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Custom attribution

  • Also called Meta custom attribution
  • Updated November 4, 2026

Custom attribution is one of Meta's three attribution models. You send Meta the credit your own analytics tool gives each Meta ad for a purchase, and delivery optimizes toward those numbers instead of Meta's default attribution. It works through the Conversions API or a supported analytics partner. Meta warns at the top of its page that it may not be available to you yet.

How does custom attribution work?

Meta's About custom attribution page calls it a model "that optimizes for outcomes as measured in your external analytics tool." The data arrives one conversion at a time:

For each conversion, you provide how much credit each Meta ad touchpoint deserves based on your attribution model. Instead of following Meta's default attribution model, the ad delivery system directly uses your attribution data to optimize toward the outcomes you measure.

Four partners are named: Adobe, Northbeam, Rockerbox and Triple Whale. Anyone else has to send the data through the Conversions API.

Can you turn it on for a running campaign?

No. "You can enable custom attribution on a new campaign only. It cannot be added to existing campaigns." There is a wait before that, too: "It typically takes 1-2 weeks of receiving high-quality signals before you will be able to create campaigns with custom attribution." The person who created the source gets an email when it is ready, and Events Manager shows data quality in the meantime.

The first line of the page still applies: "This product or feature may not be available to you yet." Meta doesn't say who has it, or when others will.

Who is it for?

Meta says it is best suited if you:

  • "Use your own attribution system or a supported analytics partner to make budget decisions across publishers."
  • "Can share order-level, click-through attribution credit and value back to Meta."
  • Run sales objective campaigns "optimizing for purchase events."
  • "Have a Conversions API connection or supported partner integration."
  • "Currently use/or willing to use highest value or highest volume" bidding.

It may not suit you if you "Focus on brand awareness or upper-funnel objectives rather than sales campaigns", or "Are satisfied with Meta's default attribution and see no significant gap with your own measurement."

The bidding line leaves out cost per result goals, ROAS goals and bid caps. See highest volume and highest value for what those two strategies give up.

How is it different from standard and incremental attribution?

Each model counts something else. Meta's Peak Season 2026 guide says standard is "what the ads touched", incremental is "what the ads added", and custom is "the way your business already counts it." Meta's attribution models page covers how you choose. The windows you pick under attribution setting belong to the standard model, and incremental attribution has its own page.

A lift test answers a different question. Custom attribution changes what delivery chases. It doesn't prove your analytics tool's credit is right, so if that tool over-credits one channel, Meta will now optimize toward the same error.

Will Ads Manager match your analytics tool?

Close, but Meta doesn't promise it. "While results and reporting in Ads Manager will reflect your data, there may be some differences between Meta's in-platform reporting and the data from your external analytics tool." Its advice is to keep using that tool "to compare and evaluate campaign performance."

What it means for your ads

Start with the gap. If your analytics tool and Ads Manager already tell the same story, Meta's list says this isn't for you. The case for it is a business that moves budget on its own numbers and keeps seeing Meta report something else.

Plan it as a new campaign with a warm-up, since the data has to flow for one to two weeks first. Comparing it against your existing campaign means comparing two ways of counting, so settle on which number decides before you start. Meta's Peak Season guide puts the risk this way: "If the one you optimise against isn't the one your finance team uses, you're reading a different campaign from the one you're running."

Sources

The page carries Meta's availability warning, so check your own account before planning around this.

Terrads makes ads that differ in concept and layout, so the credit your analytics tool assigns can point to a specific idea.