The open-source email API for applications and AI agents

Send transactional email from any product, give agents real two-way inboxes, and keep people in control. Hosted plans start free, or run the Apache-2.0 stack yourself.

Free

$0 / month

For exploration and side projects.

  • 3 agents
  • 3 custom domains
  • 3,000 sends / month
  • 100 sends / day (lifted by any add-on)
  • 1 GiB storage
  • SPF / DKIM verification
  • Real-time WebSocket delivery
  • Includes "Created with e2a" footer
Start free

Starter

$10 / month

For individual builders connecting custom domains.

  • 10 agents
  • 5 custom domains
  • 20,000 sends / month
  • 5 GiB storage
  • SPF / DKIM verification
  • HITL approval workflow
  • Webhook + WebSocket delivery
  • Email support
Upgrade to Starter
Most popular

Pro

$20 / month

For production agents that send daily.

  • 25 agents
  • 10 custom domains
  • 50,000 sends / month
  • 10 GiB storage
  • HITL approval workflow
  • Webhook + WebSocket delivery
  • Email support
Upgrade to Pro

Scale

$99 / month

For agent fleets at production volume.

  • 250 agents
  • 150 custom domains
  • 200,000 sends / month
  • 100 GiB storage
  • Everything in Pro
  • Priority support
Upgrade to Scale

Every plan includes transactional sending, webhooks, WebSockets, structured SPF / DKIM / DMARC evidence, and optional human approval. Plans differ by quotas, branding, and support. Allowances count outbound sends only — one send per recipient, per account, resetting at the start of each calendar month (UTC); inbound mail is free and unmetered on every plan.

Add-on

$2 / month per inbox

Extra capacity on any tier — including Free.

  • +1 inbox per unit
  • +3,000 sends / month per unit, pooled into your account allowance
  • Removes the Free plan's 100 sends / day cap
  • Add units anytime (charged prorated); reduce anytime (no partial-month refund)
Add inboxes

Frequently asked questions

How much does e2a cost?

e2a has four self-serve tiers, plus a $2/month inbox add-on available on every tier. Free is $0/month and includes 3 agents, 3 custom domains, and 3,000 sends per month with no card required. Starter is $10/month for 10 agents, 5 custom domains, and 20,000 sends. Pro is $20/month for 25 agents, 10 custom domains, and 50,000 sends. Scale is $99/month for 250 agents, 150 custom domains, and 200,000 sends. Inbound mail is free and unmetered on every tier. Higher volumes are handled through enterprise pricing.

Is there a free tier for giving an AI agent an email address?

Yes. The Free tier costs nothing and requires no credit card. It covers 3 agents, 3 custom domains, 3,000 sends per month (up to 100 sends per day), and 1 GiB of storage, and includes SPF/DKIM verification on inbound mail and real-time WebSocket delivery. Received mail is free and unmetered, and buying any inbox add-on removes the daily cap.

Can I self-host e2a instead of paying for the hosted service?

Yes. e2a is open source under Apache-2.0 at github.com/tokencanopy/e2a and can be self-hosted against your own Postgres and outbound mail relay at no license cost. The paid tiers cover the hosted service at e2a.dev, which runs that same codebase.

What counts as a send?

Only outbound mail counts. Each recipient of a sent message counts as one send, so a message to 3 recipients uses 3 sends. Received mail is free and unmetered. The allowance is per account rather than per agent, and it resets at the start of each calendar month in UTC.

Can I add capacity without changing tiers?

Yes. The inbox add-on costs $2/month per inbox, and each one also adds 3,000 sends per month to your account's shared pool. It is available on every tier, including Free, and buying any add-on removes the Free plan's 100 sends per day cap (the "Created with e2a" footer stays with the Free plan). You can adjust the quantity at any time; added units are charged prorated for the rest of the month, and reductions apply immediately with no partial-month refund.