The small "Best Seller" tag that occasionally shows up on Etsy listings looks like a marketing label, but it's actually generated automatically based on a listing's sales performance relative to other listings in the same category — not something a seller applies for or pays to unlock.
Etsy hasn't published the exact precise formula, but it's understood to be based on comparative sales velocity within a specific, fairly narrow category — meaning a listing can genuinely be a "best seller" within a smaller or less competitive category with a fairly modest sales volume, while a listing with significantly more raw sales in a huge, crowded category might not get the badge at all, simply because it's being compared against much stiffer category-wide competition.
This means category selection at the listing level actually matters for this specific badge, beyond just search relevance. Choosing the most accurate, specific category available (rather than a broader, more generic one) can affect not just whether shoppers filtering by category find you, but also the comparative pool your sales get measured against for badge purposes.
Is it worth actively chasing? The badge itself provides a small visual trust signal to shoppers browsing search results, similar in spirit to the Star Seller badge but based on a completely different metric (sales performance vs. seller behavior). It's a nice-to-have rather than something to restructure your whole strategy around — a listing that's already selling well tends to earn it as a natural byproduct, rather than needing a dedicated separate strategy.
Where it's actually useful practically: if you notice one of your listings has picked up the badge, that's a legitimate signal worth paying attention to — it means that specific listing is meaningfully outperforming its category, which makes it a good candidate to study for what's working (title, photos, pricing) and potentially replicate in adjacent designs, rather than just celebrating the badge itself and moving on.