How can we help?
Search guides for sender-risk controls, domain authorization, delivery events, setup, troubleshooting, and billing.
Popular searches
Email API
Send your app’s transactional email over REST or SMTP, with SDKs for JavaScript, Python, and PHP, framework transports, and signed delivery webhooks. Scale to multi-tenant sending with sub-accounts.
Quickstart
Send your first email in minutes — create an API key, authorize your domain, and make your first API call.
Webhooks
Turn delivered, hard-bounced, soft-bounced, complained, and unsubscribed events into sender-risk signals.
Set up SPF and DKIM for sending
Authorize sending domains so MailChannels can protect shared reputation.
Send vs Send Async
Choose the right send path for latency, throughput, event visibility, and operational control.
Outbound Filtering
A cloud-based filter for outbound email that blocks spam and abuse before it leaves your mail servers, protecting your sending reputation and deliverability.
Set up outbound filtering
Connect your mail server to MailChannels and start filtering outbound email in a few steps.
SMTP error reference
Look up MailChannels bounce codes — ESA, CS, RBL, IRR, and more — and find out how to resolve each one.
Unblock senders
How to locate a blocked sender in Log Search, delist an ESA block, and report false positives.
Set up SPF records
Add MailChannels to your domain’s SPF record and configure Domain Lockdown to prevent spoofing.
Inbound Filtering
Inbound filtering for hosting providers — block spam, phishing, and malware before they reach hosted inboxes, enforce authentication standards, with self-service quarantine and per-domain controls that keep your support team out of the loop.
Set up inbound filtering
Provision your first domain, prepare your mail servers, and route inbound traffic through MailChannels.
Safelists and blocklists
Allow or block specific senders, domains, and IP addresses across your entire network or per domain.
Quarantine management
Review quarantined messages, release false positives, and configure quarantine delivery schedules.
Domain admin guide
Set up per-domain filtering preferences, user access, and quarantine settings as a domain administrator.