Give OpenClaw an email address with Resend

Your Operator.io agent already runs around the clock. Once you connect Resend, it can also send email from your own domain, so the morning brief, the follow up you keep forgetting, or the weekly update to a client goes out as a real email instead of sitting in a chat window. Resend is a developer focused transactional email API: you verify a domain, create an API key, and call a REST endpoint to send. OpenClaw handles the composition and the send call through its built in Resend skill. This guide walks through the whole setup, from the Resend side to the moment you ask OpenClaw to send something.

What you get

The Resend skill lets OpenClaw compose and send email through your Resend account, and list what it has already sent so you have a record to check. It writes the body as HTML, so a brief arrives with real headings, links, and structure rather than a wall of plain text, and it pulls from its memory and files so the content is yours. The agent sends from an address on a domain you control, so the mail looks like it came from you. The from address takes the usual shape of a name and an address, like Sara <sara@yourdomain.com>, and the agent fills that in for you. In practice that covers things like:

• A morning brief or a weekly client update sent on a schedule.
• The follow up email you keep meaning to write.
• A one off note you dictate in a sentence and have it expand and send.

Resend delivers mail over SMTP, the standard protocol mail servers use to hand messages off to each other. Your agent never talks to SMTP directly; it calls Resend's send email API, and Resend handles authentication, routing, and bounce processing. The HTML body follows MIME conventions, the same structure Gmail and Outlook expect, which is why a formatted brief renders correctly in a normal inbox instead of showing raw tags.

Before you start

You need a Resend account and a domain whose DNS you can edit. Resend requires that you own the domain, so shared or public domains will not pass verification. The free tier is plenty for trying this out and for light ongoing use, and the Pro plan lifts the caps once you send in volume:

Resend counts each recipient in the To, CC, or BCC fields as a separate email toward both limits, so a message with three people on CC uses four of your daily allowance. If you do not have a domain yet, you can buy one from any registrar and point it at Resend in a few minutes.

Step 1: Verify your domain in Resend

Resend will only send from a domain you have proven you own. The verification step adds two DNS records that tell the rest of the internet Resend is allowed to send on your behalf.

Resend's own walkthrough adds a domain and pastes the SPF and DKIM records into a DNS provider, the same steps the agent depends on before it can send a single message.

1. In the Resend dashboard, open Domains and add your domain. A subdomain like mail.yourdomain.com is a good choice. Resend recommends a subdomain over the root domain because inbound MX records on the root can conflict with outbound sending setup.
2. Resend gives you SPF and DKIM records to add at your DNS provider. SPF (Sender Policy Framework) is a TXT record listing the servers authorized to send mail for your domain. DKIM (DomainKeys Identified Mail) is a TXT record with a public key receivers use to verify the message was not altered in transit. Copy the values Resend shows, or use the auto configure option if your registrar supports it.
3. Back in Resend, click Verify DNS Records. Verification usually finishes within a few minutes, though DNS propagation can take up to 72 hours depending on your provider.

Full instructions, including registrar specific guides, live in the Resend domains documentation. If your domain happens to be on Cloudflare, Resend can configure the records automatically through Domain Connect, or OpenClaw can add those SPF and DKIM records for you once you have connected Cloudflare. After SPF and DKIM verify, Resend lets you add an optional DMARC record that tells receivers what to do with mail failing authentication checks. DMARC is not required to send, but it helps with deliverability on Gmail, Outlook, and other major providers.

Step 2: Create an API key

Open API Keys in the Resend dashboard and click Create API Key. Give it a name you will recognize later and choose Sending access if you want to limit the key to sending mail only. Resend shows the key only once, so copy it before you close the dialog. It starts with re_. You can restrict a key to a specific verified domain if you run more than one. The full reference is in the Resend API keys docs.

Step 3: Add the key to Operator

In your Operator dashboard, open Environment and click Add. Name the variable RESEND_API_KEY and paste the key as the value. The value is encrypted and shown to you only once, the same way Resend handles it. OpenClaw looks the key up by name when it sends mail, so you never paste it into a chat and it never shows up in OpenClaw's config.

The Resend skill is already installed on OpenClaw, so there is nothing else to deploy. As soon as the key is saved, the agent can use it.

Step 4: Make sure you can reach OpenClaw

You talk to your Operator agent from Telegram or Discord. If you have not connected one yet, open the channels page and set up whichever you prefer. That is where the agent confirms what it sent and asks you anything it needs along the way.

Step 5: Ask it to send something

Now message OpenClaw the way you would message anyone else. A couple of things to try:

Email jane@acme.com a short note thanking her for the call today and suggesting we meet again next week.

Every Friday at 4pm, email me a summary of what you got done this week, pulled from your work log.

The first is a one off, and the second is the one that pays off over time: a standing instruction the agent turns into a scheduled job, so the email arrives every week without you thinking about it. Those two examples sit at different stakes, and it helps to treat them that way.

A summary that lands in your own inbox is yours to ignore if it gets something wrong. A note to jane@acme.com leaves from your verified domain, so to her it reads as mail from you, and a scheduled send that fires while you are asleep does that with no draft in front of you. The arrangement that stays comfortable is letting the agent mail you on a schedule freely and asking it to show the draft before anything goes to someone else, particularly on a recurring job you set once and stop watching.

Since the agent writes from its memory and files, glance at what it pulled in as well, so a figure or a private note you kept for yourself does not ride along in a message to a client. You can also ask it to CC or BCC people, attach a file from its workspace, or reply in thread if Resend has the original message ID on record.

Good to know

Email from a brand new domain can land in spam until the domain builds some reputation, so start with low volume and real messages rather than a blast. Gmail and Outlook both weigh SPF, DKIM, and DMARC alignment when deciding whether to accept or filter mail from a sender they have not seen before. The free tier's daily cap of 100 emails is the limit most people meet first, and hitting it returns an error until the day resets. Resend's account quotas page spells out how sent and received mail both count toward the monthly total. If you plan to send in any volume, the Pro plan at $20 a month removes the daily cap and raises the monthly allowance to 50,000 emails.

When a send fails, the usual cause is a domain that has not finished verifying or a key whose sending access was restricted to a different domain, and both take a few seconds to check in the Resend dashboard. Resend also publishes delivery events (sent, delivered, bounced, complained) that you can wire to a webhook if you want the agent to react when a message bounces. For HTML heavy templates, Resend maintains React Email, a component library for building email layouts in code; the agent's skill handles simpler HTML directly, but the same Resend account supports both paths if you want richer templates later.