A self-hosted AgentMail alternative on your own Cloudflare
AgentMail is a hosted inbox API priced by inboxes and email volume. MarkRelay gives agents mailboxes on your own domain, inside your own Cloudflare account, for one license.
Facts checked
The short answer
Choose AgentMail if you want a hosted inbox API with SDKs, SMTP relay and a SOC 2 report, and you are happy for mail to live on AgentMail's servers. Choose MarkRelay when agents should use mailboxes on your own domain inside your own Cloudflare account, with no per-inbox or per-domain fee: each agent gets a mailbox and a key scoped to it, a signed webhook on new mail, and the same mailboxes stay usable by people in webmail.
Side by side
| Feature | MarkRelayLicense from $99/yr | AgentMailHosted, free tier, then from $20/mo |
|---|---|---|
| Where mail is stored | Your Cloudflare D1 + R2 | AgentMail's cloud |
| Inboxes | No app limit or per-inbox fee | 3 free, 10 on Developer, then $2/mo each |
| Custom domains | Any domain on Cloudflare DNS | From the Developer plan |
| HTTP API: send, read, reply, forward | Yes | Yes |
| Signed webhooks for new mail | Yes | Yes |
| Keys limited to chosen mailboxes | Yes | Not stated |
| Webmail for people on the same mailboxes | Yes | Not stated |
| Agent skill for Claude Code, Codex, OpenClaw, Hermes | Yes | Not stated |
| llms.txt, MCP server, SDKs | llms.txt, OpenAPI and MCP server | Yes |
| SMTP relay | No | Yes |
| Broadcasts and templates | Yes | No |
| Compliance report | No | SOC 2 (Startup plan) |
Where mail is stored
- MarkRelay
- Your Cloudflare D1 + R2
- AgentMail
- AgentMail's cloud
Inboxes
- MarkRelay
- No app limit or per-inbox fee
- AgentMail
- 3 free, 10 on Developer, then $2/mo each
Custom domains
- MarkRelay
- Any domain on Cloudflare DNS
- AgentMail
- From the Developer plan
HTTP API: send, read, reply, forward
- MarkRelay
- Yes
- AgentMail
- Yes
Signed webhooks for new mail
- MarkRelay
- Yes
- AgentMail
- Yes
Keys limited to chosen mailboxes
- MarkRelay
- Yes
- AgentMail
- Not stated
Webmail for people on the same mailboxes
- MarkRelay
- Yes
- AgentMail
- Not stated
Agent skill for Claude Code, Codex, OpenClaw, Hermes
- MarkRelay
- Yes
- AgentMail
- Not stated
llms.txt, MCP server, SDKs
- MarkRelay
- llms.txt, OpenAPI and MCP server
- AgentMail
- Yes
SMTP relay
- MarkRelay
- No
- AgentMail
- Yes
Broadcasts and templates
- MarkRelay
- Yes
- AgentMail
- No
Compliance report
- MarkRelay
- No
- AgentMail
- SOC 2 (Startup plan)
AgentMail facts are from agentmail.to/pricing. “Not stated” means its pricing page does not say.
Which one fits you
Choose AgentMail if
- You want a fully hosted service and SDKs out of the box.
- You need SMTP relay or a SOC 2 report.
- You are not on Cloudflare and do not plan to be.
Choose MarkRelay if
- Agents should send from your own domain, and mail should stay in your account.
- You run many agent mailboxes, or several domains, and do not want to pay per inbox or per domain.
- People and agents share mailboxes: humans review in webmail, agents work over the API.
- You also want team webmail, broadcasts and templates in the same app.
