email

Q: How do I install email?

Run npx skills add https://github.com/merit-systems/agentcash-skills --skill email in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/email/ (personal) or .claude/skills/email/ (project).

by merit-systemsProductivity & Automation

Send emails, buy forwarding inboxes, manage custom subdomains, and read messages programmatically via x402. USE FOR: - Sending emails (one-off or from custom addresses) - Buying a forwarding inbox (username@stableemail.dev) - Purchasing custom email subdomains (you@yourname.stableemail.dev) - Reading and managing inbox messages programmatically - Setting up catch-all forwarding for subdomains - Managing authorized signers for shared subdomains TRIGGERS: - "send email", "email this to", "notify by email" - "buy inbox", "forwarding address", "email inbox" - "custom domain", "subdomain", "email subdomain" - "read emails", "check inbox", "list messages" - "email address", "disposable email", "temporary email" ALWAYS use npx agentcash@latest fetch for stableemail.dev endpoints. IMPORTANT: Use exact endpoint paths from the Quick Reference table below.

Installs: 141
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Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/merit-systems/agentcash-skills --skill email

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads email automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Email with StableEmail

Send emails, manage inboxes, and run custom subdomains via x402 payments at https://stableemail.dev.

Setup

See rules/getting-started.md for installation and wallet setup.

Quick Reference

Task	Endpoint	Price
Send email (shared)	`https://stableemail.dev/api/send`	$0.02
Buy subdomain	`https://stableemail.dev/api/subdomain/buy`	$5.00
Send from subdomain	`https://stableemail.dev/api/subdomain/send`	$0.005
Buy inbox	`https://stableemail.dev/api/inbox/buy`	$1.00
Send from inbox	`https://stableemail.dev/api/inbox/send`	$0.005
Top up inbox (30d)	`https://stableemail.dev/api/inbox/topup`	$1.00
Top up inbox (90d)	`https://stableemail.dev/api/inbox/topup/quarter`	$2.50
Top up inbox (365d)	`https://stableemail.dev/api/inbox/topup/year`	$8.00
List inbox messages	`https://stableemail.dev/api/inbox/messages`	$0.001
Read inbox message	`https://stableemail.dev/api/inbox/messages/read`	$0.001
Create subdomain inbox	`https://stableemail.dev/api/subdomain/inbox/create`	$0.25
List subdomain messages	`https://stableemail.dev/api/subdomain/inbox/messages`	$0.001
Read subdomain message	`https://stableemail.dev/api/subdomain/inbox/messages/read`	$0.001

Free Management Endpoints

Task	Endpoint
Subdomain status	`GET https://stableemail.dev/api/subdomain/status?subdomain=name`
Update subdomain	`POST https://stableemail.dev/api/subdomain/update`
Manage signers	`POST https://stableemail.dev/api/subdomain/signers`
Inbox status	`GET https://stableemail.dev/api/inbox/status?username=name`
List your inboxes	`POST https://stableemail.dev/api/inbox/list`
Update inbox	`POST https://stableemail.dev/api/inbox/update`
Cancel inbox	`POST https://stableemail.dev/api/inbox/cancel`
Delete message	`POST https://stableemail.dev/api/inbox/messages/delete`
List subdomain inboxes	`POST https://stableemail.dev/api/subdomain/inbox/list`
Delete subdomain inbox	`POST https://stableemail.dev/api/subdomain/inbox/delete`
Update subdomain inbox	`POST https://stableemail.dev/api/subdomain/inbox/update`
Delete subdomain message	`POST https://stableemail.dev/api/subdomain/inbox/messages/delete`

Free endpoints use SIWX wallet authentication (handled automatically by npx agentcash@latest fetch).

Send an Email

Send from the shared relay@stableemail.dev address:

npx agentcash@latest fetch https://stableemail.dev/api/send -m POST -b '{
  "to": ["recipient@example.com"],
  "subject": "Hello from x402",
  "html": "<h1>Hi!</h1><p>This email was sent via x402 payments.</p>",
  "text": "Hi! This email was sent via x402 payments.",
  "replyTo": "your-real-email@example.com"
}'

Parameters:

to — array of recipient emails (required)
subject — email subject (required)
html and/or text — email body (at least one required)
replyTo — reply-to address (optional but recommended)
attachments — array of {content, contentType, filename} (optional, max 5, base64 encoded, ~3.75MB limit each)

Attachment example:

{
  "attachments": [{
    "content": "base64-encoded-content...",
    "contentType": "application/pdf",
    "filename": "report.pdf"
  }]
}

For calendar invites, use contentType: "text/calendar; method=REQUEST".

Forwarding Inbox

Buy username@stableemail.dev for $1/month. Emails are forwarded to your real address and/or retained for programmatic access.

