Developer-first email API (transactional and marketing) on a freemium model from $0 to custom enterprise, with 200,000+ developers signed up within 18 months of public launch as of December 2024.

Founder-led and open-source-anchored, running pure product-led growth with zero dedicated sales headcount.

~5.2M estimated monthly visits (+34.5% over the last 3 months as of the latest snapshot); 16,000 paying customers as of October 2025 growing at ~2,000 per month; $18M Series A from Andreessen Horowitz (a16z) closed December 2024.

Founder Zeno Rocha, on reaching 16,000 paying customers in October 2025: "No sales team yet. Just PLG" (product-led growth).

Zeno Rocha's decade of open-source contributions and 110+ developer conference talks generated a 20,000-person waitlist before Resend's public launch, making paid acquisition irrelevant at exactly the moment the PLG flywheel was gaining speed.