UTM Tracking for Branch: How to Build and Validate Campaign Links

Why Branch deep links need separate UTM parameters for GA4

Branch and GA4 measure different things at different levels of the user journey. Branch measures deep link attribution: which campaigns, channels, and creatives drove link clicks that led to app opens, installs, and in-app conversion events — tracked using the Branch SDK installed in the app. GA4 measures web session behavior: what users do on web pages and landing pages that serve as destinations when the app path is unavailable. The two systems intersect whenever a Branch link routes traffic to a web URL — the $fallback_url — rather than directly into the app.

Branch's attribution parameters use a tilde prefix convention: ~channel, ~campaign, ~feature, ~ad_name, ~ad_set_name. These parameters are embedded in the Branch link URL and are parsed by the Branch SDK in the app after link open. They do not get forwarded to the $fallback_url web destination — and even if they were forwarded, GA4 does not understand Branch's tilde-parameter format for channel grouping or campaign attribution. GA4 only reads standard utm_source, utm_medium, and utm_campaign parameters from the query string of the URL that opens in the browser.

The result: teams using Branch for deep linking see a persistent Direct traffic problem in GA4. Paid social campaigns that successfully drive clicks on Branch links show zero attribution in GA4 for the web sessions that result from users landing on the $fallback_url. Email campaigns with Branch links for web-to-app routing show email traffic as Direct. The fix is to build UTM-tagged destination URLs for the $fallback_url in every Branch link.

Branch also offers native UTM parameter support: you can add utm_source, utm_medium, and utm_campaign directly to Branch links, and Branch will forward these to the $fallback_url destination. However, managing this via the Branch dashboard for every link at scale is manual and error-prone. Building programmatically with mlz build and validating with mlz check ensures consistent, validated UTM parameters on every fallback URL before the campaign launches.

Building tracked Branch destination URLs with mlz build

In a Branch link, the $fallback_url parameter specifies the web destination for users on desktop or devices where the app redirect is not possible. This is where UTM parameters belong. Build your tracked destination URL with mlz build before creating or updating the Branch link, then set the resulting tracked_url as the $fallback_url value. Add --validate to confirm the destination resolves correctly and the redirect chain preserves UTM parameters. After configuring the Branch link, run mlz check on the full Branch link URL to verify end-to-end UTM preservation.

# Social campaign (Facebook ad → Branch link → web fallback)
$ mlz build \
  --url "https://example.com/promo" \
  --source "branch" \
  --medium "paid-social" \
  --campaign "summer-launch-jun-2026" \
  --validate

{
  "tracked_url": "https://example.com/promo?utm_source=branch&utm_medium=paid-social&utm_campaign=summer-launch-jun-2026",
  "params": {
    "utm_source": "branch",
    "utm_medium": "paid-social",
    "utm_campaign": "summer-launch-jun-2026"
  },
  "stored": true
}

# Email campaign (Branch link for app re-engagement, web fallback for non-app users)
$ mlz build \
  --url "https://example.com/offer" \
  --source "branch" \
  --medium "email" \
  --campaign "reengagement-email-jun-2026" \
  --content "hero-cta" \
  --validate

{
  "tracked_url": "https://example.com/offer?utm_source=branch&utm_medium=email&utm_campaign=reengagement-email-jun-2026&utm_content=hero-cta"
}

# Organic referral / share (Branch Journeys web banner)
$ mlz build \
  --url "https://example.com/download" \
  --source "branch" \
  --medium "referral" \
  --campaign "journeys-banner-jun-2026" \
  --validate

{
  "tracked_url": "https://example.com/download?utm_source=branch&utm_medium=referral&utm_campaign=journeys-banner-jun-2026"
}

Set the tracked_url as the $fallback_url parameter when creating the Branch link — either in the Branch dashboard, via the Branch API, or in the Branch SDK link creation call. When Branch routes a user to the web fallback (desktop, or mobile without the app installed), the browser opens the tracked URL with UTM parameters intact. GA4 reads those parameters and attributes the web session correctly.

Validating UTM parameters survive the Branch redirect chain

Branch links route clicks through Branch's click-recording infrastructure before deciding where to redirect the user. The routing logic evaluates device type, whether the app is installed, and the Branch link configuration to choose between in-app routing, App Store redirect, or web fallback. Each hop in this chain is an opportunity for query parameters to be dropped — particularly if the $fallback_url value is not correctly encoded within the Branch link URL, or if an intermediate server in your destination stack strips query strings during the redirect.

After setting your tracked fallback URL in the Branch link, validate the complete Branch link URL to confirm UTM parameters survive the redirect chain to the final destination.

