diff --git a/tosspay-mock/src/main/kotlin/com/sangdol/tosspaymock/business/TosspayService.kt b/tosspay-mock/src/main/kotlin/com/sangdol/tosspaymock/business/TosspayService.kt
new file mode 100644
index 00000000..4aa64069
--- /dev/null
+++ b/tosspay-mock/src/main/kotlin/com/sangdol/tosspaymock/business/TosspayService.kt
@@ -0,0 +1,111 @@
+package com.sangdol.tosspaymock.business
+
+import com.sangdol.common.persistence.IDGenerator
+import com.sangdol.tosspaymock.business.domain.Payment
+import com.sangdol.tosspaymock.business.domain.cancel.Cancellation
+import com.sangdol.tosspaymock.exception.TosspayException
+import com.sangdol.tosspaymock.exception.code.TosspayCancelErrorCode
+import com.sangdol.tosspaymock.infrastructure.persistence.OrderAmountEntity
+import com.sangdol.tosspaymock.infrastructure.persistence.OrderAmountRepository
+import com.sangdol.tosspaymock.web.dto.PaymentCancelRequest
+import com.sangdol.tosspaymock.web.dto.PaymentConfirmRequest
+import com.sangdol.tosspaymock.web.dto.PaymentResponse
+import io.github.oshai.kotlinlogging.KLogger
+import io.github.oshai.kotlinlogging.KotlinLogging
+import org.springframework.stereotype.Service
+
+private val log: KLogger = KotlinLogging.logger {}
+
+@Service
+class TosspayService(
+    private val idGenerator: IDGenerator,
+    private val orderAmountRepository: OrderAmountRepository,
+) {
+
+    fun confirm(request: PaymentConfirmRequest): PaymentResponse {
+        log.info { "[TosspayService.confirm] 결제 확정 시작: paymentKey=${request.paymentKey}, amount=${request.amount}" }
+
+        val payment = choosePayment(request).also { saveAmount(request.paymentKey, it) }
+
+        return payment.toResponse()
+            .also {
+                log.info { "[TosspayService.confirm] 결제 확정 완료: paymentKey=${request.paymentKey}, amount=${request.amount}" }
+            }
+    }
+
+    fun cancel(paymentKey: String, request: PaymentCancelRequest): PaymentResponse {
+        log.info { "[TosspayService.cancel] 결제 취소 시작: paymentKey=${paymentKey}" }
+
+        val orderAmount = orderAmountRepository.findByPaymentKey(paymentKey)
+            ?: throw TosspayException(TosspayCancelErrorCode.NOT_FOUND_PAYMENT)
+
+        val cancellation = Cancellation.random(
+            cancelReason = request.cancelReason,
+            cancelAmount = request.cancelAmount ?: orderAmount.totalAmount(),
+            easyPayDiscountAmount = orderAmount.easypayDiscountAmount,
+            cardDiscountAmount = orderAmount.cardDiscountAmount,
+            transferDiscountAmount = orderAmount.transferDiscountAmount
+        )
+
+        return Payment.randomForCancellation(paymentKey, cancellation)
+            .toResponse()
+            .also {
+                log.info { "[TosspayService.cancel] 결제 취소 완료: paymentKey=${paymentKey}" }
+            }
+    }
+
+    private fun choosePayment(request: PaymentConfirmRequest): Payment {
+        log.info { "[TosspayService.choosePayment] 랜덤 결제 정보 생성 시작: paymentKey=${request.paymentKey}, amount=${request.amount}" }
+        val randomValue = Math.random()
+
+        // 70%는 간편결제에 배정
+        return if (randomValue < 0.7) {
+            // 70%의 간편결제 중 70%는 카드
+            if (randomValue < 0.49) {
+                Payment.randomWithEasypayCard(
+                    request.paymentKey, request.orderId, request.amount, request.requestedAt
+                ).also {
+                    log.info { "[Tosspayment.choosePayment] 간편결제 + 카드 결제 객체 생성 완료" }
+                }
+            } else { // 30%는 간편결제 선불 충전액
+                Payment.randomWithEasypayPrepaid(
+                    request.paymentKey, request.orderId, request.amount, request.requestedAt
+                ).also {
+                    log.info { "[Tosspayment.choosePayment] 간편결제 + 충전식 결제 객체 생성 완료" }
+                }
+            }
+        } else if (randomValue < 0.95) { // 남은 30% 중 25%는 일반 카드
+            Payment.randomWithCard(
+                request.paymentKey, request.orderId, request.amount, request.requestedAt
+            ).also {
+                log.info { "[Tosspayment.choosePayment] 카드 결제 객체 생성 완료" }
+            }
+        } else { // 나머지는 계좌이체
+            Payment.randomWithBankTransfer(
+                request.paymentKey, request.orderId, request.amount, request.requestedAt
+            ).also {
+                log.info { "[Tosspayment.choosePayment] 계좌이체 결제 객체 생성 완료" }
+            }
+        }
+    }
+
+    private fun saveAmount(paymentKey: String, payment: Payment) {
+        log.info { "[Tosspayment.saveAmount] 결제 금액 정보 저장 시작: paymentKey=${paymentKey}" }
+        val easypayDiscountAmount = payment.easyPay?.discountAmount ?: 0
+        val cardDiscountAmount = 0
+        val transferDiscountAmount = 0
+
+        val orderAmount = OrderAmountEntity(
+            idGenerator.create(),
+            paymentKey,
+            (payment.totalAmount - easypayDiscountAmount),
+            easypayDiscountAmount,
+            cardDiscountAmount,
+            transferDiscountAmount
+        )
+
+        orderAmountRepository.save(orderAmount).also {
+            log.info { "[Tosspayment.saveAmount] 결제 금액 정보 저장 완료: id=${it.id}, paymentKey=${paymentKey}, amount=${orderAmount.approvedAmount}, easypayDiscount=${orderAmount.easypayDiscountAmount}" }
+        }
+    }
+}