> ## Documentation Index
> Fetch the complete documentation index at: https://docs.orsunpay.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Server SDKs

> Integrate merchant payments, payouts, refunds, payment links and signed webhooks in your backend language.

Choose the client for your server. Each SDK uses the HTTPS API origin assigned to your merchant, your merchant ID, and a test or live API key. Obtain the package or source distribution from your OrsunPay integration contact.

| Language | Requirements | Start here |
| - | - | - |
| JavaScript / TypeScript | Node.js 20+, ESM or CommonJS | [Node.js SDK](https://docs.orsunpay.com/sdks/node.md) |
| Go | Go 1.22+ | [Go SDK](https://docs.orsunpay.com/sdks/go.md) |
| PHP | 64-bit PHP 8.1+, PSR-18 transport and PSR-17 factories | [PHP SDK](https://docs.orsunpay.com/sdks/php.md) |
| Java / Kotlin | JVM 17+, Maven-compatible | [Java SDK](https://docs.orsunpay.com/sdks/java.md) |
| C# | .NET 8+ | [.NET SDK](https://docs.orsunpay.com/sdks/dotnet.md) |
| Python | Python 3.11+, synchronous or asyncio | [Python SDK](https://docs.orsunpay.com/sdks/python.md) |
| Ruby / Rails | Ruby 3.1+, Bundler for Rails | [Ruby SDK](https://docs.orsunpay.com/sdks/ruby.md) |
| Rust | Rust 1.90+, Tokio | [Rust SDK](https://docs.orsunpay.com/sdks/rust.md) |

All eight clients create sales and payouts, look up and list payments, manage payment links, request and track refunds, and verify webhook signatures. Store the order reference and a stable idempotency key before sending a write. A successful HTTP response can still describe a pending or declined payment. [First payment](https://docs.orsunpay.com/quickstart.md) · [Payment states](https://docs.orsunpay.com/payments.md)

For operations outside your SDK's method list, including usage billing, use the [HTTP reference](https://docs.orsunpay.com/api-overview.md). For a browser checkout, use the [checkout widget](https://docs.orsunpay.com/js-widget.md) or [cashier](https://docs.orsunpay.com/cashier.md). Keep the merchant key on the server.


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