Keep legacy email clients working with Exchange Online.
lette.io proxies IMAP and SMTP traffic from legacy email clients and devices, while handling modern authentication with Exchange Online securely in the background.
lette.io proxies IMAP and SMTP traffic from legacy email clients and devices, while handling modern authentication with Exchange Online securely in the background.
A simpler, more secure way to support legacy email clients — without running your own mail servers.
lette.io keeps all email fully inside Microsoft 365 while enabling legacy clients and devices to authenticate and communicate securely using IMAP and SMTP.
All email is sent, received, stored, and audited in Microsoft 365. lette.io modernizes access and authentication without replacing your system.
Avoid running secondary mail servers or custom IMAP proxies. No patching, monitoring, backups, or capacity planning.
Works with your existing tenant, identities, and mail flow. No migrations or mailbox moves required.
Compatible with legacy email apps, printers, scanners, and embedded devices using SMTP and IMAP, including implicit TLS and STARTTLS.
SMTP support was introduced proactively to align with Microsoft’s Basic Auth deprecation in March 2026.
Retention, journaling, eDiscovery, audit logs, and DLP continue to function normally because email never leaves Microsoft 365.
Get production-ready in minutes instead of engineering and maintaining custom SMTP relays or IMAP proxy infrastructure.
No setup fees. Scale up or down anytime. Charges are prorated automatically. Cancel anytime.
Need pricing for a larger number of mailboxes or a dedicated proxy instance? Are you interested in becoming a reseller? Contact us.
01
Grant lette.io access to authenticate users securely in your Microsoft 365 environment.
02
Select which mailboxes should be accessible through legacy IMAP and SMTP clients.
03
Point email apps, printers, or scanners to lette.io — Exchange Online stays the system of record.
Start your free 14-day trial — no setup fees, cancel anytime.