Resend's free tier caps daily sends tighter than monthly ones

The workload

Resend's pricing page separates a transactional email workload into four plans: Free, Pro, Scale and Enterprise. Verified: the Free plan states a limit of 3,000 emails a month with a 100-email daily cap and 3 verified sending domains, aimed at development and low-volume use. Moving past it requires verifying a sending domain's DNS records first, then choosing Pro or Scale once daily volume needs to exceed 100 messages, since the Free plan's daily cap, not just its monthly one, is what forces an upgrade for anything resembling a live product with real signups.

What the documents show

Verified: at their listed starting points, Pro costs $20 a month for 50,000 emails with 10 domains and no daily cap, and Scale costs $90 a month for 100,000 emails with up to 1,000 domains; both list an overage rate of $0.90 per additional 1,000 emails once the included allowance is used. The page presents these as starting figures on a volume selector that raises both the included allowance and the price together as a higher monthly volume is chosen; this entry states only the documented starting tier, since the selector's intermediate steps are rendered client-side and were not independently confirmed from static text. Verified: the Enterprise tier is the only one naming a reliability figure, a 99.99% uptime SLA, which the lower tiers do not carry. The docs introduction describes the product simply as 'the email API for developers,' consistent with the pricing page's framing.

The operating cost

A solo product sending fewer than 3,000 transactional emails a month (password resets, receipts, notifications) pays nothing under the Free plan, provided no single day exceeds 100 messages. Past that, the stated monthly cost is $20 for up to 50,000 emails or $90 for up to 100,000, each with a $0.90-per-1,000 overage beyond the included volume, both figures as published on 16 September 2026.

The stop condition

The page does not name a stop condition; it names thresholds where cost steps up. Editorially, the daily 100-email cap on the Free plan is the more consequential limit than the monthly count for many early products, because a single high-traffic day (a launch, a bulk password-reset event) can silently start failing sends rather than simply queuing them, which the page does not spell out as a behavior — only the numeric limit. A founder relying on the Free tier for anything customer-facing should treat the daily cap, not the monthly one, as the trigger to upgrade.

• Does any single day of sending realistically approach the 100-email Free-tier cap, even if the monthly total looks small?
• Is domain count (3, 10 or 1,000) a real constraint, or a number that will never bind for a one-product operation?
• At what monthly email volume does $0.90 per 1,000 in overage exceed the cost of simply moving to the next plan?

Read against its own numbers, the page prices a daily ceiling as much as a monthly one, and the daily figure is the one most likely to surprise a solo operator who only checked the monthly total before launch.