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Email Best Practices

ResendOfficialCreated by Resend

  • Skill
  • Guidelines
  • Business and productivity
  • MIT
  • No issues found
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From the author

Use when building email features, emails going to spam, high bounce rates, setting up SPF/DKIM/DMARC authentication, implementing email capture, ensuring compliance (CAN-SPAM, GDPR, CASL), handling webhooks, retry logic, making emails accessible (alt text, headings, contrast, screen readers), or deciding transactional vs marketing.
— the description by Resend

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured framework for managing the entire lifecycle of email communications. It covers technical infrastructure like SPF/DKIM/DMARC authentication, legal compliance across major jurisdictions (GDPR, CAN-SPAM, CASL), and accessibility standards for screen readers and diverse email clients. It also offers guidance on transactional versus marketing email strategies, list management, and building reliable delivery pipelines with retry logic and webhooks.

What it does

  • Provides technical guidance for email authentication (SPF, DKIM, DMARC) to improve deliverability.
  • Outlines legal requirements for global email compliance including GDPR, CAN-SPAM, and CASL.
  • Defines accessibility standards for email content, including screen reader support and contrast.
  • Offers architectural patterns for transactional and marketing email workflows.
  • Details best practices for list management, bounce handling, and suppression lists.
  • Explains how to implement reliable sending with idempotency, retries, and webhook event tracking.

When to use it

  • When setting up a new email infrastructure for an application.
  • When troubleshooting high bounce rates or emails landing in spam folders.
  • When designing transactional email templates like password resets or order confirmations.
  • When implementing email capture forms that require legal consent tracking.
  • When auditing existing email templates for accessibility and compliance.

Advantages

  • Reduces the risk of legal penalties by providing clear compliance guidelines.
  • Improves email deliverability by standardizing authentication and list hygiene.
  • Ensures emails are accessible to all users, including those using assistive technology.
  • Provides a clear architectural path for building production-ready email systems.
  • Helps distinguish between transactional and marketing email strategies to optimize engagement.

Usage examples

“What are the legal requirements for sending marketing emails to users in the EU versus the US?”
The agent provides a comparison of GDPR and CAN-SPAM, highlighting the need for explicit opt-in consent for GDPR and the requirement for physical addresses and opt-out mechanisms for CAN-SPAM.
“How do I make my transactional email templates accessible for screen readers?”
The agent outlines specific HTML requirements, such as setting lang/dir attributes, using role='presentation' for layout tables, and ensuring proper heading hierarchy.
“My emails are going to spam. What should I check first?”
The agent directs the user to the deliverability reference to verify DNS authentication (SPF, DKIM, DMARC) and check for common configuration issues.

Install

  1. Download the skill as a ZIP:

    https://mp-staging.autogineer.com/agent-skills/resend/email-best-practices/download

  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip email-best-practices.zip -d .agents/skills

Documentation by Resend

Email Best Practices

Guidance for building deliverable, compliant, user-friendly emails.

Architecture Overview

[User] → [Email Form] → [Validation] → [Double Opt-In]
                                              ↓
                                    [Consent Recorded]
                                              ↓
[Suppression Check] ←──────────────[Ready to Send]
        ↓
[Idempotent Send + Retry] ──────→ [Email API]
                                       ↓
                              [Webhook Events]
                                       ↓
              ┌────────┬────────┬─────────────┐
              ↓        ↓        ↓             ↓
         Delivered  Bounced  Complained  Opened/Clicked
                       ↓        ↓
              [Suppression List Updated]
                       ↓
              [List Hygiene Jobs]

Quick Reference

Need to...See
Set up SPF/DKIM/DMARC, fix spam issuesDeliverability
Build password reset, OTP, confirmationsTransactional Emails
Plan which emails your app needsTransactional Email Catalog
Build newsletter signup, validate emailsEmail Capture
Send newsletters, promotionsMarketing Emails
Ensure CAN-SPAM/GDPR/CASL complianceCompliance
Decide transactional vs marketingEmail Types
Handle retries, idempotency, errorsSending Reliability
Process delivery events, set up webhooksWebhooks & Events
Manage bounces, complaints, suppressionList Management
Make emails accessible (screen readers, alt text, contrast)Accessibility

Start Here

New app? Start with the Catalog to plan which emails your app needs (password reset, verification, etc.), then set up Deliverability (DNS authentication) before sending your first email.

Spam issues? Check Deliverability first—authentication problems are the most common cause. Gmail/Yahoo reject unauthenticated emails.

Marketing emails? Follow this path: Email Capture (collect consent) → Compliance (legal requirements) → Marketing Emails (best practices).

