diff --git a/leaky-ships/lib/backend/components/checkPasswordIsValid.ts b/leaky-ships/lib/backend/components/checkPasswordIsValid.ts
index 13b4b41..8d0a19d 100644
--- a/leaky-ships/lib/backend/components/checkPasswordIsValid.ts
+++ b/leaky-ships/lib/backend/components/checkPasswordIsValid.ts
@@ -3,8 +3,8 @@ import sendError, { API } from "./sendError"
 import type { Player } from "@prisma/client"
 import bcrypt from "bcrypt"
 
-export default async function checkPasswordIsValid(
-  context: API,
+export default async function checkPasswordIsValid<T>(
+  context: API<T>,
   player: Player,
   password: string,
   next: () => void
diff --git a/leaky-ships/lib/backend/components/checkTokenIsValid.ts b/leaky-ships/lib/backend/components/checkTokenIsValid.ts
index 0f48f6c..ff17140 100644
--- a/leaky-ships/lib/backend/components/checkTokenIsValid.ts
+++ b/leaky-ships/lib/backend/components/checkTokenIsValid.ts
@@ -4,8 +4,8 @@ import type { IdToken, RawToken } from "./createTokenDB"
 import sendError, { API } from "./sendError"
 import jwt from "jsonwebtoken"
 
-async function checkTokenIsValid(
-  context: API,
+async function checkTokenIsValid<T>(
+  context: API<T>,
   rawToken: RawToken,
   next: (token: IdToken) => void
 ) {
diff --git a/leaky-ships/lib/backend/components/getPlayerByIdDB.ts b/leaky-ships/lib/backend/components/getPlayerByIdDB.ts
index d6ebfe0..af84e59 100644
--- a/leaky-ships/lib/backend/components/getPlayerByIdDB.ts
+++ b/leaky-ships/lib/backend/components/getPlayerByIdDB.ts
@@ -3,8 +3,8 @@ import { rejectionErrors } from "../errors"
 import sendError, { API } from "./sendError"
 import type { Player, Token } from "@prisma/client"
 
-export default async function getPlayerByIdDB(
-  context: API,
+export default async function getPlayerByIdDB<T>(
+  context: API<T>,
   tokenDB: Token,
   next: (player: Player) => void
 ) {
diff --git a/leaky-ships/lib/backend/components/getPlayerByNameDB.ts b/leaky-ships/lib/backend/components/getPlayerByNameDB.ts
index b3c3752..a74b35b 100644
--- a/leaky-ships/lib/backend/components/getPlayerByNameDB.ts
+++ b/leaky-ships/lib/backend/components/getPlayerByNameDB.ts
@@ -3,8 +3,8 @@ import { rejectionErrors } from "../errors"
 import sendError, { API } from "./sendError"
 import type { Player } from "@prisma/client"
 
-export default async function getPlayerByNameDB(
-  context: API,
+export default async function getPlayerByNameDB<T>(
+  context: API<T>,
   username: string,
   next: (player: Player) => void
 ) {
diff --git a/leaky-ships/lib/backend/components/getTokenDB.ts b/leaky-ships/lib/backend/components/getTokenDB.ts
index 7dba5a7..7263677 100644
--- a/leaky-ships/lib/backend/components/getTokenDB.ts
+++ b/leaky-ships/lib/backend/components/getTokenDB.ts
@@ -4,8 +4,8 @@ import type { IdToken } from "./createTokenDB"
 import sendError, { API } from "./sendError"
 import type { Token } from "@prisma/client"
 
-async function getTokenDB(
-  context: API,
+async function getTokenDB<T>(
+  context: API<T>,
   token: IdToken,
   next: (tokenDB: Token) => void
 ) {
diff --git a/leaky-ships/lib/backend/components/getTokenFromBody.ts b/leaky-ships/lib/backend/components/getTokenFromBody.ts
index ca75fd3..4ad43f2 100644
--- a/leaky-ships/lib/backend/components/getTokenFromBody.ts
+++ b/leaky-ships/lib/backend/components/getTokenFromBody.ts
@@ -2,8 +2,8 @@ import { rejectionErrorFns } from "../errors"
 import type { RawToken } from "./createTokenDB"
 import sendError, { API } from "./sendError"
 
