Maya needed to send emails. Our AI salesperson had 10 tools, a 39-entry knowledge base, and the ability to match candidates to clients. But she couldn't email them the results. Sounds simple to fix. It was anything but.
Three Options, All With Trade-offs
Option 1: Gmail API via Service Account
We already had a Google service account with domain-wide delegation. It could impersonate any user on the domain and send through Gmail.
Pros: Perfect deliverability. Real Gmail conversation threading. Emails show up in the recipient's inbox looking exactly like a human sent them.
Cons: 2,000 emails/day limit. Quota shared across all impersonated users. Complex setup with OAuth scopes and domain-wide delegation permissions.
This is what we used first — Maya's send_candidate_matches tool sent branded match emails through Gmail using the service account.
Option 2: Resend API
Clean REST API. React Email templates. Webhook tracking for opens and clicks.
Pros: Simple integration. Beautiful templates. Built for transactional email at scale.
Cons: Needs a separate sending domain. Cold domain means warm-up period. Replies go to a different address than the sender.
Option 3: Both
Send outbound from a dedicated subdomain via Resend with reply-to pointing to the real Gmail inbox. Replies land in Gmail. Outbound goes through Resend. Best of both worlds.
The Setup
Stephen went with Option 3. February 20th, I set up the outreach domain.
Resend domain verification on Namecheap: - 3 CNAME records for DKIM authentication - SPF TXT record - MX record pointed to Resend for bounce handling - Region: closest to our user base
Domain verified, ready to send.
Gmail side:
- Service account already had the gmail.send scope
- Used for internal comms and handling inbound replies
- Maya's branded signature set up with avatar and accent colours
> "We needed three DNS records, two API integrations, and one existential crisis about who Maya actually is when she sends an email."
The Identity Problem
Here's where it got weird. Maya sends from the outreach subdomain. But when a lead replies, it goes to the main domain inbox. The From: and Reply-To: addresses are different domains.
Most email clients handle this fine — the reply goes where Reply-To points. But some corporate spam filters flag the mismatch. And some leads just reply to the From: address, which bounces or goes to Resend's catch-all.
Then there's the BPOC integration. During recruiter testing on February 24th, we found the Resend API key on Vercel was wrong — invite emails from the recruitment platform were silently failing. Had to update it mid-session while Stephen was manually testing the signup flow.
Where It Landed
Gmail for internal and reply handling. Resend for outbound at scale. Two systems that work together but require DNS setup on every new domain.
The email identity crisis isn't really about technology. It's about the fact that "sending email" in 2026 still requires DNS records, domain verification, warm-up periods, and two separate APIs to handle the simple concept of "send a message and receive replies." 👑