Production-ready sending? Add reliability: Sending Reliability (retry + idempotency) → Webhooks & Events (track delivery) → List Management (handle bounces).

Accessibility? Most emails fail basic accessibility checks. See Accessibility for lang/dir, presentational tables, headings, alt text, <title>, and contrast.

Files

references/transactional-email-catalog.md

Transactional Email Catalog

A comprehensive catalog of transactional emails organized by category, plus recommended email combinations for different app types.

When to Use This

  • Planning what transactional emails your app needs

  • Choosing the right emails for your app type

  • Understanding what content each email type should include

  • Implementing transactional email features

Email Combinations by App Type

Use these combinations as a starting point based on what you're building.

Authentication-Focused App

Apps where user accounts and security are core (login systems, identity providers, account management).

Essential:

  • Email verification

  • Password reset

  • OTP / 2FA codes

  • Security alerts (new device, password change)

  • Account update notifications

Optional:

  • Welcome email (must not be promotional)

  • Account deletion confirmation

Newsletter / Content Platform

Apps focused on content delivery and subscriptions.

Essential:

  • Email verification

  • Password reset

  • Welcome email (must not be promotional)

  • Subscription confirmation

Optional:

  • OTP / 2FA codes

  • Account update notifications

E-commerce / Marketplace

Apps where users buy products or services.

Essential:

  • Email verification

  • Password reset

  • Welcome email (must not be promotional)

  • Order confirmation

  • Shipping notifications

  • Invoice / receipt

  • Payment failed notices

Optional:

  • OTP / 2FA codes

  • Security alerts

  • Subscription confirmations (for recurring orders)

SaaS / Subscription Service

Apps with paid subscription tiers and ongoing billing.

Essential:

  • Email verification

  • Password reset

  • Welcome email (must not be promotional)

  • OTP / 2FA codes

  • Security alerts

  • Subscription confirmation

  • Subscription renewal notice

  • Payment failed notices

  • Invoice / receipt

Optional:

  • Account update notifications

  • Feature change notifications (for breaking changes)

Financial / Fintech App

Apps handling money, payments, or sensitive financial data.

Essential:

  • Email verification

  • Password reset

  • OTP / 2FA codes (required for sensitive actions)

  • Security alerts (all types)

  • Account update notifications

  • Transaction confirmations

  • Invoice / receipt

  • Payment failed notices

Optional:

  • Welcome email (must not be promotional)

  • Compliance notices

Social / Community Platform

Apps focused on user interaction and community features.

Essential:

  • Email verification

  • Password reset

  • Welcome email (must not be promotional)

  • Security alerts

Optional:

  • OTP / 2FA codes

  • Account update notifications

  • Activity notifications (mentions, replies)

Developer Tools / API Platform

Apps targeting developers with API access and integrations.

Essential:

  • Email verification

  • Password reset

  • OTP / 2FA codes

  • Security alerts

  • API key notifications (creation, expiration)

  • Subscription confirmation

  • Payment failed notices

Optional:

  • Welcome email (must not be promotional)

  • Usage alerts (approaching limits)

  • Feature change notifications

Healthcare / HIPAA-Compliant App

Apps handling protected health information.

Essential:

  • Email verification

  • Password reset

  • OTP / 2FA codes (required)

  • Security alerts (all types, detailed)

  • Account update notifications

  • Appointment confirmations

Optional:

  • Welcome email (must not be promotional)

  • Compliance notices

Note: Healthcare apps have strict requirements. Emails should contain minimal PHI and link to secure portals for sensitive information.

Full Email Catalog

Authentication & Security
Email Verification / Account Verification

When to send: Immediately after user signs up or changes email address.

Purpose: Verify the email address belongs to the user.

Content should include:

  • Clear verification link or code

  • Expiration time (typically 24-48 hours)

  • Instructions on what to do

  • Security notice if link is clicked by mistake

Best practices:

  • Send immediately (within seconds)

  • Include expiration notice

  • Provide resend option

  • Link to support if issues

OTP / 2FA Codes

When to send: When user requests two-factor authentication code.

Purpose: Provide time-sensitive authentication code.

Content should include:

  • The OTP code (clearly displayed)

  • Expiration time (typically 5-10 minutes)

  • Security warnings

  • Instructions on what to do if not requested

Best practices:

  • Send immediately

  • Code should be large and easy to read

  • Include expiration prominently

  • Warn about sharing codes

  • Provide "I didn't request this" link

Password Reset

When to send: When user requests password reset.

Purpose: Allow user to securely reset forgotten password.

