Why validate emails?
Sending to invalid, disposable, or non-existent email addresses wastes resources and damages your sender reputation. Every bounce counts against you with email providers like Gmail and Outlook. SendKit’s email validation lets you verify addresses before you send — catching bad emails before they become bounces.What gets checked
Each validation runs multiple checks and returns a confidence level (HIGH or LOW) for each:
| Check | What it detects |
|---|---|
| Syntax | Whether the email format is valid (e.g., missing @, invalid characters) |
| DNS | Whether the domain has valid MX records that can receive email |
| Mailbox | Whether the specific mailbox exists on the mail server |
| Role address | Whether it’s a group address like info@, admin@, or support@ |
| Disposable | Whether it’s from a disposable/temporary email service like Mailinator or Guerrilla Mail |
| Random input | Whether the local part of the email appears to be randomly generated characters |
Reading the results
Every validation returns a clear verdict:is_valid— Overall validity (HIGH= safe to send,LOW= risky)should_block— Boolean recommendation on whether to block the addressblock_reason— If blocked, the specific reason why:
| Block reason | Meaning |
|---|---|
invalid_syntax | The email format is malformed |
invalid | The email is invalid or undeliverable |
disposable_email | It’s a throwaway address |
Using validation
From the dashboard
Go to Email Validation in the sidebar, enter an email address, and get instant results. Your validation history is saved so you can review past checks.From the API
Validate an email programmatically via the API. The response includes all evaluation fields so you can make your own decisions about what to block.Automatic validation on send
SendKit also validates recipients automatically when you send an email. If a recipient has invalid syntax or uses a disposable domain, the email is blocked before it’s sent — protecting your reputation without any extra code.Automatic validation on send uses local checks only (syntax, disposable). It doesn’t consume credits. Credit-based validation via the API or dashboard includes deeper checks like DNS, mailbox verification, and more.
Credits
Each email validation costs 1 credit. You can purchase credit packages from the dashboard under Settings > Billing.- Credits are shared across your team
- Validations from both the dashboard and API consume credits
- If you run out of credits, the API returns a
402error
Auto-reload
You can configure auto-reload to automatically purchase more credits when your balance drops below a threshold. Set this up in Settings > Billing to avoid interruptions.Smart caching
SendKit caches validation results to save credits and speed up repeated lookups:| Result | Cache duration |
|---|---|
| Valid email | 90 days |
| Invalid email | 180 days |
| Disposable | Forever |
FAQ
Does sending an email consume a validation credit?
Does sending an email consume a validation credit?
No. Automatic validation during email sending uses local checks and is free. Only explicit validation requests (via API or dashboard) consume credits.
What's the difference between local and full validation?
What's the difference between local and full validation?
Local validation checks syntax and disposable status using SendKit’s own systems. Full validation (API/dashboard) additionally checks DNS records, verifies whether the mailbox actually exists on the mail server, and detects role addresses.
Should I validate every email before sending?
Should I validate every email before sending?
For transactional emails to known users (e.g., password resets), it’s usually not necessary — SendKit’s automatic checks handle bad addresses. For marketing campaigns or new signups, validating upfront helps reduce bounce rates significantly.
Can I validate emails in bulk?
Can I validate emails in bulk?
Currently, the API validates one email per request. You can send multiple requests in parallel for bulk validation.