ConvertKit's field cap is 100—here's how to segment smarter
The coffee’s gone cold in your mug, your laptop fan is whirring, and you’re staring at a ConvertKit error message that says you’ve hit the custom field limit. It’s 11 p.m., the sequence was supposed to launch tomorrow, and you’ve just discovered that 100 fields is a ceiling, not a suggestion.
ConvertKit caps custom fields at 100—and most operators don’t know until they hit it
When segmentation complexity outgrows platform limits, you’re forced to redesign your data model or migrate.
ConvertKit doesn’t advertise the 100 custom field cap in pricing pages or feature comparisons. You find it when you try to create field 101 and the platform returns an error. At that point, your sequences, forms, and automation rules are already built around a taxonomy that no longer fits. If you’ve been tracking purchase history, content preferences, funnel stage, lead source, and behavioural flags as separate fields, you’ll hit the ceiling faster than you expect—especially if you’re running a multi-product business or segmenting by cohort.
The immediate workaround is field consolidation: combine related data into comma-separated values or JSON strings, then filter with “contains” logic instead of exact matches. That works for low-complexity segments, but it breaks down when you need to layer conditions or exclude subsets. The better long-term fix is to map your segmentation strategy before you build it—decide which attributes deserve dedicated fields, which can be inferred from tags, and which belong in a separate CRM or database that syncs summary flags back to ConvertKit. The 100-field limit isn’t negotiable, so your data model has to be.
TACTIC
Automation filters in ConvertKit apply in reverse order—and that changes everything
If your ConvertKit sequences aren’t firing when they should, the filter stack might be the problem. ConvertKit evaluates automation rule conditions bottom-to-top, which means the last filter you added is the first one checked. When you layer multiple conditions—segment membership, tag presence, custom field values—the order determines whether a subscriber qualifies. Most operators assume top-to-bottom logic and spend hours troubleshooting the wrong rule. Reordering filters fixes it in seconds once you know the pattern.
READER QUESTION
Referral programs count gross signups—but net growth is what actually matters
Referral widgets celebrate every new signup, but they don’t tell you how many unsubscribe a week after claiming the incentive. If you’re rewarding referrers based on raw acquisition numbers, you’re paying for churn. The better metric is net growth: signups minus unsubscribes within the first 30 days. That gives you a realistic picture of whether your referral programme is building an engaged audience or attracting freebie hunters who vanish the moment the reward arrives. Track both numbers before you scale the budget.
FROM THE ARCHIVE
Affiliate cookie windows expire long before your evergreen content stops driving clicks
Most affiliate programmes default to 30-day cookie windows, but your best-performing content keeps sending traffic for months or years. If a reader clicks your affiliate link in January, bookmarks your post, and buys in March, you don’t get credit. That mismatch punishes operators who invest in evergreen SEO and rewards those who chase launch cycles with tight conversion windows. The fix isn’t better content—it’s aligning your affiliate strategy with platforms that offer longer cookies or recurring commissions, so the value of a click compounds over time instead of expiring.
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