diff --git a/packages/medusa/src/services/__tests__/custom-shipping-option.js b/packages/medusa/src/services/__tests__/custom-shipping-option.js
index a4a8d31cfb..6536495501 100644
--- a/packages/medusa/src/services/__tests__/custom-shipping-option.js
+++ b/packages/medusa/src/services/__tests__/custom-shipping-option.js
@@ -4,7 +4,7 @@ import { MockManager, MockRepository, IdMap } from "medusa-test-utils"
 describe("CustomShippingOptionService", () => {
   describe("list", () => {
     const customShippingOptionRepository = MockRepository({
-      find: q => {
+      find: (q) => {
         return Promise.resolve([
           {
             id: "cso-test",
@@ -44,7 +44,7 @@ describe("CustomShippingOptionService", () => {
 
   describe("retrieve", () => {
     const customShippingOptionRepository = MockRepository({
-      findOne: q => {
+      findOne: (q) => {
         if (q.where.id === "cso-test") {
           return Promise.resolve({
             id: "cso-test",
@@ -88,8 +88,8 @@ describe("CustomShippingOptionService", () => {
     const customShippingOptionRepository = MockRepository({
       create: jest
         .fn()
-        .mockImplementation(f => Promise.resolve({ id: "test-cso", ...f })),
-      save: jest.fn().mockImplementation(f => Promise.resolve(f)),
+        .mockImplementation((f) => Promise.resolve({ id: "test-cso", ...f })),
+      save: jest.fn().mockImplementation((f) => Promise.resolve(f)),
     })
 
     const customShippingOptionService = new CustomShippingOptionService({
@@ -114,7 +114,7 @@ describe("CustomShippingOptionService", () => {
         cart_id: "test-cso-cart",
         shipping_option_id: "test-so",
         price: 30,
-        metadata: {},
+        metadata: undefined,
       })
 
