Link Compatibility

Millions of Firebase links exist in emails, printed materials, and databases. During migration, you need strategies to handle these existing links while transitioning to ULink.

What you'll learn

How ULink maintains compatibility with Firebase link formats
URL redirect strategies for legacy links
Handling edge cases in link migration

The challenge

Firebase links are everywhere:

Marketing emails sent months ago
QR codes on printed packaging
Links in app store descriptions
Database records with link references
Social media posts
Ad campaigns

You can't update all of these instantly. You need a transition strategy.

Key Concept

The goal isn't to immediately replace every Firebase link. It's to ensure existing links keep working while you migrate to ULink for new links.

Compatibility strategies

Option 1: Domain redirect

If you used a custom domain with Firebase, you can redirect it to ULink:

links.yourapp.com (Firebase) → links.yourapp.com (ULink)

How it works:

Keep your custom domain
Update DNS to point to ULink
Import your link slugs to ULink
Existing links start working through ULink

Pros:

Existing links keep working
No updates needed to embedded links
Seamless transition for users

Cons:

Requires custom domain (not page.link)
Links must be imported accurately
Some Firebase-specific parameters may need handling

iOS consideration: Update Associated Domains only after verifying ULink serves the AASA file correctly. Test thoroughly before removing Firebase.

Option 2: Redirect mapping

For Firebase's default domain (page.link), create redirects from Firebase links to ULink equivalents:

yourapp.page.link/summer → links.yourapp.com/summer

Implementation options:

Cloudflare Workers
Custom redirect service
Server-side redirect mapping

Option 3: Redirect from old domains

If you had a custom domain with Firebase, redirect it to ULink:

Old links: links.yourapp.com (was Firebase) → now ULink

Steps:

Set up same domain in ULink
Update DNS to point to ULink
Recreate links with matching slugs
Old URLs now route through ULink

Gotcha

Firebase page.link domains no longer work. If you used Firebase's default domain (yourapp.page.link), those links are now broken. Focus on creating new ULink links and updating your marketing materials.

Parameter mapping

Firebase and ULink use similar but not identical parameters. Here's how they map:

Firebase Parameter	ULink Equivalent
`link`	`fallback_url`
`apn` (Android package)	Configured in project settings
`ibi` (iOS bundle ID)	Configured in project settings
`afl` (Android fallback)	`android_fallback_url`
`ifl` (iOS fallback)	`ios_fallback_url`
`ofl` (Other fallback)	`fallback_url` (used for desktop)
`st` (Social title)	`metadata.ogTitle`
`sd` (Social description)	`metadata.ogDescription`
`si` (Social image)	`metadata.ogImage`

Dynamic parameter translation

If you generate Firebase links dynamically, update your code:

Firebase format:

https://yourapp.page.link/?link=https://app.com/product/123&apn=com.yourapp&ibi=com.yourapp

ULink format:

https://links.yourapp.com/product/123?productId=123

ULink's cleaner format puts routing data in the path while configuration lives in your project settings.

Import/export process

Exporting from Firebase

Go to Firebase Console → Dynamic Links
Download link report (CSV)
Note: Only shows links created in console, not API-generated

For API-generated links

If you created links via Firebase API:

Check your database for stored link references
Review server logs for link creation patterns
Audit marketing platforms for saved links

Importing to ULink

Dashboard creation

Create links manually in the ULink dashboard
Best for small numbers of high-value links

API migration

Script the migration using ULink REST API
Create each link with matching slug
Best for large numbers of links
Validate with spot checks

Key Concept

Focus on preserving the slug (the unique part after the domain). As long as the slug matches and your domain redirects correctly, links will work.

Handling edge cases

Links with complex parameters

Some Firebase links include extensive UTM parameters or custom data. Ensure these pass through:

?utm_source=email&utm_campaign=summer&custom_ref=abc123

ULink preserves query parameters through redirects.

Links in native apps

If other apps link directly to your Firebase URLs, they'll need updates. Reach out to partners with integration timelines.

Cached links

Some platforms cache link metadata. After migration, clear caches:

Facebook Sharing Debugger
Twitter Card Validator
LinkedIn Post Inspector

QR codes

Printed QR codes can't be updated. Options:

Keep redirect in place until replacement
Reprint if high-value
Use redirect service as permanent solution

Quick recap

Domain redirect is cleanest if you have a custom domain
Run parallel systems during transition, but plan for shutdown
Map Firebase parameters to ULink equivalents
Import existing links to preserve slugs
Have a strategy for QR codes and printed materials