Content should include:

  • Reset link (with token)

  • Expiration time (typically 1 hour)

  • Security warnings

  • Instructions if not requested

Best practices:

  • Send immediately

  • Link expires quickly (1 hour)

  • Include IP address and location if available

  • Provide "I didn't request this" link

  • Don't include the old password

Security Alerts

When to send: When security-relevant events occur (login from new device, password change, etc.).

Purpose: Notify user of account security events.

Content should include:

  • What happened (clear description)

  • When it happened

  • Location/IP if available

  • Action to take if suspicious

  • Link to security settings

Best practices:

  • Send immediately

  • Be clear and specific

  • Include actionable steps

  • Provide way to report suspicious activity

Account Management
Welcome Email

When to send: Immediately after successful account creation and verification.

Purpose: Welcome new users and guide them to next steps (must not be promotional).

Content should include:

  • Welcome message

  • Key features or next steps

  • Links to important resources

  • Support contact information

Best practices:

  • Send after email verification

  • Keep it focused and actionable

  • Don't overwhelm with information

  • Set expectations about future emails

Account Update Notifications

When to send: When user changes account settings (email, password, profile, etc.).

Purpose: Confirm account changes and provide security notice.

Content should include:

  • What changed

  • When it changed

  • Action to take if unauthorized

  • Link to account settings

Best practices:

  • Send immediately after change

  • Be specific about what changed

  • Include security notice

  • Provide easy way to revert if needed

E-commerce & Transactions
Order Confirmations

When to send: Immediately after order is placed.

Purpose: Confirm order details and provide receipt.

Content should include:

  • Order number

  • Items ordered with quantities

  • Pricing breakdown

  • Shipping address

  • Estimated delivery date

  • Order tracking link (if available)

Best practices:

  • Send within minutes of order

  • Include all order details

  • Make it easy to print or save

  • Provide customer service contact

Shipping Notifications

When to send: When order ships, with tracking updates.

Purpose: Notify user that order has shipped and provide tracking.

Content should include:

  • Order number

  • Tracking number

  • Carrier information

  • Expected delivery date

  • Tracking link

  • Shipping address confirmation

Best practices:

  • Send when order ships

  • Include tracking number prominently

  • Provide carrier tracking link

  • Update on major tracking milestones

Invoices and Receipts

When to send: After payment is processed.

Purpose: Provide payment confirmation and receipt.

Content should include:

  • Invoice/receipt number

  • Payment amount

  • Payment method

  • Items/services purchased

  • Payment date

  • Downloadable PDF (if applicable)

Best practices:

  • Send immediately after payment

  • Include all payment details

  • Make it easy to download/save

  • Include tax information if applicable

Subscriptions & Billing
Subscription Confirmations

When to send: When user subscribes or changes subscription.

Purpose: Confirm subscription details and billing information.

Content should include:

  • Subscription plan details

  • Billing amount and frequency

  • Next billing date

  • Payment method

  • Link to manage subscription

Best practices:

  • Send immediately after subscription

  • Clearly state billing terms

  • Provide easy cancellation option

  • Include support contact

Subscription Renewal Notices

When to send: Before subscription renews (typically 3-7 days before).

Purpose: Notify user of upcoming renewal and charge.

Content should include:

  • Renewal date

  • Amount to be charged

  • Payment method on file

  • Link to update payment method

  • Link to cancel if desired

Best practices:

  • Send with enough notice (3-7 days)

  • Be clear about amount and date

  • Make it easy to update payment method

  • Provide cancellation option

Payment Failed Notices

When to send: When subscription payment fails.

Purpose: Notify user of payment failure and provide resolution steps.

Content should include:

  • What happened

  • Amount that failed

  • Reason for failure (if available)

  • Steps to resolve

  • Link to update payment method

  • Consequences if not resolved

Best practices:

  • Send immediately after failure

  • Be clear about consequences

  • Provide easy resolution path

  • Include support contact

Notifications & Updates
Feature Announcements (Transactional)

When to send: When a feature the user is using changes significantly.

Purpose: Notify users of changes that affect their use of the service.

Content should include:

  • What changed

  • How it affects the user

  • What action (if any) is needed

  • Link to more information

Best practices:

  • Only for significant changes

  • Focus on user impact

  • Provide clear next steps

  • Link to documentation

Note: General feature announcements are marketing emails. Only send as transactional if the change directly affects an active feature the user is using.

Related Topics

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Created by
Resend
Publisher
Resend (Official)
Source
resend/resend-skills · skills/email-best-practices · commit 389de56
Licence
MIT License (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

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Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download email-best-practices.zip