10-way split subject line testing

Has anyone setup a 10 way subject line split within a canvas and also set up an "auto-select" where each subsequent challenger is selected automatically using winning path? There's limitations where we can only use up to 4 splits for experiments paths and if I were to use audience path, there's a limitation up to 8. I can build on top of one another but I want to ensure the winning path is auto selected and sent. Is there an easy way to handle this request in Braze?

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jerome_ahkan

Hey @c_hixon - we’ve explored something similar using Intelligent Selection within canvas and it can help with the auto-picking a winner over time requirement since it optimises toward a conversion event.

That said, there are a couple of constraints to be aware of:
- Intelligent Selection supports up to 8 variants in a canvas, so it won’t fully cover a 10-way subject line test in one go
- The standard Experiment Path and Audience Path limits of 4 and 8 variants respectively, still apply, so you can’t natively run a clean 10-way split with auto-winner selection in a single canvas.

One approach that may work for you is to potentially group subject lines into themes (e.g. urgency, curiosity, offer-driven) then use Intelligent Selection across those themes, and let it optimise toward the best-performing group. From there, you can run a follow-up experiment (or a new canvas) to refine within the winning theme.

It’s not a perfect single-pass solution, but it balances scale with automation and still gets you to a strong winning subject line over time

elyssa

Hi @c_hixon, as Jerome mentioned, I wonder if it's worth defining 'waves' of testing, as depending on your audience size and the winning metric, you might not see results for a very long time, with 10 different variants (if it were possible)?

TedScott

While you could split the audience first to connect multiple experiments, you would not be able to get it so automatically select a single winner out of the 10.

It would be helpful to better understand your end goal, what you are testing, the nature of the canvas, how big the audience is / who many will flow through the canvas each month.

EmPaulin

While technically possible to approximate this setup, strategically I wouldn’t recommend it.

A 10-way split introduces more complexity than signal. You’re diluting learning velocity in exchange for theoretical precision that you likely won’t reach—especially if volume or conversion events are constrained.

From a systems perspective, this creates three issues:

More variants = longer time to confidence. You’re optimizing slower, not smarter.
Managing multiple paths, follow-ups, and interpretation becomes heavier than the insight gained.
The “best” of 10 in a low-signal environment is often just noise winning.

A more effective approach is staged learning:

Group subject lines into distinct behavioral angles (urgency, curiosity, value, etc.)
Let the system converge on which psychological lever works, not just which wording wins.
Run a second pass to optimize language once the strategy is validated.

This trades breadth for signal clarity and gets you to a durable insight faster.