Metadata API (static metadata) in NextJS - Step-by-Step Execution

Concept Flow - Metadata API (static metadata)

Define metadata object

↓

Export metadata

↓

Next.js reads metadata at build

↓

Static metadata applied to page

↓

Browser receives page with metadata

This flow shows how you define and export static metadata in Next.js, which Next.js reads at build time to add metadata to the page.

Execution Sample

NextJS

export const metadata = {
  title: 'Home Page',
  description: 'Welcome to our site',
};

export default function Page() {
  return <h1>Hello</h1>;
}

Defines static metadata for a page and exports a simple React component.

Execution Table

Step	Action	Evaluation	Result
1	Read export 'metadata'	metadata object found	{ title: 'Home Page', description: 'Welcome to our site' }
2	Next.js processes metadata at build	Static metadata recognized	Metadata ready to inject in HTML head
3	Render Page component	JSX <h1>Hello</h1>	HTML <h1>Hello</h1> rendered
4	Inject metadata into HTML head	Add <title> and <meta>	<title>Home Page</title> and <meta name="description" content="Welcome to our site"> added
5	Send final HTML to browser	Page with metadata and content	Browser receives page with title and description
6	Exit	All steps complete	Static metadata applied successfully

💡 All metadata processed and page rendered with static metadata

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
metadata	undefined	{ title: 'Home Page', description: 'Welcome to our site' }	{ title: 'Home Page', description: 'Welcome to our site' }	{ title: 'Home Page', description: 'Welcome to our site' }

Key Moments - 2 Insights

Why does Next.js read the metadata object before rendering the page?

Next.js reads the exported metadata object at build time (see Step 2 in execution_table) to generate static HTML with metadata included, improving SEO and performance.

What happens if the metadata object is missing or empty?

If metadata is missing, Next.js will render the page without static metadata tags (no title or description), so SEO benefits are lost (not shown in execution_table but implied).

Visual Quiz - 3 Questions

Look at the execution_table, what is the metadata value after Step 1?

A {}

B undefined

C { title: 'Home Page', description: 'Welcome to our site' }

D null

💡 Hint

Check the 'Result' column in row for Step 1 in execution_table

At which step does Next.js inject the metadata into the HTML head?

A Step 3

B Step 4

C Step 2

D Step 5

💡 Hint

Look for the action mentioning 'Inject metadata into HTML head' in execution_table

If you change the metadata title, which step reflects that change in the execution_table?

A Step 1

B Step 3

C Step 4

D Step 5

💡 Hint

Metadata value is first read and evaluated at Step 1

Concept Snapshot

Next.js static Metadata API:
- Export a 'metadata' object from your page file
- Next.js reads it at build time
- Metadata is injected into HTML head
- Improves SEO and page info
- Works only with static metadata (no runtime changes)

Full Transcript

This visual trace shows how Next.js handles static metadata. First, the metadata object is defined and exported from the page file. Next.js reads this metadata at build time before rendering the page. Then, it injects the metadata into the HTML head, adding the title and description tags. Finally, the page with metadata is sent to the browser. This process ensures metadata is static and improves SEO. If metadata is missing, the page renders without these tags. Changing metadata updates the content at build time only.