diff --git a/src/main/kotlin/dev/usbharu/hideout/config/ActivityPubConfig.kt b/src/main/kotlin/dev/usbharu/hideout/config/ActivityPubConfig.kt
index 5e6c3016..e9786a1f 100644
--- a/src/main/kotlin/dev/usbharu/hideout/config/ActivityPubConfig.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/config/ActivityPubConfig.kt
@@ -7,6 +7,8 @@ import com.fasterxml.jackson.module.kotlin.jacksonObjectMapper
 import org.springframework.beans.factory.annotation.Qualifier
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
+import java.time.format.DateTimeFormatter
+import java.util.*
 
 @Configuration
 class ActivityPubConfig {
@@ -20,4 +22,8 @@ class ActivityPubConfig {
             .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
         return objectMapper
     }
+
+    @Bean
+    @Qualifier("http")
+    fun dateTimeFormatter(): DateTimeFormatter = DateTimeFormatter.ofPattern("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US)
 }
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestService.kt b/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestService.kt
new file mode 100644
index 00000000..4db4561b
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestService.kt
@@ -0,0 +1,23 @@
+package dev.usbharu.hideout.service.ap
+
+import dev.usbharu.hideout.domain.model.ap.Object
+import dev.usbharu.hideout.domain.model.hideout.entity.User
+
+interface APRequestService {
+    suspend fun <R : Object> apGet(url: String, signer: User? = null, responseClass: Class<R>): R
+    suspend fun <T : Object, R : Object> apPost(
+        url: String,
+        body: T? = null,
+        signer: User? = null,
+        responseClass: Class<R>
+    ): R
+}
+
+suspend inline fun <reified R : Object> APRequestService.apGet(url: String, signer: User? = null): R =
+    apGet(url, signer, R::class.java)
+
+suspend inline fun <T : Object, reified R : Object> APRequestService.apPost(
+    url: String,
+    body: T? = null,
+    signer: User? = null
+): R = apPost(url, body, signer, R::class.java)
diff --git a/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImpl.kt b/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImpl.kt
new file mode 100644
index 00000000..605184e1
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/service/ap/APRequestServiceImpl.kt
@@ -0,0 +1,121 @@
+package dev.usbharu.hideout.service.ap
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import dev.usbharu.hideout.domain.model.ap.Object
+import dev.usbharu.hideout.domain.model.hideout.entity.User
+import dev.usbharu.hideout.service.signature.HttpSignatureSigner
+import dev.usbharu.hideout.service.signature.Key
+import dev.usbharu.hideout.util.Base64Util
+import dev.usbharu.hideout.util.HttpUtil.Activity
+import dev.usbharu.hideout.util.RsaUtil
+import io.ktor.client.*
+import io.ktor.client.request.*
+import io.ktor.client.statement.*
+import io.ktor.http.*
+import org.springframework.beans.factory.annotation.Qualifier
+import org.springframework.stereotype.Service
+import java.net.URL
+import java.security.MessageDigest
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+
+@Service
+class APRequestServiceImpl(
+    private val httpClient: HttpClient,
+    @Qualifier("activitypub") private val objectMapper: ObjectMapper,
+    private val httpSignatureSigner: HttpSignatureSigner,
+    @Qualifier("http") private val dateTimeFormatter: DateTimeFormatter,
+) : APRequestService {
+
+    override suspend fun <R : Object> apGet(url: String, signer: User?, responseClass: Class<R>): R {
+
+        val date = dateTimeFormatter.format(LocalDateTime.now(ZoneId.of("GMT")))
+        val u = URL(url)
+        if (signer?.privateKey == null) {
+            val bodyAsText = httpClient.get(url) {
+                header("Accept", ContentType.Application.Activity)
+                header("Date", date)
+            }.bodyAsText()
+            return objectMapper.readValue(bodyAsText, responseClass)
+        }
+
+        val headers = headers {
+            append("Accept", ContentType.Application.Activity)
+            append("Date", date)
+            append("Host", u.host)
+        }
+
+        val sign = httpSignatureSigner.sign(
+            url, HttpMethod.Get, headers, "", Key(
+                keyId = "${signer.url}#pubkey",
+                privateKey = RsaUtil.decodeRsaPrivateKey(signer.privateKey),
+                publicKey = RsaUtil.decodeRsaPublicKey(signer.publicKey)
+            ), listOf("(request-target)", "date", "host", "accept")
+        )
+
+        val bodyAsText = httpClient.get(url) {
+            headers {
+                headers {
+                    appendAll(sign.headers)
+                    remove("Host")
+                }
+            }
+        }.bodyAsText()
+        return objectMapper.readValue(bodyAsText, responseClass)
+    }
+
+    override suspend fun <T : Object, R : Object> apPost(
+        url: String,
+        body: T?,
+        signer: User?,
+        responseClass: Class<R>
+    ): R {
+
+        val requestBody = objectMapper.writeValueAsString(body)
+
+        val sha256 = MessageDigest.getInstance("SHA-256")
+
+        val digest = Base64Util.encode(sha256.digest(requestBody.toByteArray()))
+
+        val date = dateTimeFormatter.format(LocalDateTime.now(ZoneId.of("GMT")))
+        val u = URL(url)
+        if (signer?.privateKey == null) {
+            val bodyAsText = httpClient.post(url) {
+                header("Accept", ContentType.Application.Activity)
+                header("ContentType", ContentType.Application.Activity)
+                header("Date", date)
+                header("Digest", digest)
+                setBody(requestBody)
+            }.bodyAsText()
+            return objectMapper.readValue(bodyAsText, responseClass)
+        }
+
+        val headers = headers {
+            append("Accept", ContentType.Application.Activity)
+            append("ContentType", ContentType.Application.Activity)
+            append("Date", date)
+            append("Host", u.host)
+            append("Digest", digest)
+        }
+
+        val sign = httpSignatureSigner.sign(
+            url, HttpMethod.Get, headers, "", Key(
+                keyId = "${signer.url}#pubkey",
+                privateKey = RsaUtil.decodeRsaPrivateKey(signer.privateKey),
+                publicKey = RsaUtil.decodeRsaPublicKey(signer.publicKey)
+            ), listOf("(request-target)", "date", "host", "digest")
+        )
+
+        val bodyAsText = httpClient.post(url) {
+            headers {
+                headers {
+                    appendAll(sign.headers)
+                    remove("Host")
+                }
+            }
+            setBody(requestBody)
+        }.bodyAsText()
+        return objectMapper.readValue(bodyAsText, responseClass)
+    }
+}