--- name: resend-inbound description: Use when receiving emails with Resend - setting up inbound domains, processing email.received webhooks, retrieving email content/attachments, or forwarding received emails. --- # Receive Emails with Resend ## Overview Resend processes incoming emails for your domain and sends webhook events to your endpoint. **Webhooks contain metadata only** - you must call separate APIs to retrieve email body and attachments. ## Quick Start 1. **Configure receiving domain** - Use Resend's `.resend.app` domain or add MX record for custom domain 2. **Set up webhook** - Subscribe to `email.received` event 3. **Retrieve content** - Call Receiving API for body, Attachments API for files ## Domain Setup ### Option 1: Resend-Managed Domain (Fastest) Use your auto-generated address: `@.resend.app` No DNS configuration needed. Find your address in Dashboard → Emails → Receiving → "Receiving address". ### Option 2: Custom Domain Add MX record to receive at `@yourdomain.com`. | Setting | Value | |---------|-------| | **Type** | MX | | **Host** | Your domain or subdomain | | **Value** | Provided in Resend dashboard | | **Priority** | 10 (**lowest number** wins a conflict, but typically only multiples of 10 are used) | **Critical:** Your MX record must have the lowest priority value, or emails won't route to Resend. ### Subdomain Recommendation If you already have MX records (e.g., Google Workspace, Microsoft 365): | Approach | Result | |----------|--------| | **Use subdomain** (recommended) | `support.acme.com` → Resend, `acme.com` → existing provider | | **Use root domain** | All email routes to Resend (breaks existing email) | ``` # Example: receive at support.acme.com without affecting acme.com support.acme.com. MX 10 ``` If you set up Resend to receive email on a root domain, *all* traffic will be routed to Resend, not to any other mailbox. It's crucial, then, to use a subdomain with inbound emails. ## Webhook Setup ### Subscribe to `email.received` Dashboard → Webhooks → Add Webhook → Select `email.received` For local development, use tunneling (ngrok, VS Code Port Forwarding): ```bash ngrok http 3000 # Use https://abc123.ngrok.io/api/webhook as endpoint ``` ### Webhook Payload Structure **Important:** Payload contains metadata only, not email body or attachment content. ```json { "type": "email.received", "created_at": "2024-02-22T23:41:12.126Z", "data": { "email_id": "a1b2c3d4-...", "from": "sender@example.com", "to": ["support@acme.com"], "cc": [], "bcc": [], "subject": "Question about my order", "attachments": [ { "id": "att_abc123", "filename": "receipt.pdf", "content_type": "application/pdf" } ] } } ``` ### Verify Webhook Signatures Always verify signatures to prevent spoofed events: ```typescript import { Resend } from 'resend'; const resend = new Resend(process.env.RESEND_API_KEY); export async function POST(req: Request) { const payload = await req.text(); const event = resend.webhooks.verify({ payload, headers: { 'svix-id': req.headers.get('svix-id'), 'svix-timestamp': req.headers.get('svix-timestamp'), 'svix-signature': req.headers.get('svix-signature'), }, secret: process.env.RESEND_WEBHOOK_SECRET, }); if (event.type === 'email.received') { // Process the email } return new Response('OK', { status: 200 }); } ``` ## Retrieving Email Content Webhooks exclude email body and headers. Call the Receiving API to get them: ```typescript if (event.type === 'email.received') { const { data: email } = await resend.emails.receiving.get( event.data.email_id ); console.log(email.html); // HTML body console.log(email.text); // Plain text body console.log(email.headers); // Email headers } ``` **Why this design?** Serverless environments have request body size limits. Separating content retrieval supports large emails and attachments. ## Handling Attachments ### Get Attachment Metadata and Download URLs ```typescript const { data: attachments } = await resend.emails.receiving.attachments.list({ emailId: event.data.email_id, }); for (const attachment of attachments) { console.log(attachment.filename); console.log(attachment.download_url); // Valid for 1 hour console.log(attachment.expires_at); } ``` ### Download Attachment Content ```typescript const response = await fetch(attachment.download_url); const buffer = await response.arrayBuffer(); // Save to storage, process, etc. await saveToStorage(attachment.filename, buffer); ``` **Important:** `download_url` expires after 1 hour. Call the API again for a fresh URL if needed. ## Forwarding Emails Complete workflow to receive and forward an email with attachments: ```typescript import { Resend } from 'resend'; const resend = new Resend(process.env.RESEND_API_KEY); export async function POST(req: Request) { const payload = await req.text(); const event = resend.webhooks.verify({ /* ... */ }); if (event.type === 'email.received') { // 1. Get email content const { data: email } = await resend.emails.receiving.get( event.data.email_id ); // 2. Get attachments (if any) const { data: attachmentList } = await resend.emails.receiving.attachments.list({ emailId: event.data.email_id, }); // 3. Download and encode attachments const attachments = await Promise.all( attachmentList.map(async (att) => { const res = await fetch(att.download_url); const buffer = Buffer.from(await res.arrayBuffer()); return { filename: att.filename, content: buffer.toString('base64'), }; }) ); // 4. Forward the email await resend.emails.send({ from: 'Support System ', to: ['team@acme.com'], subject: `Fwd: ${email.subject}`, html: email.html, text: email.text, attachments, }); } return new Response('OK', { status: 200 }); } ``` ## Routing by Recipient All emails to your domain arrive at the same webhook. Route based on the `to` field: ```typescript if (event.type === 'email.received') { const recipient = event.data.to[0]; if (recipient.includes('support@')) { await handleSupportEmail(event.data); } else if (recipient.includes('billing@')) { await handleBillingEmail(event.data); } else { await handleUnknownEmail(event.data); } } ``` ## Common Mistakes | Mistake | Fix | |---------|-----| | Expecting body in webhook payload | Webhook has metadata only - call `resend.emails.receiving.get()` for body | | MX record not lowest priority | Ensure Resend's MX has lowest number (highest priority) | | Adding MX to root domain with existing email | Use subdomain to avoid breaking existing email service | | Using expired download_url | URLs expire after 1 hour - call attachments API again for fresh URL | | Not verifying webhook signatures | Always verify - attackers can send fake events | | Forgetting to return 200 OK | Resend retries on non-200 responses | ## Storage Note Resend stores received emails even if: - Webhook isn't configured yet - Webhook endpoint is down View all received emails in Dashboard → Emails → Receiving tab. --- Source attribution: growupanand Original project: https://github.com/growupanand/ConvoForm/blob/71b43c34fd73e3bb58123d255ee18e123ebea4b1/.agents/skills/resend/resend-inbound/SKILL.md License: MIT License information: https://opensource.org/license/mit Original upstream instructions; downloaded from Dave AI. ## Upstream license notice MIT License Copyright (c) 2026 Resend Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Dave AI resource metadata Creator / publisher: growupanand Original project: https://github.com/growupanand/ConvoForm/blob/71b43c34fd73e3bb58123d255ee18e123ebea4b1/.agents/skills/resend/resend-inbound/SKILL.md Attribution basis: Source repository record Fields of work: Marketing, Sales Roles: Customer Success Manager, Email Marketer, Growth Marketer Specialties: API Tools: Resend Country applicability: Country not specified Classification basis: Source catalog labels Instruction SHA-256: 1418b5320d36ba37ac969e0679e80d252331b012fded4a166b38830697d083b8