> ## Documentation Index > Fetch the complete documentation index at: https://resend.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Introduction > A collection of answers to frequently asked questions. ## Domains & Verification > **[How do I avoid conflicts with my MX records?](/docs/knowledge-base/how-do-i-avoid-conflicting-with-my-mx-records)** > > Add DNS records without conflicting with existing MX records. > **[What if my domain is not verifying?](/docs/knowledge-base/what-if-my-domain-is-not-verifying)** > > What to do when your domain isn't verifying. ## DNS Guides Step-by-step instructions for verifying your domain with popular DNS providers. > **[Cloudflare DNS Guide](/docs/guides/dns/cloudflare)** > **[Gandi DNS Guide](/docs/guides/dns/gandi)** > **[GoDaddy DNS Guide](/docs/guides/dns/godaddy)** > **[DreamHost DNS Guide](/docs/guides/dns/dreamhost)** > **[Hetzner DNS Guide](/docs/guides/dns/hetzner)** > **[Hostinger DNS Guide](/docs/guides/dns/hostinger)** > **[IONOS DNS Guide](/docs/guides/dns/ionos)** > **[Namecheap DNS Guide](/docs/guides/dns/namecheap)** > **[Porkbun DNS Guide](/docs/guides/dns/porkbun)** > **[Route 53 DNS Guide](/docs/guides/dns/route53)** > **[Squarespace DNS Guide](/docs/guides/dns/squarespace)** > **[Strato DNS Guide](/docs/guides/dns/strato)** > **[Vercel DNS Guide](/docs/guides/dns/vercel)** ## Deliverability > **[How do I avoid Gmail's spam folder?](https://resend.com/guides/email/deliverability/avoid-gmail-spam-folder)** > > Learn how to improve inbox placement in Gmail. > **[Why Are My Emails Going to Spam?](/docs/knowledge-base/why-are-my-emails-going-to-spam)** > > Troubleshoot emails landing in spam or getting quarantined. > **[Is it better to send from a subdomain or root domain?](/docs/knowledge-base/is-it-better-to-send-emails-from-a-subdomain-or-the-root-domain)** > > Discover why sending emails from a subdomain can be better than using a root > domain. > **[Why are my emails landing on the suppression list?](/docs/knowledge-base/why-are-my-emails-landing-on-the-suppression-list)** > > Learn why your emails land on the suppression list, and how to remove them. > **[Domain and IP Warm-up Guide](/docs/knowledge-base/warming-up)** > > Learn how to warm up your domain and dedicated IP for optimal deliverability. ## Sending > **[Account Quotas and Limits](/docs/knowledge-base/account-quotas-and-limits)** > > Understand the sending quotas and rate limits for your Resend account. > **[How do Dedicated IPs Work?](/docs/knowledge-base/how-do-dedicated-ips-work)** > > Learn how Dedicated IPs work and how to request them. > **[What sending feature should I use?](/docs/knowledge-base/what-sending-feature-to-use)** > > Find the right Resend feature for your email sending use case. > **[Should I add an unsubscribe link?](/docs/knowledge-base/should-i-add-an-unsubscribe-link)** > > Learn when to add unsubscribe links to your transactional and marketing > emails. ## Tutorials > **[Maximize deliverability for Supabase Auth emails](/docs/knowledge-base/how-do-i-maximize-deliverability-for-supabase-auth-emails)** > > Everything you should do before sending authentication emails with Resend and > Supabase. > **[How do I set up Apple Branded Mail?](/docs/knowledge-base/how-do-i-set-up-apple-branded-mail)** > > Display your brand logo in the Apple Mail inbox. > **[How do I send with an avatar?](/docs/knowledge-base/how-do-i-send-with-an-avatar)** > > Learn how to show your avatar in the inbox of your recipients. > **[Forward emails with Resend Inbound](/docs/knowledge-base/forward-emails-with-resend-inbound)** > > Set up email forwarding using Resend's inbound email processing. > **[Template emails with React Email](/docs/knowledge-base/template-emails-with-react-email)** > > Author email templates as React components and upload them to Resend with the > CLI. > **[Embed the React Email editor](/docs/knowledge-base/embed-react-email-editor)** > > Add the open-source visual email editor to your own application. ## Troubleshooting > **[How do I fix CORS issues?](/docs/knowledge-base/how-do-i-fix-cors-issues)** > > Recommended options to avoid CORS errors when sending emails. > **[403 Error: Domain Mismatch](/docs/knowledge-base/403-error-domain-mismatch)** > > Resolve 403 errors when the sending domain doesn't match your verified domain. > **[Domain Already Registered by Another Account](/docs/knowledge-base/domain-already-registered)** > > Resolve domain ownership conflicts when a domain is already registered. > **[Email says delivered but not received?](/docs/knowledge-base/what-if-an-email-says-delivered-but-the-recipient-has-not-received-it)** > > Steps to take when an email is delivered but the recipient hasn't received it. ## AI Tools > **[AI Onboarding](/docs/ai-onboarding)** > > Everything you need to onboard your AI agent to Resend. > **[MCP Server](/docs/mcp-server)** > > Use Resend's Model Context Protocol server to send emails from AI tools. > **[Email Best Practices Skills](/docs/email-best-practices-skill)** > > Skills for AI agents to build production-ready email systems with Resend. > **[React Email Skill](/docs/react-email-skill)** > > Skills for AI agents to build HTML emails using React components with Resend. > **[Resend Skill](/docs/resend-skill)** > > Skills for AI agents to send emails with Resend. ## Account Management > **[What is Resend Pricing?](/docs/knowledge-base/what-is-resend-pricing)** > > Learn more about Resend's pricing plans. > **[How can I delete my Resend account?](/docs/knowledge-base/how-can-i-delete-my-resend-account)** > > Learn how to permanently delete your Resend account and data. > **[How to handle API keys](/docs/knowledge-base/how-to-handle-api-keys)** > > Best practices for managing and securing your Resend API keys. > **[How to handle a leaked API key](/docs/knowledge-base/how-to-handle-a-leaked-api-key)** > > What to do when an API key is exposed or used without authorization. > **[How to add multi-factor authentication to your Resend account](/docs/knowledge-base/how-can-i-add-mfa)** > > Enable or disable multi-factor authentication (MFA) or two-factor > authentication (2FA) on your Resend account. ## Testing > **[E2E Testing with Playwright](/docs/knowledge-base/end-to-end-testing-with-playwright)** > > Set up end-to-end email testing with Playwright and Resend. > **[What email addresses to use for testing?](/docs/knowledge-base/what-email-addresses-to-use-for-testing)** > > Use Resend's test email addresses to simulate different delivery scenarios.