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/email-best-practices

@376d1c3 official
by resendresend/resend-skills193 stars
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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.

Ask your Agent

Use this Skill: https://skilld.dev/gh/resend/resend-skills/email-best-practices

This session only. Nothing lands on disk.

referencesdeliverability.md

≈855 tokens on demand. Your agent reads this file only when SKILL.md points to it.

Email Deliverability

Maximizing the chances that your emails are delivered successfully to the recipients.

Email Authentication

Required by Gmail/Yahoo/Microsoft - unauthenticated emails will be rejected or spam-filtered.

SPF (Sender Policy Framework)

Specifies which servers can send email for your domain.

v=spf1 include:amazonses.com ~all
  • Add TXT record to DNS
  • Use ~all (soft fail)

DKIM (DomainKeys Identified Mail)

Cryptographic signature proving email authenticity.

  • Your email service will provide you with a TXT record

DMARC

Policy for handling SPF/DKIM failures + reporting.

v=DMARC1; p=none; rua=mailto:dmarc@example.com

Rollout: p=none (monitor) → p=quarantine; pct=25 → p=reject

Learn more: https://resend.com/blog/dmarc-policy-modes

Verify Your Setup

Check DNS records directly:

# SPF record
dig TXT example.com +short

# DKIM record (replace 'resend' with your selector)
dig TXT resend._domainkey.example.com +short

# DMARC record
dig TXT _dmarc.example.com +short

Expected output: Each command should return your configured record. No output = record missing.

Sender Reputation

IP Warming

New IP/domain? Gradually increase volume:

Week Daily Volume
1 50-100
2 200-500
3 1,000-2,000
4 5,000-10,000

Start with engaged users. Send consistently. Don't rush.

Learn more: https://resend.com/docs/knowledge-base/warming-up

Maintaining Reputation

Do: Send to engaged users, keep bounce <4%, complaints <0.1%, remove inactive subscribers.

Don't: Send to purchased lists, ignore bounces/complaints, send inconsistent volumes

Bounce Handling

Type Cause Action
Hard bounce Permanent failure to deliver Remove immediately
Soft bounce Transient failure to deliver Retry: 1h → 4h → 24h, remove after 3-5 failures

Targets: <1% good, 1-3% acceptable, 3-4% concerning, >4% critical

Complaint Handling

Targets: <0.01% excellent, 0.01-0.05% good, >0.05% critical

Reduce complaints:

  • Only send to opted-in users
  • Make unsubscribe easy and immediate
  • Use clear sender names and "From" addresses

Feedback loops: Set up with Gmail (Postmaster Tools), Yahoo, Microsoft SNDS. Remove complainers immediately.

Infrastructure

Dedicated sending domain: Use different subdomains for different sending purposes (e.g., t.example.com for transactional emails and m.example.com for marketing emails).

DNS TTL: Low (300s) during setup, high (3600s+) after stable.

Troubleshooting

Emails going to spam? Check in order:

  1. Authentication (SPF, DKIM, DMARC)
  2. List-Unsubscribe header — required by Gmail/Yahoo since Feb 2024 (see Compliance)
  3. Sender reputation (blacklists, complaint rates)
  4. Content
  5. Sending patterns (sudden volume spikes)

Diagnostic tools:

Related

Source: SKILL.md on GitHub

Third-party checks

No alerts16d4 checks · Risk SAFE
  • Gen Agent Trust Hub16d

    The skill is a comprehensive knowledge base for email best practices, including deliverability, accessibility, compliance, and reliability. It contains educational content and code examples for developers. No malicious patterns or security risks were detected.

  • Socket16d

    No alerts

  • Snyk16d

    Risk: LOW · No issues

  • ZeroLeaks5mo

    Score: 93/100 · 2 sections analyzed

Provenance

Signed by skilld at 376d1c3. This ties the file your Agent reads to that commit on GitHub. It does not review the instructions.

Last checked against GitHub 2 days ago.

Activeupdated 4 months ago

Capability

Other metadata
metadata
{
  "author": "Resend",
  "version": "1.0.2",
  "homepage": "https://resend.com/agent-skills",
  "source": "https://github.com/resend/email-best-practices",
  "openclaw": {
    "links": {
      "repository": "https://github.com/resend/email-best-practices",
      "documentation": "https://resend.com/docs/email-best-practices-skill"
    }
  }
}

Topics

  • email
  • transactional
  • marketing
  • deliverability
  • spf-dkim-dmarc
  • compliance
  • webhooks
  • accessibility
  • list-management
  • resend

README badge

README badge for resend/resend-skills/email-best-practices

What it does

Provides decision trees and reference guides for deliverability (SPF/DKIM/DMARC), compliance (CAN-SPAM/GDPR/CASL), transactional vs marketing email classification, webhook handling, list management, and accessibility (alt text, headings, contrast). Targets teams building email features with Resend or similar transactional email APIs.

Generated from the current SKILL.md.

Frequently asked

Does this skill cover setting up SPF, DKIM, and DMARC?
Yes. The Deliverability section covers authentication setup and is the first step recommended for fixing spam issues, as unauthenticated emails are commonly rejected by Gmail and Yahoo.
What compliance standards does this skill address?
It covers CAN-SPAM, GDPR, and CASL requirements, with a dedicated Compliance section for legal obligations around email capture and marketing sends.
Does this skill include guidance on making emails accessible?
Yes. The Accessibility section covers screen reader support, alt text, headings, contrast requirements, and proper HTML structure for inclusive email design.
How does this skill handle bounces and list hygiene?
The List Management section covers bounce handling, suppression list updates, and list hygiene jobs. Webhooks & Events section covers processing delivery events to track bounces and complaints.
Does this skill cover retry logic and idempotent sending?
Yes. The Sending Reliability section covers retry strategy, idempotency, and error handling for production-ready email sending.

Generated from the current SKILL.md. These answers refresh after source changes.