Resend Forge is a mail transfer agent Resend built for the transactional email its customers already send through the API. Until this launch, that mail left on infrastructure the company rented. Forge sends from IP blocks Resend owns and operates, with no other provider between the API call and the address a message leaves from. The company announced it at Resend Forward and opened activation on October 23, 2026. Existing customers add one CNAME record. Code, SMTP credentials, and webhooks stay the same, and sending continues while DNS and sender reputation are checked. Resend says Forge is 129 times faster at the 99th percentile than its previous engine, and reports a delivery rate above 99 percent across Gmail, Outlook, and Yahoo. In the comparison published with the announcement, median time to delivery across providers was 0.8 seconds on Forge and 1.6 seconds on the older path. Hundreds of customers had already sent more than 10 million messages through Forge before the public rollout. If Forge cannot finish a delivery, mail falls back to the previous engine on its own. That shows up for teams sending password resets, receipts, and product notifications, where tail latency and the reputation of the sending IPs decide whether mail lands. Founders Zeno Rocha, Bu Kinoshita, and Jonni Lundy started Resend in 2023, after the open source React Email project, and joined Y Combinator's Winter 2023 batch. Forge is the first version of that product running on mail servers and address space the company controls. Customers share those IP blocks with other Resend senders, which is why activation still depends on a correct domain setup and a sender-reputation check.