Building Scalable APIs with Node.js and Fastify

Introduction

Fastify is one of the fastest Node.js web frameworks available. In this tutorial, we'll build a scalable REST API from scratch.

Setting Up the Project

Bash

mkdir my-api && cd my-api
npm init -y
npm install fastify @fastify/cors
npm install -D typescript @types/node

Creating the Server

Text

# Builder stage
FROM node:24-alpine AS builder

# Build dependencies
RUN apk update && apk add --no-cache python3 build-base git
RUN corepack enable && corepack prepare pnpm@10.6.5 --activate

WORKDIR /app

# Faster, reproducible installs
RUN pnpm config set store-dir /root/.pnpm-store && pnpm config set prefer-frozen-lockfile true

COPY package.json pnpm-lock.yaml ./
COPY .npmrc* .pnpmfile.cjs* ./

RUN pnpm install --frozen-lockfile

COPY . .

RUN pnpm build

# Production stage
FROM node:24-alpine AS production

RUN addgroup -g 1001 nodejs && adduser -S -u 1001 -G nodejs api
RUN corepack enable && corepack prepare pnpm@10.6.5 --activate

# Runtime deps: ffmpeg + yt-dlp prerequisites
RUN apk update && apk add --no-cache ffmpeg python3 py3-pip ca-certificates curl
RUN pip3 install --break-system-packages --no-cache-dir "yt-dlp[default]" bgutil-ytdlp-pot-provider

WORKDIR /app

ENV NODE_ENV=production CI=false

COPY .npmrc* .pnpmfile.cjs* ./
COPY package.json pnpm-lock.yaml ./

RUN pnpm config set store-dir /root/.pnpm-store && \
    pnpm config set prefer-frozen-lockfile true && \
    pnpm install --frozen-lockfile --prod && \
    pnpm store prune && \
    npm cache clean --force && \
    rm -rf /root/.npm /root/.pnpm-store /tmp/*

COPY --from=builder /app/dist ./dist
COPY --from=builder /app/src/views ./src/views
COPY --from=builder /app/drizzle.config.ts ./drizzle.config.ts
COPY --from=builder /app/src/db/migrations ./src/db/migrations

RUN mkdir -p /app/uploads /uploads && \
    chown -R api:nodejs /app/uploads /uploads && \
    chmod -R 775 /app/uploads /uploads && \
    chown -R api:nodejs /app

USER api

EXPOSE 6795

HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:6795/health || exit 1

CMD ["pnpm", "start:prod"]

Adding Routes and Validation

Fastify uses JSON Schema for request validation, making it both fast and type-safe.

Conclusion

Fastify provides an excellent foundation for building production-ready APIs.