Deploying expressjs functions and nextjs monorepo to single site

Support
,
1

I am struggling to setup the config file for a monorepo i am trying to deploy to a single site, i have a nextjs app which acts as my frontend and a expressjs app that runs a variety of server functions for my api, a full tree map is bellow, i tried both seperate netlify.tomls and a shared one shown below but neither seem to load correctly when trying to import my project from git so i am wandering what the correct project structure/netlify.toml is for this situation?

Netlify Toml

[build]
  base = "frontend"
  command = "npm run build"
  publish = ".next"

[functions]
  external_node_modules = ["express"]
  node_bundler = "esbuild"
[[redirects]]
  force = true
  from = "/api/*"
  status = 200
  to = "/.netlify/functions/api/:splat"

Project Tree

.
├── firebase-debug.log
├── firebase.json
├── firestore-debug.log
├── firestore.indexes.json
├── firestore.rules
├── frontend
│   ├── README.md
│   ├── app
│   │   ├── accounts
│   │   │   ├── layout.tsx
│   │   │   ├── oauth
│   │   │   │   └── page.tsx
│   │   │   └── page.tsx
│   │   ├── components
│   │   │   ├── accountCard.tsx
│   │   │   ├── lineChart.tsx
│   │   │   └── transactionsBreakdown.tsx
│   │   ├── dashboard
│   │   │   ├── [id]
│   │   │   │   └── page.tsx
│   │   │   ├── layout.tsx
│   │   │   └── page.tsx
│   │   ├── favicon.ico
│   │   ├── globals.css
│   │   ├── layout.tsx
│   │   ├── nav.tsx
│   │   ├── page.tsx
│   │   └── signin
│   │       └── page.tsx
│   ├── firebase.js
│   ├── middleware.ts
│   ├── netlify.toml
│   ├── next-env.d.ts
│   ├── next.config.js
│   ├── package-lock.json
│   ├── package.json
│   ├── postcss.config.js
│   ├── public
│   │   ├── manifest.json
│   │   ├── next.svg
│   │   ├── service-worker.js
│   │   ├── service-worker.js.LICENSE.txt
│   │   └── vercel.svg
│   ├── service-worker
│   │   ├── index.js
│   │   ├── sw.tsconfig.json
│   │   └── webpack.config.js
│   ├── tailwind.config.ts
│   ├── tsconfig.json
│   └── types
│       ├── api.d.ts
│       └── service-worker.d.ts
├── server
│   ├── dist
│   ├── netlify.toml
│   ├── node_modules
│   ├── package-lock.json
│   ├── package.json
│   ├── serviceKey.json
│   ├── src
│   │   ├── db
│   │   │   └── *.ts
│   │   ├── index.ts
│   │   ├── plaid.ts
│   │   ├── routes
│   │   │   └── *.ts
│   │   └── webhookHandlers
│   └── tsconfig.json
├── tree.txt
└── ui-debug.log
2

Since you’re using Next.js, may I ask why you need Express separately? I thought the whole point of Next.js was to have a single tool that can handle both - API and frontend.