# Check the full Branch link URL (not just the fallback destination)
# Confirms UTM parameters survive Branch routing to the final web URL
$ mlz check "https://yourapp.app.link/aBcD1234?%24fallback_url=https%3A%2F%2Fexample.com%2Fpromo%3Futm_source%3Dbranch%26utm_medium%3Dpaid-social%26utm_campaign%3Dsummer-launch-jun-2026"

{
  "url": "https://yourapp.app.link/aBcD1234?%24fallback_url=...",
  "valid": true,
  "checks": [
    { "check": "ssl", "status": "pass", "message": "URL uses HTTPS." },
    { "check": "resolution", "status": "pass", "message": "Destination responded with 200." },
    { "check": "redirects", "status": "pass", "message": "3 redirects detected. UTM parameters present at final destination." }
  ],
  "status_code": 200
}

Note that Branch link redirects often involve more hops than MMP redirects from other platforms — Branch routing may go through Branch's click-recording server, then Branch's routing decision server, then the final fallback URL. This makes the mlz check redirect chain validation especially important for Branch links. If UTM parameters are stripped, check the URL encoding of the $fallback_url parameter (note: Branch uses the dollar-sign prefix $fallback_url which also needs encoding as %24fallback_url in URL query strings). See the redirect UTM stripping guide for diagnosis steps.

Branch UTM tracking gotchas

Branch's tilde-prefixed parameters (~channel, ~campaign) are not UTM parameters and are not read by GA4

Branch uses a tilde prefix to distinguish its own analytics parameters from other query parameters. The ~channel, ~campaign, ~feature, ~ad_name, ~ad_set_name, and ~tags parameters are read by the Branch SDK after the app is opened via the deep link — they power Branch's attribution dashboard and analytics. GA4 ignores Branch's tilde-parameter format. Only standard utm_source, utm_medium, and utm_campaign query string parameters in the URL that opens in the web browser affect GA4 channel grouping and campaign attribution. You need both: Branch parameters for deep link attribution, UTM parameters on the $fallback_url for web session attribution in GA4.

Branch's $desktop_url and $fallback_url serve different routing scenarios — both need UTM parameters

Branch supports multiple web destination parameters for different routing scenarios: $fallback_url (catch-all for unsupported devices and desktop), $desktop_url (specific destination for desktop users), $ios_url and $android_url (App Store and Play Store for users without the app). If you configure both $desktop_url and $fallback_url, you need UTM parameters on both destination URLs — desktop users are routed to $desktop_url, and other unsupported devices use $fallback_url. Generate separate tracked URLs for each destination with mlz build and validate each one with mlz check independently.

Branch Journeys (web-to-app banners) create Branch links from your existing web pages — the page URL needs UTM parameters

Branch Journeys shows a smart banner or interstitial on your mobile website, prompting users to open the app or download it. When a user clicks the Journey CTA, Branch creates a deep link using the current page's URL as the web context. The UTM parameters that matter here are those on the original page URL that showed the Journey banner — not just on the Journey link itself. If a user arrives at https://example.com/promo from a paid social campaign (with UTM parameters) and then clicks the Journey banner, Branch captures that page's UTM parameters as part of the deep link context. Ensure your web pages have UTM parameters from upstream traffic sources — the same pages you serve Branch Journeys on should have UTM-tagged inbound links. Use mlz build to generate tracked URLs for those upstream links.

The $fallback_url parameter name uses a dollar sign prefix that requires URL encoding

When constructing Branch link URLs programmatically or in query strings, the $fallback_url parameter name must be URL-encoded as %24fallback_url because the dollar sign ($) is a reserved character in URL syntax. Additionally, the destination URL value (your tracked URL with UTM parameters) must itself be URL-encoded within the Branch link query string, with & encoded as %26. After constructing the Branch link URL, run mlz check on the complete URL to verify that both the parameter name encoding and the destination URL encoding are correct and that UTM parameters arrive at the final destination.

Branch Universal Ads (Branch-managed ad campaigns) generate Branch links automatically — verify UTM parameters are in the web fallback

If you use Branch Universal Ads to run paid campaigns directly through Branch's ad network integrations (Facebook, Google, TikTok), Branch generates the OneLink or Branch link for you. In this case, check the Branch Universal Ads configuration for each campaign to confirm the web fallback URL ($fallback_url or $desktop_url) includes your UTM parameters. If Branch is auto-generating fallback URLs from your campaign configuration, you may need to add UTM parameters as a custom $fallback_url override in the Branch Universal Ads settings. Use mlz build to generate the correct tracked URL and add it as the custom web fallback in the Branch Universal Ads campaign settings.

