trustReports.generate(domain);
}HTTP/1.1 402 Payment Required
WWW-Authenticate: L402 invoice="<bolt11>", macaroon="<token>"
WWW-Authenticate: Payment invoice="<bolt11>", amount="30sat"
{
"error": "payment_required",
"retry": "pay invoice and repeat the request"
}paygate:
backend: lnbits
default-price-sats: 30
lnbits:
url: ${LNBITS_URL}
api-key: ${LNBITS_API_KEY}
# backend: lnd is supported for node-direct deploymentsMost API monetization stacks are built around accounts, subscriptions, and human checkout flows. Agent and machine clients need a protocol-native way to pay per request without custom billing infrastructure.
Paygate auto-configures Spring Boot filters, protocol handlers, Lightning backends, credential validation, and observability. Developers add `@PaymentRequired`, configure LNbits or LND, and unpaid requests receive a 402 challenge instead of protected content.
As agents consume more APIs directly, payment and authorization need to become programmable, metered, and machine-readable. Paygate gives Java teams a concrete path to sell API access over Lightning without building the payment protocol layer from scratch.
Built with Paygate
A Spring Boot reference service that sells signed agent trust reports behind Paygate payment challenges.
Paygate Agent Trust exposes free catalog and quote APIs, then protects trust report generation with Paygate. Program clients can request a report, receive a Lightning payment challenge, pay the invoice, and retry for a signed JSON response.
Reference service
A live reference service with real LNbits settlement shows the full unpaid request, Lightning invoice, paid retry, and signed JSON response loop.