       expect(customShippingOptionRepository.save).toHaveBeenCalledTimes(1)
@@ -123,7 +123,7 @@ describe("CustomShippingOptionService", () => {
         cart_id: "test-cso-cart",
         shipping_option_id: "test-so",
         price: 30,
-        metadata: {},
+        metadata: undefined,
       })
     })
   })
diff --git a/packages/medusa/src/services/custom-shipping-option.js b/packages/medusa/src/services/custom-shipping-option.js
deleted file mode 100644
index e45c86331e..0000000000
--- a/packages/medusa/src/services/custom-shipping-option.js
+++ /dev/null
@@ -1,111 +0,0 @@
-import { MedusaError } from "medusa-core-utils"
-import { BaseService } from "medusa-interfaces"
-
-class CustomShippingOptionService extends BaseService {
-  constructor({ manager, customShippingOptionRepository }) {
-    super()
-
-    /** @private @const {EntityManager} */
-    this.manager_ = manager
-
-    /** @private @const {CustomShippingOptionRepository} */
-    this.customShippingOptionRepository_ = customShippingOptionRepository
-  }
-
-  /**
-   * Sets the service's manager to a given transaction manager
-   * @param {EntityManager} manager - the manager to use
-   * @return {CustomShippingOptionService} a cloned CustomShippingOption service
-   */
-  withTransaction(manager) {
-    if (!manager) {
-      return this
-    }
-
-    const cloned = new CustomShippingOptionService({
-      manager,
-      customShippingOptionRepository: this.customShippingOptionRepository_,
-    })
-
-    cloned.transactionManager_ = manager
-    return cloned
-  }
-
-  /**
-   * Retrieves a specific shipping option.
-   * @param {string} id - the id of the custom shipping option to retrieve.
-   * @param {*} config - any options needed to query for the result.
-   * @return {Promise<CustomShippingOption>} which resolves to the requested custom shipping option.
-   */
-  async retrieve(id, config = {}) {
-    const customShippingOptionRepo = this.manager_.getCustomRepository(
-      this.customShippingOptionRepository_
-    )
-
-    const validatedId = this.validateId_(id)
-    const query = this.buildQuery_({ id: validatedId }, config)
-
-    const customShippingOption = await customShippingOptionRepo.findOne(query)
-
-    if (!customShippingOption) {
-      throw new MedusaError(
-        MedusaError.Types.NOT_FOUND,
-        `Custom shipping option with id: ${id} was not found.`
-      )
-    }
-
-    return customShippingOption
-  }
-
-  /** Fetches all custom shipping options related to the given selector
-   * @param {Object} selector - the query object for find
-   * @param {Object} config - the configuration used to find the objects. contains relations, skip, and take.
-   * @return {Promise<CustomShippingOption[]>} custom shipping options matching the query
-   */
-  async list(
-    selector,
-    config = {
-      skip: 0,
-      take: 50,
-      relations: [],
-    }
-  ) {
-    const customShippingOptionRepo = this.manager_.getCustomRepository(
-      this.customShippingOptionRepository_
-    )
-
-    const query = this.buildQuery_(selector, config)
-
-    return customShippingOptionRepo.find(query)
-  }
-
-  /**
-   * Creates a custom shipping option associated with a given author
-   * @param {object} data - the custom shipping option to create
-   * @param {*} config - any configurations if needed, including meta data
-   * @return {Promise<CustomShippingOption>} resolves to the creation result
-   */
-  async create(data, config = { metadata: {} }) {
-    const { metadata } = config
-
-    const { cart_id, shipping_option_id, price } = data
-
-    return this.atomicPhase_(async (manager) => {
-      const customShippingOptionRepo = manager.getCustomRepository(
-        this.customShippingOptionRepository_
-      )
-
-      const customShippingOption = await customShippingOptionRepo.create({
-        cart_id,
-        shipping_option_id,
-        price,
-        metadata,
-      })
-      const result = await customShippingOptionRepo.save(customShippingOption)
-
-      return result
-    })
-  }
-}
-
-export default CustomShippingOptionService
diff --git a/packages/medusa/src/services/custom-shipping-option.ts b/packages/medusa/src/services/custom-shipping-option.ts
new file mode 100644
index 0000000000..3c437b62e3
--- /dev/null
+++ b/packages/medusa/src/services/custom-shipping-option.ts
@@ -0,0 +1,111 @@
+import { MedusaError } from "medusa-core-utils"
+import { EntityManager } from "typeorm"
+import { TransactionBaseService } from "../interfaces"
+import { CustomShippingOption } from "../models"
+import { CustomShippingOptionRepository } from "../repositories/custom-shipping-option"
+import { FindConfig, Selector } from "../types/common"
+import { CreateCustomShippingOptionInput } from "../types/shipping-options"
+import { buildQuery } from "../utils"
+
+type InjectedDependencies = {
+  manager: EntityManager
+  customShippingOptionRepository: typeof CustomShippingOptionRepository
+}
+class CustomShippingOptionService extends TransactionBaseService<CustomShippingOptionService> {
+  protected manager_: EntityManager
+  protected transactionManager_: EntityManager | undefined
+  protected customShippingOptionRepository_: typeof CustomShippingOptionRepository
+
+  constructor({
+    manager,
+    customShippingOptionRepository,
+  }: InjectedDependencies) {
+    // eslint-disable-next-line prefer-rest-params
+    super(arguments[0])
+
+    this.manager_ = manager
+    this.customShippingOptionRepository_ = customShippingOptionRepository
+  }
+
+  /**
+   * Retrieves a specific shipping option.
+   * @param id - the id of the custom shipping option to retrieve.
+   * @param config - any options needed to query for the result.
+   * @return the requested custom shipping option.
+   */
+  async retrieve(
+    id: string,
+    config: FindConfig<CustomShippingOption> = {}
+  ): Promise<CustomShippingOption> {
+    return await this.atomicPhase_(async (manager) => {
+      const customShippingOptionRepo = manager.getCustomRepository(
+        this.customShippingOptionRepository_
+      )
+
+      const query = buildQuery({ id }, config)
+
+      const customShippingOption = await customShippingOptionRepo.findOne(query)
+
+      if (!customShippingOption) {
+        throw new MedusaError(
+          MedusaError.Types.NOT_FOUND,
+          `Custom shipping option with id: ${id} was not found.`
+        )
+      }
+
+      return customShippingOption
+    })
+  }
+
+  /** Fetches all custom shipping options based on the given selector
+   * @param selector - the query object for find
+   * @param config - the configuration used to find the objects. contains relations, skip, and take.
+   * @return custom shipping options matching the query
+   */
+  async list(
+    selector: Selector<CustomShippingOption>,
+    config: FindConfig<CustomShippingOption> = {
+      skip: 0,
+      take: 50,
+      relations: [],
+    }
+  ): Promise<CustomShippingOption[]> {
+    return await this.atomicPhase_(async (manager) => {
+      const customShippingOptionRepo = manager.getCustomRepository(
+        this.customShippingOptionRepository_
+      )
+
+      const query = buildQuery(selector, config)
+
+      return await customShippingOptionRepo.find(query)
+    })
+  }
+
+  /**
+   * Creates a custom shipping option
+   * @param data - the custom shipping option to create
+   * @param config - any configurations if needed, including meta data
+   * @return resolves to the creation result
+   */
+  async create(
+    data: CreateCustomShippingOptionInput
+  ): Promise<CustomShippingOption> {
+    const { cart_id, shipping_option_id, price, metadata } = data
+
+    return await this.atomicPhase_(async (manager) => {
+      const customShippingOptionRepo = manager.getCustomRepository(
+        this.customShippingOptionRepository_
+      )
+
+      const customShippingOption = await customShippingOptionRepo.create({
+        cart_id,
+        shipping_option_id,
+        price,
+        metadata,
+      })
+      return await customShippingOptionRepo.save(customShippingOption)
+    })
+  }
+}
+
+export default CustomShippingOptionService
diff --git a/packages/medusa/src/types/shipping-options.ts b/packages/medusa/src/types/shipping-options.ts
index ebf75019f9..4b03a84168 100644
--- a/packages/medusa/src/types/shipping-options.ts
+++ b/packages/medusa/src/types/shipping-options.ts
@@ -52,6 +52,13 @@ export type CreateShippingOptionInput = {
   requirements?: ShippingOptionRequirement[]
 }
 
+export type CreateCustomShippingOptionInput = {
+  price: number
+  shipping_option_id: string
+  cart_id?: string
+  metadata?: Record<string, unknown>
+}
+
 export type UpdateShippingOptionInput = {
   metadata?: Record<string, unknown>
   price_type?: ShippingOptionPriceType