Redirect and rewrite rules in Firebase - Step-by-Step Execution

Process Flow - Redirect and rewrite rules

User Request URL

↓

Check Redirect Rules

| No↓

Check Rewrite Rules

| No↓

Serve Original Content

↓

End

When a user requests a URL, Firebase first checks redirect rules to send a redirect response if matched. If no redirect applies, it checks rewrite rules to serve different content without changing the URL. Otherwise, it serves the original content.

Execution Sample

Firebase

redirects:
  - source: /old-page
    destination: /new-page
    type: 301
rewrites:
  - source: /app/**
    destination: /index.html

This config redirects '/old-page' to '/new-page' with a 301 status, and rewrites any '/app/...' URL to serve 'index.html' without changing the URL.

Process Table

Step	User Request URL	Redirect Rule Match?	Redirect Action	Rewrite Rule Match?	Rewrite Action	Final Response
1	/old-page	Yes	Send 301 redirect to /new-page	No	N/A	Redirect to /new-page
2	/app/dashboard	No	N/A	Yes	Serve /index.html content	Serve /index.html content with URL /app/dashboard
3	/about	No	N/A	No	N/A	Serve original /about content
4	/old-page/sub	No	N/A	No	N/A	Serve original /old-page/sub content
5	/app	No	N/A	Yes	Serve /index.html content	Serve /index.html content with URL /app
6	/new-page	No	N/A	No	N/A	Serve original /new-page content
7	/old-page	Yes	Send 301 redirect to /new-page	No	N/A	Redirect to /new-page

💡 Execution stops after sending redirect or serving content based on matched rules.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	After Step 5	After Step 6	After Step 7
User Request URL	-	/old-page	/app/dashboard	/about	/old-page/sub	/app	/new-page	/old-page
Redirect Rule Match	-	Yes	No	No	No	No	No	Yes
Rewrite Rule Match	-	No	Yes	No	No	Yes	No	No
Final Response	-	Redirect to /new-page	Serve /index.html content with URL /app/dashboard	Serve original /about content	Serve original /old-page/sub content	Serve /index.html content with URL /app	Serve original /new-page content	Redirect to /new-page

Key Moments - 3 Insights

Why does a redirect stop further processing of rewrite rules?

Because redirect sends a response back to the browser immediately (see execution_table step 1), so rewrite rules are not checked after a redirect match.

If a URL matches both redirect and rewrite rules, which one applies?

Redirect rules have priority and apply first (see step 1 and 7). Rewrite rules only apply if no redirect matches.

Does a rewrite change the URL shown in the browser?

No, rewrite serves different content internally without changing the URL (see step 2 and 5). The browser URL stays the same.

Visual Quiz - 3 Questions

Look at the execution table, what is the final response at step 3 when the user requests '/about'?

A Redirect to /new-page

B Serve /index.html content

C Serve original /about content

D Serve original /old-page/sub content

💡 Hint

Check the 'Final Response' column in row for step 3.

At which step does the redirect rule match the URL '/old-page'?

A Step 2

B Step 1

C Step 5

D Step 4

💡 Hint

Look at the 'Redirect Rule Match?' column for '/old-page' requests.

If the redirect rule for '/old-page' was removed, what would be the final response at step 1?

A Serve original /old-page content

B Redirect to /new-page

C Serve /index.html content

D Serve original /about content

💡 Hint

Without redirect match, rewrite rules are checked; '/old-page' does not match rewrite rules in the table.

Concept Snapshot

Redirect and rewrite rules in Firebase:
- Redirects send a browser response to change URL.
- Rewrites serve different content without changing URL.
- Redirects checked first; if none match, rewrites apply.
- If no rules match, original content is served.
- Use redirects for URL changes, rewrites for SPA routing.

Full Transcript

When a user requests a URL, Firebase first checks if any redirect rule matches. If yes, it sends a redirect response to the browser, stopping further checks. If no redirect matches, it checks rewrite rules to serve different content internally without changing the URL shown. If no rewrite matches, the original content is served. Redirects have priority over rewrites. Rewrites are useful for single-page apps to serve index.html for many URLs. Redirects change the browser URL, rewrites do not.