What agent mailboxes cost
| Example | AgentMailFrom $20/mo, priced by inboxes and emails | MarkRelayLicense $8.25/mo ($99/yr) + Cloudflare | You savePer month |
|---|---|---|---|
| 10 agent mailboxes, 10,000 emails a month | $20Developer plan | $15.70$8.25 license + $5 Workers Paid + $2.45 sending | $4.3021% less |
| 25 agent mailboxes, 20,000 emails a month | $70Developer plan + add-ons | $19.20$8.25 license + $5 Workers Paid + $5.95 sending | $50.8072% less |
| 25 agent mailboxes on 15 domains, 20,000 emails a month | $80Developer plan + add-ons | $19.20$8.25 license + $5 Workers Paid + $5.95 sending | $60.8076% less |
| 100 agent mailboxes, 50,000 emails a month | $200Startup plan | $29.70$8.25 license + $5 Workers Paid + $16.45 sending | $170.3085% less |
10 agent mailboxes, 10,000 emails a month
AgentMail
MarkRelay
25 agent mailboxes, 20,000 emails a month
AgentMail
MarkRelay
25 agent mailboxes on 15 domains, 20,000 emails a month
AgentMail
MarkRelay
100 agent mailboxes, 50,000 emails a month
AgentMail
MarkRelay
MarkRelay: the Annual license ($99/year) spread over 12 months, $8.25 a month whatever the volume, plus the Cloudflare bill: Workers Paid is $5/month with 3,000 sent emails included, then $0.35 per 1,000, and receiving is free. With Lifetime ($249 once), later years cost only the Cloudflare bill. Mailboxes and domains cost nothing. AgentMail: the cheaper of the Developer plan ($20/mo with 10 inboxes, 10,000 emails and 10 custom domains, plus $2 per extra inbox, per extra 1,000 emails and per extra domain) and the Startup plan ($200/mo, 150 inboxes, 150 domains).
An agent's mailbox loop
Everything goes over plain HTTP with a key scoped to the agent's own mailbox.
- MarkRelayPOST
your-agent/webhookSigned email.received event the moment mail arrives
- AgentGET
/emails/{emailId}Reads the full message and attachments
- You, optionally
Approve the draftKeep a human in the loop for sensitive replies
- AgentPOST
/emails/{emailId}/replyReplies in the same thread, from agent@yourdomain.com
# The agent's key was created for agent@acme.com only$curl -H "Authorization: Bearer $MARKRELAY_API_KEY" "$MARKRELAY_API_URL/mailboxes"{"items":[{"id":"mb_agent","address":"agent@acme.com","displayName":"Acme Triage Agent"}]}# Another team's mailbox is invisible to it$curl -H "Authorization: Bearer $MARKRELAY_API_KEY" "$MARKRELAY_API_URL/emails?mailbox=support@acme.com"{"code":"not_found","message":"Mailbox not found"}# Its own mail: read, then reply in the same thread$curl -H "Authorization: Bearer $MARKRELAY_API_KEY" "$MARKRELAY_API_URL/emails?mailbox=agent@acme.com&folder=inbox"{"items":[{"id":"b68419a2-…","subject":"Reset my password please","from":{"name":"Sam Patel",…}}, …]}$curl -X POST -H "Authorization: Bearer $MARKRELAY_API_KEY" -H "Content-Type: application/json" \ "$MARKRELAY_API_URL/emails/b68419a2-…/reply" -d '{"text":"Hi Sam, I have sent a fresh reset link…"}'{"id":"528a8469-74ee-4dc4-8023-0d3882699ad2"}
Common questions
Can an AI agent use MarkRelay without a hosted service?
Yes. MarkRelay runs as a Worker in your own Cloudflare account. The agent calls your deployment's API directly with its own key; no third-party inbox service is involved.
Does it work with Claude Code, Codex, OpenClaw and Hermes?
Yes. Create a mailbox for the agent and a key scoped to it, then install the skill your deployment serves at /skills/SKILL.md: into ~/.claude/skills for Claude Code, ~/.agents/skills for Codex, OpenClaw and Pi, or with hermes skills install for Hermes. Set MARKRELAY_API_URL and MARKRELAY_API_KEY. Other agents can read the deployment's llms.txt or OpenAPI spec.
Can people and agents share a mailbox?
Yes. A teammate can review and answer in webmail while the agent works over the API on the same mailbox, so handing a thread from agent to human needs no export.
What does MarkRelay cost for many agents?
One license (Annual $99/year or Lifetime $249 once) covers any number of mailboxes and domains. Cloudflare bills sending: Workers Paid includes 3,000 emails a month, then $0.35 per 1,000. For 25 agent mailboxes on 15 domains sending 20,000 emails a month, that is about $19.20 a month with the license spread over the year, against $80 on AgentMail.
Keep reading
Own your email stack today
Buy MarkRelay once and run it in your Cloudflare account. MarkRelay adds no per-message or per-seat charge; Cloudflare usage and service limits remain separate.