AT&T retired its txt.att.net and mms.att.net email-to-text gateways — the carrier email-to-SMS gateway IT teams relied on for years — on June 17, 2025. If your monitoring stack, on-call rotation, or alerting scripts route text messages through AT&T's email gateway, those alerts have already stopped being delivered — silently. This page explains what breaks, how to audit your exposure, and the honest replacement options.
Last updated: 2026-06-13
No. txt.att.net and mms.att.net — AT&T's email-to-text gateways, also known as the AT&T SMS gateway — were shut down on June 17, 2025 and no longer deliver. Emails sent to number@txt.att.net or number@mms.att.net are accepted upstream and then silently dropped: no text arrives and no bounce is returned. Because AT&T controls the domains, there is no forwarding workaround — the address has to be changed at the source. SigSpan is a drop-in replacement that keeps those alerts delivering without changing how your tools send email.
For decades, IT teams have routed text alerts by emailing 5551234567@txt.att.net — no SMS provider, no SDK, no contract. AT&T offered the gateway as a courtesy, never as a contracted service. On June 17, 2025, that gateway went away.
The teams affected are the ones who built operational messaging around the gateway and largely forgot about it: monitoring stacks paging on-call engineers, cron jobs and runbooks that text via mail or sendmail, and inventory systems that store an AT&T gateway address as a contact method. AT&T owns the domain, so there is no customer-side migration path — the addresses simply stopped working on the effective date.
AT&T's shutdown was part of the wider carrier retirement. T-Mobile shut down tmomail.net in December 2024, and Verizon has scheduled vtext.com for March 31, 2027. If you have not already migrated off txt.att.net, those alerts are dark right now.
A reasonable starting point is to check your environment and any alerting equipment — room-temperature sensors, UPS units, generator monitoring, and similar devices — that has an email address pointing to a phone number at @txt.att.net or @mms.att.net.
You can no longer address an email to a phone number on the AT&T network. Any device, script, or monitoring tool still configured to send to one of those addresses needs its destination updated to a real text-message path — otherwise the alerts simply stop arriving.
Because the failure is silent — no bounce, no error — the only reliable way to find your exposure is to search for the AT&T gateway domains directly. The two retired domains are txt.att.net (SMS) and mms.att.net (MMS). Work through these in order:
# Search common locations for AT&T gateway addresses grep -rInE '@(txt|mms)\.att\.net' /etc /opt /home /var/spool/cron 2>/dev/null # Check the current user's crontab crontab -l | grep -E '@(txt|mms)\.att\.net'
Anything you find is a silent failure today. Update each destination to a real text-message path before you consider the migration complete.
The AT&T email-to-text retirement is not limited to the main AT&T brand. Cricket Wireless, FirstNet, and AT&T Prepaid all run on AT&T's network, and the same move away from unauthenticated carrier gateways applies across those brands. If any of your alerts route through an AT&T-network number, treat the carrier email-to-text path as unreliable regardless of the brand on the plan.
Some of these brands historically used their own gateway domains rather than txt.att.net. If you have alerts addressed to a brand-specific gateway, audit those addresses the same way — confirm delivery with a low-volume test message, and do not assume a brand gateway still works just because it has not been formally announced as retired.
We track carrier and sub-brand gateway changes as we can verify them against official sources. If you have documentation on a specific brand gateway's status, email admin@sigspan.com and we will add it.
There are three honest categories of replacement, each with real tradeoffs:
Maximum flexibility, but every piece is yours to build and maintain. Standing up a direct SMS API means writing the email parser, deduplication, rate limiting, on-call routing, opt-out handling, and audit logging yourself — an engineering project, not a configuration change. The right answer only if you have spare engineering capacity and unusual requirements.
Comprehensive on-call platforms with schedules, escalations, and incident timelines. They do far more than replace an SMS gateway — and you pay for all of it. If your only need is to get alert emails delivered as text messages, this is usually overkill, and the pricing reflects the much broader platform you would not be using.
A drop-in replacement that preserves your existing email-based integration pattern. The only change is pointing your alerting mechanism at your unique SigSpan email address — your monitoring tools keep sending email exactly as they do today, and SigSpan handles the parsing and text delivery. No code changes, no new integrations, and nothing else in your environment changes, which makes it the lowest-migration-cost option for teams whose only goal is to keep existing alerts flowing.
SigSpan is a drop-in replacement — your monitoring tools keep sending email, SigSpan handles the text delivery. No SDK, no code changes, no new integrations. Free trial, no card required.
AT&T retired its email-to-SMS gateway on June 17, 2025. As of that date, messages sent to number@txt.att.net no longer deliver. There was no grace period — delivery stopped on the effective date.
Not from AT&T. txt.att.net and mms.att.net were the AT&T SMS gateways (the carrier email-to-SMS and email-to-MMS gateways), and AT&T shut them down on June 17, 2025 with no replacement address — "AT&T SMS gateway," "email-to-text gateway," and "txt.att.net" all refer to the same retired service. Delivering text alerts to AT&T numbers now requires a registered A2P sender rather than the old gateway domain. SigSpan provides that while keeping your existing email-based alerts unchanged.
Yes. AT&T retired both gateways together on the same date — txt.att.net (SMS) and mms.att.net (MMS) both stopped delivering on June 17, 2025. If any of your alerts route to mms.att.net for image or longer-message delivery, they are affected too.
No. AT&T owns the txt.att.net and mms.att.net domains and controls their MX records. With the gateway retired there is no DNS-level or SMTP-level forwarding option available to customers. The addresses have to be changed at the source — in your monitoring config, your scripts, and your device inventory.
If you send application-to-person SMS through a US long code, yes — A2P 10DLC registration is required by the carriers, not by the SMS provider. Your replacement provider handles the registration mechanics, but you supply brand and campaign details. Registration typically takes days to weeks, so start it before your cutover. Toll-free and short codes follow separate registration processes.
Inventory first: check your monitoring config, scripts, and any alerting equipment — temperature sensors, UPS units, generator monitoring — for addresses pointing at @txt.att.net or @mms.att.net, so you have a complete list of every reference. With a bridge replacement like SigSpan, the migration is a find-and-replace of the destination address rather than a rewrite — your tools keep sending email, so you change only where the alert is addressed, not how it is generated. Validate end-to-end with low-volume test traffic before cutting over production alerts, and stage the change during a planned maintenance window.
Yes. Because AT&T does not offer a replacement gateway address, an email-to-text bridge is the closest drop-in alternative: you keep sending the same alert email, and the bridge delivers it as a text over a registered A2P sender. That preserves your existing setup — no SDK, no code changes — while restoring delivery to AT&T numbers. Direct SMS APIs and full incident-management platforms also work, but both require more integration than simply repointing an email address. SigSpan is an email-to-text bridge built for exactly this migration.
Treat them as unreliable. Cricket, FirstNet, and AT&T Prepaid all run on AT&T's network, and the industry-wide retirement of unauthenticated carrier gateways applies across AT&T-network brands, not just the main txt.att.net domain. If you route alerts through a brand-specific gateway address, confirm delivery with a low-volume test message and plan to move off it — do not assume a brand gateway still works just because a shutdown has not been separately announced.
Shutdown dates, official sources, and migration guidance for every major US carrier gateway — T-Mobile, AT&T, and Verizon.
Verizon retires vtext.com and vzwpix.com on March 31, 2027. See what breaks and how to replace it before the deadline.
See an error or have a more recent source? Email admin@sigspan.com — we update this page as soon as we can verify changes.