Migration from Resend to ZeptoMail
Zoho ZeptoMail is a dedicated transactional email service built for reliable, high-speed delivery of critical emails such as password resets, order confirmations, OTPs, and system alerts.
This guide explains how to migrate your transactional email setup from Resend to Zoho ZeptoMail including account creation, data migration, domain verification, and email-sending configuration.
Note
ZeptoMail is a dedicated transactional email service. Ensure that it is used only for transactional emails and not for marketing or bulk email campaigns. If you are looking for a bulk email provider, you can visit Zoho Campaigns.
Terminology mapping
The table below maps commonly used Resend terms to their ZeptoMail equivalents:
| SendGrid | ZeptoMail |
| Domains | Domains |
| Templates | Templates |
| Email logs | Processed emails |
| Webhooks | Webhooks |
Before Migration
Before you begin migrating from Resend to ZeptoMail, ensure you have the following in place:
- Your Resend account API key.
- Any critical transactional email logs exported for reference.
- All templates, webhooks, and domain data are reviewed and up to date.
Migrating from Resend to ZeptoMail
There are two ways to migrate from Resend to ZeptoMail, depending on whether you are new to ZeptoMail or already have an existing account. Once you start migration, the following data will be migrated from your Resend account:
- Domains
- Email templates
- Webhooks
Migration for new ZeptoMail users
For the new users, migration can be initiated during account setup.
ZeptoMail Account Creation
- Navigate to the ZeptoMail homepage and click Get started from the top right corner.
- Enter the relevant details and click Sign up for free.
- Verify your account using the verification code sent to your registered mobile number.
- If you are already using other Zoho services and have an existing Zoho account, click Access ZeptoMail and proceed with the next steps.
- Once you sign up and verify yourself, you will be directed to the Welcome page.
- Enter your organization name.
- Review the terms and conditions and click Get started.
- Add the domain you will use for sending transactional emails and click Add.
- Once the domain is added successfully, you will be redirected to the ZeptoMail dashboard.
A short survey will appear asking how you found ZeptoMail. Select Resend from the drop-down list and click Save. This will take you to the migration setup screen.
Migration process
Once you see the migration setup screen:
- Click Let's begin.
- Enter the Account API key copied from your Resend account and click Validate.
- Once validated, click Migrate to start the migration process.
You can view the progress of your data migration in the migration window. Upon successful migration, the Resend account data will be migrated into a single Agent in ZeptoMail, along with the associated templates and webhooks.
An Agent in ZeptoMail is similar to a Project in Resend. Agents help segment different types of transactional emails based on their purpose, application, or workflow. Segmenting emails using Agents enables better organization and management. You can associate one or more verified domains with each Agent to send emails.
Migration for existing ZeptoMail users
To migrate a Resend account into an existing ZeptoMail account:
- In your ZeptoMail account, go to Settings.
- Select Migration and click New Migration from the top right corner.
- Choose Resend and click Start Now.
- Enter the Account API key copied from your Resend account and click Validate.
Once validated, click Migrate to start the migration process.
You can view the progress of your data migration in the migration window. Upon successful migration, the Resend account data will be migrated into a single Agent in ZeptoMail, along with the associated templates and webhooks.
You can view the progress of your data migration in the migration window. This section lists migration activity from the past 30 days.
Troubleshooting migration issues
In some cases, you may encounter errors during migration. The table below lists common issues and their resolutions:
| Error/failure message | Resolution | |
| General errors | Data already exists | Check for duplicates or update the existing record and try again. |
| Invalid value | Occurs when some templates or webhooks contain formats that maybe valid, but are restricted by ZeptoMail. Contact support@zeptomail.com for further clarification. | |
| Threshold reached | The maximum number of API requests allowed, has been reached. Wait for 15–30 mins and retry. | |
| Max limit exceeded | The template storage limit has been reached. Delete any unused migrated data and try again. | |
| Records already exist | Check for duplicates or update the existing record and retry. | |
| Template-related errors | You have reached the maximum limit for creating message templates | Delete unused templates or contact support@zeptomail.com. |
| Message template alias already exists | Use a different template name or update the existing template alias. | |
| Template addition failed | Occurs if the template size or format exceeds the permissible limit or any undefined issue that prevents the template from being migrated. Contact support@zeptomail.com if the issue persists. | |
| Template size limit exceeded | Reduce the template size by removing attachments or minimizing template content and retry. The maximum template size is 5KB. | |
| Template not found | Check your Resend account for the right template and retry. | |
| Webhook-related errors | URL cannot be reached | Ensure the Webhook URL is active and retry. |
| Invalid URL | Ensure the Webhook URL is well formatted and retry. | |
| URL already exists | Remove duplicates or update the existing webhook. |
Domain verification
Before sending emails through ZeptoMail, you must verify the domain(s) migrated from Resend. Domain authorization is specific to each email service provider. DNS records added for Resend authorize only Resend's infrastructure and cannot be reused for ZeptoMail.
ZeptoMail requires new DKIM and CNAME records to be added to your domain's DNS.
To verify your domain:
- In the domain verification page of your ZeptoMail account, choose your DNS provider from the Select your DNS provider drop-down. If your DNS provider is not listed, select Other from the drop-down.
- Copy the DKIM and CNAME values.
- Log in to your respective DNS provider.
- Add the copied DKIM and CNAME records.
- Return to ZeptoMail and click Verify.
Once verified, the domain will be ready to send emails.DNS record updates can take up to 48 hours depending on the DNS provider. If you do not have access to the DNS Manager, click Share records with colleague to email the records to your IT admin.
Setting up email-sending
ZeptoMail supports both SMTP and API-based email sending.
SMTP configuration
| SendGrid | ZeptoMail | |
| SMTP end-points | smtp.resend.com | smtp.zeptomail.com |
| Supported ports | 587,25,2525,465 | 587(TLS), 465(SSL) |
| Password / Auth | Your Resend API key | Your ZeptoMail Send Mail Token |
To configure SMTP:
- Choose the Agent that you want to connect with your ZeptoMail account.
- Navigate to the SMTP/API section and go to the SMTP tab.
- Copy the SMTP credentials to your application to start sending out emails.
API Configuration
Each Agent in ZeptoMail has a unique API token, also known as the Send Mail Token, that separates the Agents from one another. This is the ZeptoMail equivalent of a Resend API key.
To access the Send Mail Token:
- Choose the Agent that you want to connect with your ZeptoMail account.
- Navigate to the SMTP/API section and go to the SMTP tab.
- Copy the SMTP credentials to your application to start sending out emails.
Email tracking
You can enable open and click tracking for individual Agents. To enable tracking:
- Go to the required Agent.
- Navigate to Email tracking.
- Enable tracking as needed.
Refer to this help document to learn more about email tracking in Zoho ZeptoMail.
Points to note
After completing the migration, it is recommended to:
- Send test emails to confirm successful delivery.
- Monitor reports and suppression activity.
- Keep note of the tracking activity.
- Resend's React Email templates are HTML-based and can be re-imported or re-created in ZeptoMail's template editor.