-async function getTokenFromBody(
-  context: API,
+async function getTokenFromBody<T>(
+  context: API<T>,
   next: (accessToken: RawToken) => void
 ) {
   const type = "ACCESS"
diff --git a/leaky-ships/lib/backend/components/getTokenFromCookie.ts b/leaky-ships/lib/backend/components/getTokenFromCookie.ts
index 325f9fd..62c7337 100644
--- a/leaky-ships/lib/backend/components/getTokenFromCookie.ts
+++ b/leaky-ships/lib/backend/components/getTokenFromCookie.ts
@@ -2,8 +2,8 @@ import createPlayerDB from "./createPlayerDB"
 import createTokenDB, { RawToken } from "./createTokenDB"
 import type { API } from "./sendError"
 
-async function getTokenFromCookie(
-  context: API,
+async function getTokenFromCookie<T>(
+  context: API<T>,
   next: (refreshToken: RawToken) => void
 ) {
   const type = "REFRESH"
diff --git a/leaky-ships/lib/backend/components/getUserFromBody.ts b/leaky-ships/lib/backend/components/getUserFromBody.ts
index 577b1d5..39dace9 100644
--- a/leaky-ships/lib/backend/components/getUserFromBody.ts
+++ b/leaky-ships/lib/backend/components/getUserFromBody.ts
@@ -1,8 +1,8 @@
 import { rejectionErrors } from "../errors"
 import sendError, { API } from "./sendError"
 
-async function getUserFromBody(
-  context: API,
+async function getUserFromBody<T>(
+  context: API<T>,
   next: (username: string, password: string) => void
 ) {
   const body = JSON.parse(context.req.body)
diff --git a/leaky-ships/lib/backend/components/sendError.ts b/leaky-ships/lib/backend/components/sendError.ts
index 7fe8134..ab57ab5 100644
--- a/leaky-ships/lib/backend/components/sendError.ts
+++ b/leaky-ships/lib/backend/components/sendError.ts
@@ -2,12 +2,15 @@ import type { rejectionError } from "../errors"
 import logging from "../logging"
 import type { NextApiRequest, NextApiResponse } from "next"
 
-export interface API {
+export interface API<T> {
   req: NextApiRequest
-  res: NextApiResponse
+  res: NextApiResponse<T>
 }
 
-export default function sendError(context: API, err: rejectionError | Error) {
+export default function sendError<T>(
+  context: API<T>,
+  err: rejectionError | Error
+) {
   const { res, req } = context
   // If something went wrong, let the client know with status 500
   res.status("statusCode" in err ? err.statusCode : 500).end()
diff --git a/leaky-ships/lib/backend/components/sendResponse.ts b/leaky-ships/lib/backend/components/sendResponse.ts
index f6ad848..a884de3 100644
--- a/leaky-ships/lib/backend/components/sendResponse.ts
+++ b/leaky-ships/lib/backend/components/sendResponse.ts
@@ -8,7 +8,7 @@ export interface Result<T> {
   type?: Logging[]
 }
 
-export default function sendResponse<T>(context: API, result: Result<T>) {
+export default function sendResponse<T>(context: API<T>, result: Result<T>) {
   const { req, res } = context
   res.status(result.statusCode ?? 200)
   result.body ? res.json(result.body) : res.end()
diff --git a/leaky-ships/lib/backend/components/updatePlayerDB.ts b/leaky-ships/lib/backend/components/updatePlayerDB.ts
index 60220d0..f870873 100644
--- a/leaky-ships/lib/backend/components/updatePlayerDB.ts
+++ b/leaky-ships/lib/backend/components/updatePlayerDB.ts
@@ -3,8 +3,8 @@ import { rejectionErrors } from "../errors"
 import sendError, { API } from "./sendError"
 import type { Player, Prisma } from "@prisma/client"
 
-async function updatePlayerDB(
-  context: API,
+async function updatePlayerDB<T>(
+  context: API<T>,
   player: Player,
   data: Prisma.PlayerUpdateInput,
   next: (updatedPlayer: Player) => void
diff --git a/leaky-ships/pages/api/user/login.ts b/leaky-ships/pages/api/user/login.ts
index 34046fc..7546478 100644
--- a/leaky-ships/pages/api/user/login.ts
+++ b/leaky-ships/pages/api/user/login.ts
@@ -53,7 +53,7 @@ export default async function login(
   ).catch((err) => sendError(context, err))
 }
 
-async function preCheck(context: API, next: () => void) {
+async function preCheck<T>(context: API<T>, next: () => void) {
   const { req } = context
   const oldRefreshToken = req.cookies.token