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

# Signing Requests

Sign the request using your Ed25519 private key. The **sign data** is built by joining the sorted query string, the raw request body, and a Unix timestamp with `\n`:

```
sign_data = sorted_query_string + "\n" + body + "\n" + timestamp
```

* **sorted\_query\_string** — query parameters sorted alphabetically by key, formatted as `key1=value1&key2=value2`. Empty string when there are no query parameters.
* **body** — the raw request body (byte-for-byte). Empty string for requests with no body.
* **timestamp** — Unix timestamp in seconds. Send the same value in the `X-HSPay-Timestamp` header.

Include the base64-encoded signature in the `X-HSPay-Signature` header and the timestamp in the `X-HSPay-Timestamp` header.

#### Go Example

```go theme={null}
package main

import (
    "crypto/ed25519"
    "encoding/base64"
    "fmt"
    "net/url"
    "sort"
    "strings"
    "time"
)

// buildSortedQueryString sorts query parameters by key.
func buildSortedQueryString(query url.Values) string {
    keys := make([]string, 0, len(query))
    for k := range query {
        keys = append(keys, k)
    }
    sort.Strings(keys)

    pairs := make([]string, 0, len(keys))
    for _, k := range keys {
        pairs = append(pairs, k+"="+query.Get(k))
    }
    return strings.Join(pairs, "&")
}

// signRequest signs the request using Ed25519.
// signData = sorted_query_string + "\n" + body + "\n" + timestamp
func signRequest(privateKeyB64 string, queryString string, body []byte) (signature string, timestamp string) {
    privateKey, _ := base64.StdEncoding.DecodeString(privateKeyB64)
    ts := fmt.Sprintf("%d", time.Now().Unix())
    signData := queryString + "\n" + string(body) + "\n" + ts
    sig := ed25519.Sign(ed25519.PrivateKey(privateKey), []byte(signData))
    return base64.StdEncoding.EncodeToString(sig), ts
}

func verifySignature(publicKeyB64 string, queryString string, body []byte, timestampStr string, signatureB64 string) bool {
    publicKey, _ := base64.StdEncoding.DecodeString(publicKeyB64)
    signData := queryString + "\n" + string(body) + "\n" + timestampStr
    signature, _ := base64.StdEncoding.DecodeString(signatureB64)
    return ed25519.Verify(ed25519.PublicKey(publicKey), []byte(signData), signature)
}
```