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WelcoYour alerts, by text.

Prevent duplicate alert texts on every phone

Welco helps prevent duplicate alert texts, so your team hears about each alarm email once, even when a mail server delivers it twice. Welco tracks every email and every phone, and a retried copy is set aside before it becomes a second text. There is nothing for you to switch on.

Stop double alert textsBook a demo

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  • Nothing to switch on
  • One text per email on each phone
  • Retried copies use no credits

Works by email with

  • Access control
  • Ignition
  • Microsoft 365 / Outlook
  • Nagios

No duplicate texts

Try it: turn it off and on.

2

Without it: one mail retry, two buzzes

1

With it: one email, one text

On. The phone gets 1 text.

With No duplicate texts off, the phone gets 2 texts: Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out. Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out. With it on, it gets 1: Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out.
Animation: No duplicate texts switched off and on. Without it: one mail retry, two buzzes. With it: one email, one text.

What changes for the person on call

  • One buzz per alarm email

    A mail retry at 2 AM no longer wakes someone twice for one alarm.

  • Calm phones in a storm

    Retries pile up when mail servers are busy. During an alarm storm, each phone still sees each email once.

  • Everyone keeps their own copy

    It works per phone. Everyone on a list of several phones still gets the alert.

  • No credits spent on copies

    A set-aside copy is never sent, so it never uses a message credit.

How does Welco prevent duplicate alert texts?

It runs quietly behind Welco's alert feature set. There's no setting to find and nothing to tune.

  1. The email arrives with its Message-ID

    Every email carries a hidden ID called the Message-ID. If one arrives without it, Welco gives it one, so a second copy still matches.

  2. Welco checks each phone on the rule

    It remembers which phones already got a text for that ID. A number listed twice on one rule counts once.

  3. Only new phones are texted

    Phones that already have it are skipped. All of this happens before anything is sent.

A real example: a door alarm delivered twice

An access control server sent its email, timed out waiting for a reply from its mail relay, and sent it again 40 seconds later.

Alert email from access@security.example.com, subject “Door Forced Open - Stair 2”. Welco trims it to one text of 97 characters: “Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out.”

Text received: Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out.

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Animation: the alert email "Door Forced Open - Stair 2" is trimmed into one text: "Welco: [North Bldg] Door forced open, Stair 2 emergency exit at 9:47 PM. Reply STOP to opt out."

Both copies had the same Message-ID. The security lead's phone got one text, and the second copy was set aside. The door forced alarms page covers the setup for these panels.

One alarm email, one text

Sign up and let Welco catch mail retries before they reach your team.

7-day free trial, 15 message creditsCard required for verificationNo charge for 7 daysEmail reminder before billing

Stop double alert textsBook a demo

Which repeats Welco catches, and which start on your side

Some repeats are made before the email reaches Welco. Each of those copies has its own Message-ID, so Welco treats them as separate emails.

A mail server retries after a timeout

Same Message-ID?
Yes
What the phone gets
One text

A busy mail system hands over the same email twice

Same Message-ID?
Yes
What the phone gets
One text

One number appears twice on a rule's phone list

Same Message-ID?
Not needed
What the phone gets
One text

Two Outlook or Exchange forwarding rules send the same alert

Same Message-ID?
No
What the phone gets
Two texts until one rule is removed

A mail group holds your Welco address twice, or nests another group that has it

Same Message-ID?
No
What the phone gets
Two texts until the group is cleaned up

The system sends one email per contact

Same Message-ID?
No
What the phone gets
One text for each email it sends

Fix copies made upstream

When two texts arrive for one alarm, a few minutes with the email headers usually finds the cause.

  • Compare the headers

    Open the full headers of both copies. Different Message-IDs mean the extra copy was made before Welco.

  • Keep one path

    Leave one route from the system to your Welco address and remove the extra forwarding rule or group.

  • Start from a clean forward

    The guide to forwarding Outlook alerts shows a setup with a single path.

Where duplicate protection earns its keep

Frequently asked questions

Why did I get the same alert twice if Welco removes duplicates?

Most likely the copy was made before it reached Welco. Two forwarding rules or a nested mail group create separate emails with different Message-IDs. Compare the headers of both copies and remove the extra path.

Does duplicate protection stop the alert going to my second phone?

No. It works per phone. If you send an alert to three phones, each one gets a single copy. Only a second copy to the same phone is skipped.

Can Welco ignore an alarm that repeats every few minutes?

Not today. Welco removes copies of the same email, but a new email for the same alarm becomes a new text. Use alert rules to drop repeats your system marks clearly, or set the system to send once.

Why would a mail server send the same alert email twice?

Mail servers retry when they don't get a clear answer in time. A slow relay, a busy queue or a dropped connection can leave the sender unsure the first copy landed, so it sends again. Both copies carry the same Message-ID, which is how Welco knows the second one is a repeat.

Do I have to turn duplicate protection on?

No. It applies to every alert email on every account. You won't find a switch for it, and you don't need one.

Is a recovery email treated as a duplicate of the alarm?

No. A recovery is a new email with its own Message-ID, so it becomes its own text. If recoveries shouldn't wake anyone, an alert rule can keep them in email.

Get each alarm once, on every phone

Mail retries happen. Your team only needs to hear about the alarm one time.

Stop double alert textsBook a demo

7-day free trial, 15 message creditsCard required for verificationNo charge for 7 daysEmail reminder before billing