Setting external modules on n8n's Code node

You can use most npm libraries on n8n's Code node.

Introduction

n8n is a powerful workflow automation tool. By default, it comes with many built-in nodes and functions. However, sometimes you may want to use external npm packages to extend its functionality. In this post, I'll show you how to do that in a few simple steps.

Why use external modules?

• Access libraries that are not included by default
• Simplify complex logic with well-tested libraries
• Reuse the same codes you already use in your Node.js projects

Step 1: Fork n8n-docker-caddy & setting overrides

However n8n can support external modules, I don't recommend modifying the files directly in your instance, so fork the n8n-docker-caddy and manage your settings in your repository.

1. Fork Repository
2. Setting up custom domain
3. Add npm install in Dockerfile
4. Setting up environment variables in docker compose config)

I created a Github repository that's already set up for customization. My forked repository

cat overrides/Caddyfile.local

# Replace <domain>.<suffix>
n8n.<domain>.<suffix> {
    reverse_proxy n8n:5678 {
      flush_interval -1
    }
}

cat overrides/Dockerfile.n8n-custom

ARG N8N_TAG=1.111.0
FROM docker.n8n.io/n8nio/n8n:${N8N_TAG}
USER root
# install libraries you want
RUN npm explore -g n8n -- npm i --omit=dev yahoo-finance2 && npm cache clean --force
USER node

cat overrides/docker-compose.override.yml
services:
  n8n:
    build:
      context: ./overrides
      dockerfile: Dockerfile.n8n-custom
      args:
        N8N_TAG: ${N8N_TAG:-1.111.0}
    environment:
      # Setting up here
      - N8N_ENABLE_EXTERNAL_MODULES=true
      - NODE_FUNCTION_ALLOW_EXTERNAL=yahoo-finance2
  caddy:
    volumes:
      - ./overrides/Caddyfile.local:/etc/caddy/Caddyfile:ro

Step 2: Setting in several files your instance

git clone https://github.com/<your-org>/n8n-docker-caddy.git
cd n8n-docker-caddy
sudo docker volume create caddy_data
sudo docker volume create n8n_data
vim .env
vim overrides/Caddyfile.local
sudo docker compose up -d

Step 3: Testing on n8n

Once the module is installed, you can import and use it inside a Code node. Here's an example that fetches the current stock chart with yahoo-finance2.

const yf = require("yahoo-finance2").default;

const ticker = query.ticker;
if (!ticker) {
  throw new Error("ticker is required");
}

const period = query.period || "1y";
const interval = query.interval || "1d";
const columns = query.columns || [];
const limit = Number(query.limit ?? 0);

function computePeriod1(periodStr) {
  const now = Date.now();
  const ONE_DAY = 24 * 60 * 60 * 1000;
  const m = {
    "1mo": 30,
    "3mo": 90,
    "6mo": 182,
    "9mo": 273,
    "1y": 365,
    "2y": 730,
    "5y": 1826,
  };
  if (!periodStr || periodStr === "max") return new Date(0);
  if (periodStr === "ytd") {
    const d = new Date();
    return new Date(d.getFullYear(), 0, 1);
  }
  if (m[periodStr]) return new Date(now - m[periodStr] * ONE_DAY);
  const dt = new Date(periodStr);
  if (!isNaN(dt)) return dt;
  return new Date(now - 365 * ONE_DAY);
}

function filterColumns(row, columns) {
  if (!Array.isArray(columns) || columns.length === 0) return row;
  const out = {};
  for (const c of columns) {
    if (c in row) out[c] = row[c];
  }
  return out;
}

const period1 = computePeriod1(period);
const period2 = new Date();

const res = await yf.chart(ticker, {
  period1,
  period2,
  interval,
});

let rows = (res.quotes || []).map((q) => {
  return { ...q, date: q.date instanceof Date ? q.date.toISOString() : q.date };
});

if (limit > 0 && rows.length > limit) {
  rows = rows.slice(-limit);
}

rows = rows.map((r) => filterColumns(r, columns));

return JSON.stringify({
  ticker,
  period,
  interval,
  rows,
});

Updating n8n container

Just pull and up the n8n container.

Switch from the official repo to your fork(origin/upstream setup)

If you already cloned the official repo, switch origin from upstream to your forked repo. You should keep your changes isolated on a dedicated branch (e.g., custom/main). This keeps upstream clean while giving you full control over dependencies.

# stash your upstream's change
git stash
git remote rename origin upstream
git remote add origin https://github.com/<your-org>/n8n-docker-caddy.git
git remote -v
git fetch origin --tags
git checkout -b custom/main origin/custom/main
# Now update your configs

Conclusion

By managing n8n with a forked repository and enabling external modules, you can safety extend your workflows with npm libraries. Start small with one library, and you'll quickly see how much more powerful your automation can become.