Branch UTM naming conventions

Recommended UTM parameter values for Branch campaigns, aligned with GA4 channel reporting and a lowercase-hyphenated taxonomy:

• utm_source: branch for all campaigns where Branch is the deep linking platform. Some teams prefer to use the underlying ad network or channel name (facebook, email, sms) as the UTM source to match GA4 channel groupings more directly. Using branch as the source groups all Branch-linked web sessions together in GA4, making it easy to see the total web traffic footprint of Branch campaigns before drilling into medium and campaign. Using the channel name aligns GA4's automatic channel grouping more precisely (e.g., GA4 recognizes utm_source=facebook and utm_medium=paid-social as "Paid Social" in channel grouping). Choose one convention and apply it consistently across all Branch links.
• utm_medium: Use the channel type of the campaign, aligned with GA4 default channel groupings. For paid social (Meta, TikTok): paid-social. For email re-engagement campaigns: email. For SMS campaigns: sms. For push notification campaigns using Branch for deep linking: push. For referral links (user-generated shares, referral programs): referral. For Branch Journeys (web-to-app banners): referral or web-to-app. For organic app store optimization or QR codes: organic. Use utm_medium to capture the nature of the traffic, not the deep linking platform.
• utm_campaign: A lowercase-hyphenated campaign name that mirrors your Branch ~campaign parameter value where possible. For seasonal campaigns: summer-launch-jun-2026, black-friday-2026. For re-engagement campaigns: reengagement-lapsed-30d, cart-abandon-email. For referral programs: referral-program-2026. For Branch Journeys campaigns: journeys-install-banner, journeys-reopen-prompt. Aligning utm_campaign with your Branch campaign name makes it easier to cross-reference GA4 web session data with Branch attribution data in reporting.
• utm_content: Creative or variant identifier for A/B testing and creative performance analysis. For email campaigns with multiple CTA variants: utm_content=cta-hero, utm_content=cta-footer. For social campaigns with multiple ad formats: utm_content=video-15s, utm_content=carousel. Use utm_content to identify which version of a link drove the most web sessions — especially useful for Journeys A/B tests where different banner designs route to the same destination.
• utm_term: Keyword or audience segment. For paid search campaigns with Branch links: the search keyword. For audience-segmented retargeting campaigns: the audience segment identifier. Omit for brand and social campaigns where keyword-level tracking is not relevant.

See the UTM naming conventions guide for the full cross-platform taxonomy reference, and the UTM tracking for developers guide for programmatic generation and validation at scale.

FAQ

Does Branch automatically forward UTM parameters to the web fallback URL?

Branch can forward UTM parameters if you add them directly to the Branch link as query parameters (e.g., adding utm_source=branch&utm_medium=paid-social to the Branch link URL itself). Branch will then include those parameters in the $fallback_url redirect. However, this requires careful URL construction to avoid conflicts between Branch's own parameters and the UTM parameters in the link. The more reliable pattern is to build a fully tracked destination URL with mlz build and set it explicitly as the $fallback_url value in the Branch link configuration — this keeps UTM parameter management explicit, auditable, and consistent across all campaigns.

Why do my Branch campaign clicks show as Direct in GA4?

If Branch is attributing installs and deep link opens correctly but GA4 shows the resulting web sessions (from users who land on the $fallback_url) as Direct, UTM parameters are missing from the fallback destination URL. Build a tracked destination URL with mlz build --source "branch" --medium "[channel]" --campaign "your-campaign" --validate and update the $fallback_url in your Branch link to that tracked URL. Then run mlz check on the full Branch link URL to confirm UTM parameters survive the Branch redirect chain to the final destination.

Can I use Branch deep links and UTM parameters on the same campaign?

Yes. Branch deep link attribution (tracked via Branch's SDK using ~channel, ~campaign, ~feature) and GA4 web session attribution (tracked via UTM parameters on the $fallback_url) are completely independent measurement systems. Branch measures app opens and conversions via the SDK; GA4 measures web page sessions via URL query strings. Both can be active simultaneously with no conflict. Use both: Branch for app attribution, UTM parameters for web session attribution in GA4.

What is the difference between $fallback_url and $desktop_url in Branch?

$fallback_url is the catch-all web destination for any device or scenario where Branch cannot route to the app store or open the app. $desktop_url is a more specific override for desktop users only. If you set both, desktop users get $desktop_url and other web-fallback scenarios (tablet, unsupported browsers) get $fallback_url. If you only set $fallback_url, it covers all fallback scenarios including desktop. For most campaigns, setting a UTM-tagged URL as $fallback_url covers the majority of web attribution scenarios. If you use $desktop_url, generate separate tracked URLs for each with mlz build and validate each independently.

How do I handle Branch links in email campaigns where the email client strips query parameters?

Email clients that display HTML emails generally do not strip URL query parameters — query parameters are preserved when the user clicks a link in the email. The issue in email is more commonly that the ESP's own link tracking (click wrapping) adds a redirect that may or may not preserve UTM parameters. For Branch links used in email campaigns, test the complete email link (including ESP click tracking wrapping) with mlz check to verify UTM parameters survive the full redirect chain from email click → ESP redirect → Branch link → web fallback. See the redirect UTM stripping guide for diagnosis steps if parameters are dropped at any hop.

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