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GroundmailGroundmail/groundmail-skills/skills/email-best-practices/SKILL.md

email-best-practices

Skill0 starsChanged 23 days agoMITView on GitHub

Use when writing or reviewing transactional email for deliverability and safety — SPF/DKIM/DMARC, verified domains, suppressions, bounce handling, API key hygiene, sandbox vs production, unsubscribe for bulk-like mail. Pair with groundmail when integrating Groundmail.

  • Reads credentials

12 other projects use a version of this.

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Used with

Projects with it also use react-email, resend-cli and 7 more.

Other files people use alongside this one.

Files found in the same public projects as a version of this one, more often than they turn up anywhere else. Each project counts once, large collections count for less, and this file's own repository is left out.
  • VercelSkill

    react-email

    React Email renderer for json-render that turns JSON specs into HTML or plain-text emails using @react-email/components and @react-email/render. Use when working with @json-render/react-email, building transactional or marketing emails from JSON, creating email catalogs, rendering AI-generated email specs, or when the user mentions react-email, HTML email, or transactional email.

    Also in 7 projects that use this

  • resendSkill

    resend-cli

    Operate the Resend platform from the terminal — send emails (including React Email .tsx templates via --react-email), manage domains, contacts, broadcasts, templates, webhooks, API keys, logs, automations, and events via the `resend` CLI. Use when the user wants to run Resend commands in the shell, scripts, or CI/CD pipelines, or send/preview React Email templates. Always load this skill before running `resend` commands — it contains the non-interactive flag contract and gotchas that prevent silent failures.

    Also in 4 projects that use this

  • MoizIbnYousafSkill

    agent-email-inbox

    Use when setting up a secure email inbox for any AI agent — configuring inbound email via Resend, webhooks, tunneling for local development, and implementing security measures to prevent prompt injection attacks. Also use when someone mentions 'agent email', 'bot inbox', 'receive emails for agent', 'agent webhook', 'email security for AI', 'prompt injection via email', 'inbound email for bot', or wants their AI agent to receive and respond to emails securely.

    Also in 3 projects that use this

  • VercelSkill

    resend

    Emulated Resend email API for local development and testing. Use when the user needs to send emails locally, test transactional email flows, implement magic link or verification code auth, inspect sent emails, manage domains/contacts/API keys, or work with the Resend API without sending real emails. Triggers include "Resend API", "emulate Resend", "send email locally", "test email", "magic link", "verification email", "email inbox", "RESEND_BASE_URL", or any task requiring a local email API.

    Also in 4 projects that use this

  • VercelSkill

    next-cache-components-optimizer

    Optimize the meaningful UI available immediately from a Next.js route on an initial load (hard navigation) or named client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route and entry point at a time; the shipped test then guards against regression. Use when asked to grow a static shell, fix a slow first paint or non-instant navigation, diagnose which Suspense boundary blocks useful UI, or add instant() regression coverage. Requires Next.js 16.3+ with Cache Components already adopted.

    Also in 3 projects that use this

  • SentrySkill

    vercel-composition-patterns

    Also in 3 projects that use this

  • +1 more from vercel-labs

The file

Show its rules and text

We split this skill into the rules it gives an agent

15 rules. 0 are common, 11 are distinctive, and 4 are very specific to this project.

  • 0

    Common

    Most of the 12 edited versions we read keep these.

  • 11

    Distinctive

    This author's own choices. Worth a look.

  • 4

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Very specific:

    Never ship gm_ keys to browsers, mobile apps, or public repos

    line 25
  2. Distinctive:

    Ensure SPF, DKIM (and ideally DMARC) are correct for that domain — Groundmail domain verify checks the records it publishes

    line 33
  3. Distinctive:

    Do not send high volume from a brand-new domain without gradual ramp-up

    line 34
  4. Very specific:

    Prefer a dedicated subdomain for mail (e.g.

    line 35
  5. Distinctive:

    Never use the sandbox sender for customer-facing production mail.

    line 47
  6. Distinctive:

    After hard bounces / complaints, check suppressions before retrying

    line 53
  7. Distinctive:

    Do not hammer the same address after bounce

    line 54
  8. Very specific:

    Use GET /suppressions (or CLI/MCP) before bulk retries

    line 55
  9. Distinctive:

    Treat spam complaints as permanent opt-outs for that address

    line 56
  10. Distinctive:

    If mail is subscription-like, include unsubscribe and honor it

    line 64
  11. Distinctive:

    Avoid misleading subjects.

    line 65
  12. Distinctive:

    Prefer plain text + HTML multipart when possible.

    line 66
  13. Distinctive:

    Prefer sandbox self-test or sends to your own verified addresses

    line 72
  14. Very specific:

    Do not test with invented @gmail.com / @outlook.com addresses — they bounce and hurt reputation

    line 73
  15. Distinctive:

    Do not claim guaranteed inbox placement or full mailbox-provider telemetry

    line 81

“Common” is measured: kept by at least 6 in 10 of the 12 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

Email best practices (transactional)

Guidance for agents shipping password resets, receipts, invites, and other transactional mail on Groundmail.

Auth and secrets

  • Store API keys in server env only (GROUNDMAIL_API_KEY)
  • Never ship gm_ keys to browsers, mobile apps, or public repos
  • Rotate keys if exposed; delete unused dashboard keys

Domains and DNS

  • Production from must use a verified domain in the sending account
  • Ensure SPF, DKIM (and ideally DMARC) are correct for that domain — Groundmail domain verify checks the records it publishes
  • Do not send high volume from a brand-new domain without gradual ramp-up
  • Prefer a dedicated subdomain for mail (e.g. mail.example.com or notifications.example.com) when the root domain already sends elsewhere

Sandbox vs production

Modefromto
Sandbox self-testnoreply@mail.groundmail.devAccount email only
Verified domain (billing not set up)Address on verified customer domainAccount email only
Free production / paidAddress on verified customer domainReal recipients

Never use the sandbox sender for customer-facing production mail. Unlock Free production with a verified domain and billing set up in the dashboard.

Suppressions and bounces

  • After hard bounces / complaints, check suppressions before retrying
  • Do not hammer the same address after bounce
  • Use GET /suppressions (or CLI/MCP) before bulk retries
  • Treat spam complaints as permanent opt-outs for that address

Content and compliance

  • Transactional only in this product path — no purchased lists or cold outbound here
  • Include clear sender identity and a way to get help
  • If mail is subscription-like, include unsubscribe and honor it
  • Avoid misleading subjects; match body to subject
  • Prefer plain text + HTML multipart when possible; keep HTML simple for clients

Testing

  • Prefer sandbox self-test or sends to your own verified addresses
  • Do not test with invented @gmail.com / @outlook.com addresses — they bounce and hurt reputation
  • Confirm webhook handlers verify signatures before acting on events

Metrics honesty

  • Dashboard / GET /deliverability numbers are best-effort from stored events
  • Do not claim guaranteed inbox placement or full mailbox-provider telemetry

React Email

Author and preview with React Email’s tools; send via Groundmail SDK (react option or pre-rendered HTML). Keep keys server-side.

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