Buy an Inbox

npx agentcash@latest fetch https://stableemail.dev/api/inbox/buy -m POST -b '{
  "username": "alice",
  "forwardTo": "alice@gmail.com"
}'

Omit forwardTo to use as a programmatic-only mailbox (retainMessages auto-enabled).

Send from Inbox

npx agentcash@latest fetch https://stableemail.dev/api/inbox/send -m POST -b '{
  "username": "alice",
  "to": ["bob@example.com"],
  "subject": "Hello",
  "html": "<p>Hi Bob</p>",
  "text": "Hi Bob"
}'

Top Up Inbox

npx agentcash@latest fetch https://stableemail.dev/api/inbox/topup -m POST -b '{"username": "alice"}'

Anyone can top up any inbox. Top-ups stack. Bulk discounts: 90 days/$2.50 (17% off), 365 days/$8 (34% off).

Cancel and Refund

npx agentcash@latest fetch https://stableemail.dev/api/inbox/cancel -m POST -b '{"username": "alice"}'

Returns pro-rata USDC refund on-chain automatically.

Read Inbox Messages

Enable message retention, then read messages programmatically.

Enable Retention

npx agentcash@latest fetch https://stableemail.dev/api/inbox/update -m POST -b '{"username": "alice", "retainMessages": true}'

List Messages

npx agentcash@latest fetch https://stableemail.dev/api/inbox/messages -m POST -b '{"username": "alice", "limit": 20}'

Read a Message

npx agentcash@latest fetch https://stableemail.dev/api/inbox/messages/read -m POST -b '{"messageId": "msg_abc123"}'

Returns full message with from, to, subject, date, text, html, and attachment download URLs (URLs expire after 1 hour). Message content and attachments are retained for 90 days.

Custom Subdomains

Buy yourname.stableemail.dev for $5 one-time. Send from any address on your subdomain for $0.005/email.

Buy a Subdomain

npx agentcash@latest fetch https://stableemail.dev/api/subdomain/buy -m POST -b '{"subdomain": "yourname"}'

Rules: 3-30 chars, lowercase alphanumeric + hyphens. DNS verification takes ~5 minutes.

Send from Subdomain

npx agentcash@latest fetch https://stableemail.dev/api/subdomain/send -m POST -b '{
  "from": "support@yourname.stableemail.dev",
  "to": ["customer@example.com"],
  "subject": "Your order confirmation",
  "html": "<p>Thank you for your order!</p>"
}'

Create Subdomain Inboxes

Create per-address inboxes on your subdomain ($0.25 each, max 100 inboxes, 500 messages each):

npx agentcash@latest fetch https://stableemail.dev/api/subdomain/inbox/create -m POST -b '{
  "subdomain": "yourname",
  "localPart": "support",
  "forwardTo": "team@company.com"
}'

Catch-All Forwarding

Forward all unmatched addresses on your subdomain:

npx agentcash@latest fetch https://stableemail.dev/api/subdomain/update -m POST -b '{"subdomain": "yourname", "catchAllForwardTo": "catch-all@company.com"}'

Manage Authorized Signers

Allow other wallets to send from your subdomain:

npx agentcash@latest fetch https://stableemail.dev/api/subdomain/signers -m POST -b '{"action": "add", "subdomain": "yourname", "walletAddress": "0x..."}'

Images in Emails

Host images on StableUpload or AgentUpload, then reference in HTML:

<img src="https://f.stableupload.dev/abc/photo.png" alt="Photo" />

Most email clients strip data URIs — always use hosted URLs.

Workflows

Quick Send

(Optional) Check balance: npx agentcash@latest balance
Send email via /api/send
Confirm delivery via messageId

Set Up Professional Email

Buy subdomain ($5)
Wait for DNS verification (~5 min)
Create inboxes for team members ($0.25 each)
Set up catch-all forwarding
Send from custom addresses ($0.005 each)

Programmatic Mailbox

Buy inbox with no forwardTo ($1)
Messages are retained automatically (90 days)
List and read messages via API ($0.001 each)
Delete messages when processed (free)

Cost Estimation

Task	Cost
Send one email (shared)	$0.02
Send one email (subdomain/inbox)	$0.005
Buy inbox (30 days)	$1.00
Buy inbox (1 year)	$1.00 + $8.00 = $9.00
Buy subdomain + 5 inboxes	$5.00 + $1.25 = $6.25
Read 100 messages	$0.10

FAQ

What does the email skill do?

How do I install email?

Run npx skills add https://github.com/merit-systems/agentcash-skills --skill email in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/email/ (personal) or .claude/skills/email/ (project).

Which AI agents can use email?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is email safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains email?

It is published by merit-systems in merit-systems/agentcash-skills. It has 141 recorded installs.