What is Static Site Generation (SSG)

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In the early web, nearly every site was static: hand-written HTML, CSS, maybe a little JavaScript. Over time, the demand for dynamic content (user dashboards, content management systems, comments, etc.) led to server-side rendering (SSR) paradigms, with CGI, PHP, Ruby on Rails, JSP, ASP, and so on.

Then something interesting happened: with the rise of Jamstack thinking and performance optimization becoming a first-class concern, developers began reconsidering — “Why not pre-render what we can, and only use server logic when necessary?” Static Site Generation (SSG) emerged (or re-emerged) as a middle ground: pre-render pages at build time, serve them as static files, but still allow interactive or dynamic parts via client-side APIs or hydration.

Over the last decade, SSGs like Jekyll (launched 2008) popularized the model, especially in the blogging and documentation space. Newer frameworks (Hugo, Eleventy, Gatsby, Next.js with static export, Astro, etc.) further refined the developer experience, performance trade-offs, and hybrid models.

Understanding that lineage helps you see SSG not as a fad but as a refined architectural choice—one that trades runtime complexity for build-time cost and performance.

What is Static Site Generation (SSG)?

At its core, SSG is the process of pre-rendering web pages into static HTML, CSS, and JavaScript files at build time, before any request comes in.

Here’s the canonical workflow:

You author content (Markdown, MDX, JSON, headless CMS sources, etc.).
A build tool gathers that content, combines it with templates or components, and outputs a folder of static files (HTML, CSS, JS, images, assets).
These files are deployed (often on a CDN or static host).
When users request a page, they get pre-generated HTML directly—no server-side rendering at request time.

To illustrate:

flowchart LR
  A["Write content / templates"] --> B["Run SSG build"]
  B --> C["Generate static files (HTML, CSS, JS, assets)"]
  C --> D["Deploy to CDN or static host"]
  E["User HTTP request"] --> F["Serve matching static file from CDN or host"]
  D -.-> F

This pipeline separates “render time” from “request time.” Everything heavy (data fetching, templating, transformations) happens before the site is live.

Key characteristics

All users see the same content at a given route (unless client-side changes override).
The content is “frozen” at build time; changes require a rebuild & redeploy.
You can mix in client-side JavaScript or interactive features (via hydration, islands architecture, etc.), but the base page is static.
Because you’re serving only static files, you can host on cheap, scalable infrastructure (CDNs, blob storage, static hosts).

Advantages and trade-offs

Benefits

Performance / speed. Since HTML is pre-rendered, users receive content immediately (Time to First Byte is minimal).
Scalability. Static files scale trivially—high traffic is handled by caching, CDNs, or globally distributed storage.
Lower infrastructure cost. You don’t need servers executing logic on each request; you only need storage + bandwidth.
Security. No database or server-side logic reduces the attack surface (no SQL injection, fewer runtime vulnerabilities).
Simplicity of deployment. You deploy static assets. There’s no middleware, no server processes to manage or scale.

Trade-offs and challenges

Build time / scalability of builds. As the number of pages grows (thousands), builds can become slow and resource-intensive.
Stale content / rebuilds needed. Any content change requires regenerating pages. For frequently changing content, this becomes burdensome.
Dynamic or personalized content limitations. User-specific data or real-time content is harder to integrate purely in SSG; it often requires client-side APIs or hybrid strategies.
Complexity of client-side hydration. If you sprinkle in interactive components, you must carefully manage hydration so you don’t end up shipping excessive JavaScript.
Search, forms, and user-generated content. Things like full-text search, comments, or forms require extra work (search indexing off-line, serverless functions, third-party services).

Thus, SSG is ideal when the majority of content is stable—documentation, blogs, marketing pages—but becomes more awkward when most of your site is dynamic or user-specific.

SSG vs SSR and hybrid approaches

To understand SSG in context, you also need to compare it with server-side rendering (SSR) and hybrid or incremental strategies.

SSR renders the HTML at runtime (on each request). That means each HTTP call triggers server logic, database queries, templating, etc. SSR works well when content must always be fresh or personalized. But it incurs server cost, latency, and complexity.
Hybrid / incremental static regeneration (ISR) or revalidation models attempt to combine the benefits of SSG and SSR: you pre-build most pages, but allow respawning or refreshing some pages periodically (or on-demand) without full rebuilds.

In practice, many modern frameworks let you adopt mixed rendering: use SSG for content pages, SSR for dynamic parts, or apply incremental updates. The key is to think carefully about which pages really need on-the-fly rendering, then default to SSG for everything else.

What you need to know as a web developer

When to choose SSG

Your site is mostly content (blog, docs, landing pages).
Content updates are batched or infrequent (not every few seconds).
You value performance, SEO, low cost, and simplicity.
You are comfortable with rebuild-based workflows or can automate rebuilds.

If, on the other hand, your site is highly dynamic, personalized, or real-time, SSG alone might not suffice. But even then, hybrid strategies can salvage many benefits.

What to pay attention to in implementation

Pagination and dynamic routes: If you have thousands of pages (e.g. blog archives), generating every page individually may lead to slow builds. Use incremental builds or route partitioning.
Hydration and JavaScript budget: Only hydrate interactive parts. Use frameworks or patterns that allow “islands” or partial hydration.
Incremental updates / partial rebuilds: Use tools or platforms that support incremental builds or revalidation to avoid full rebuilds.
Asset optimization: Minify CSS and JS, lazy load images, bundle/shake unused assets—so your static footprint remains lean.
Caching and CDN strategy: Use proper cache headers, versioned filenames, and edge caching so that users always get fresh content without sacrificing speed.
Build infrastructure: For large sites, local builds may not scale. Consider CI pipelines, build servers, distributed builds.
Fallback for unavailable routes: Some frameworks let you specify fallback behavior for routes not generated ahead of time.

Example code: simple static generation

Below is a minimal example (in a conceptual framework) of generating static pages from Markdown for blog posts:

// pseudo-code: build script

import fs from 'fs';
import path from 'path';
import { compileTemplate } from './templating';

const postsDir = './content/posts';
const outDir = './public';

const markdownToHtml = (md) => {
  // your favorite Markdown → HTML converter
};

for (const filename of fs.readdirSync(postsDir)) {
  if (!filename.endsWith('.md')) continue;
  const slug = path.basename(filename, '.md');
  const md = fs.readFileSync(path.join(postsDir, filename), 'utf8');
  const html = markdownToHtml(md);
  const page = compileTemplate({
    title: /* parse frontmatter title */,
    body: html
  });
  fs.writeFileSync(path.join(outDir, slug + '.html'), page);
}

// pseudo-code: build script

import fs from 'fs';
import path from 'path';
import { compileTemplate } from './templating';

const postsDir = './content/posts';
const outDir = './public';

const markdownToHtml = (md) => {
  // your favorite Markdown → HTML converter
};

for (const filename of fs.readdirSync(postsDir)) {
  if (!filename.endsWith('.md')) continue;
  const slug = path.basename(filename, '.md');
  const md = fs.readFileSync(path.join(postsDir, filename), 'utf8');
  const html = markdownToHtml(md);
  const page = compileTemplate({
    title: /* parse frontmatter title */,
    body: html
  });
  fs.writeFileSync(path.join(outDir, slug + '.html'), page);
}

When you run that script, you’ll get a folder of HTML files ready to be deployed.

Many real frameworks build on this core idea, but introduce template engines, incremental building, dynamic route generators, and more.

Wrap-up and outlook

SSG is no longer a niche approach—it’s a mature and powerful pattern in modern web architecture. By shifting rendering to build time, it gives you top-tier performance, lower costs, and simpler deployments. But it also demands you manage build complexity, content staleness, and hybrid needs for interactivity.

You’ll want to adopt SSG where content is stable, but remain ready to layer in SSR or revalidation for parts that need freshness or personalization. As you saw earlier, the trade-off isn’t binary: you can mix and match approaches depending on needs.

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