Bridges

A Bridge is the endpoint your application sends transactional email through. You manage Bridges under Transactional → Bridges.

Each Bridge has:

• Its own credentials: an SMTP username and password, and a One Connect Key for the HTTP sending API.
• One pool, chosen when you create it. Every message sent through the Bridge leaves from that pool's IPs.
• Its own tracking switches: Track Opens and Track Clicks.
• Its own sending stats: total sent, delivered, bounced and complaints.

Because every Bridge has separate credentials, the usual approach is one Bridge per application: one for your shop's order emails, one for your app's password resets, one for your support tool. If one application's credentials leak, you delete that Bridge and the others keep sending.

Before you create a Bridge

Add and verify the domain you'll send from under Setup → Sending Domains. A Bridge can send from any of your verified domains, but it can't send from a domain that isn't verified. See Sending Domains.

The Bridges page

Go to Transactional → Bridges. Above the table are two buttons:

• Create a Bridge opens the form for a new Bridge.
• Export all downloads the credentials of every Bridge as one CSV file. It appears once you have at least one Bridge.

The table lists your Bridges:

Column	What it shows
SMTP Name	The Bridge's name. Click it to open the Bridge's details.
Assigned Pool	The pool the Bridge sends through. If the pool is active, click it to see the pool's IPs.
Track Opens	Switch open tracking on or off for this Bridge.
Track Clicks	Switch click tracking on or off for this Bridge.
Created On	When the Bridge was created.
Sending Stats	Click the chart icon to see this Bridge's totals.
Status	Enable or disable the Bridge. A Bridge suspended by our team shows Suspended instead.
Actions	View SMTP Details, Rename, Download SMTP Credentials and Delete.

Create a Bridge

1. Go to Transactional → Bridges and click Create a Bridge.

2. Fill in the form:

   Field	What to enter
   Name	A name you'll recognise, such as Order emails or Password resets. It's for your reference only and isn't shown to recipients.
   Pool	The pool this Bridge's mail should leave from. Your own pools are listed under Dedicated Pools. Pools that Mumara ONE manages for your account are listed under Shared Pools.

3. Click Create.

The credentials appear straight away in the same window, under Method 1: Send via SMTP and Method 2: Send via API. You can copy them now or come back to them at any time from the Bridge's details page. Click Close when you're done.

Choose the pool carefully

A Bridge's pool is fixed once the Bridge is created. To move an application to another pool, create a new Bridge on that pool, switch the application to the new credentials, then delete the old Bridge.

The credentials a Bridge generates

Mumara ONE generates the credentials for you. You can't choose them.

Credential	Used for	Notes
Host	SMTP	The relay host your application connects to. It's the same for every Bridge.
Port	SMTP	Shown as 587. Other ports are listed in SMTP Settings.
Encryption	SMTP	Shown as TLS: use STARTTLS on port 587.
Username	SMTP	A long generated string that identifies the Bridge. Copy it exactly, with no spaces.
Password	SMTP	The Bridge's password.
One Connect Key	HTTP sending API	Sent as a Bearer token in the Authorization header. Treat it as a password.

The SMTP credentials and the One Connect Key belong to the same Bridge. They share its pool, tracking switches and stats, and deleting the Bridge revokes both.

Rotating credentials

There's no button to regenerate a Bridge's password. To rotate credentials, create a new Bridge on the same pool, update your application, check that mail is flowing, then delete the old Bridge.

View a Bridge's details

Click the Bridge's name, or open the Actions menu and choose View SMTP Details. The page is titled One Connect Bridges for followed by the Bridge's name, and has two panels.

Method 1: Send via SMTP shows:

• Name, Host, Username, Password, Port and Encryption, each with a copy button where it's useful.
• The Track Opens and Track Clicks switches for this Bridge.
• Download SMTP Credentials, which saves the SMTP settings as a CSV file.

Method 2: Send via API shows:

• The One Connect Key, labelled Bearer Authorization, with a copy button.
• Sample requests on the Payload, cURL, PHP, NodeJS, Python and Bash tabs. On the Payload tab, the Content Type selector switches between the multipart/form-data and application/json versions of the request body.
• An API Documentation link.

The Sending API page describes every request field and response.

Rename a Bridge

1. In the Bridges table, open the Bridge's Actions menu and choose Rename.
2. In the Rename Bridge dialog, enter the new name, up to 100 characters.
3. Confirm. You'll see "Bridge renamed."

The name is only a label for you. The Bridge keeps its credentials, pool, tracking switches and stats, so your application doesn't need any change. A suspended Bridge can't be renamed.

Open and click tracking

Every Bridge has its own Track Opens and Track Clicks switches. You'll find them in the Bridges table and on the Bridge's details page. Both are off for a new Bridge.

Switch	What Mumara ONE does to each message
Track Opens	Adds a 1×1 tracking image just before the closing </body> tag of the HTML part.
Track Clicks	Rewrites every http:// and https:// link in an <a href="..."> tag of the HTML part, so a click passes through a tracking address before reaching the original URL.

A few things to know:

• Only the HTML part is tracked, and the AMP for Email part if there is one. Plain-text messages, and the plain-text part of a multipart message, are sent unchanged.
• The AMP part is tracked over HTTPS, with the tracking image added as an amp-img. See Tracking in the AMP version.
• Open tracking needs a </body> tag. An HTML part without one can't carry the tracking image.
• Changes apply to messages sent after you flip the switch. Messages already sent aren't changed.

The tracking note

On the Bridge's details page, this note is shown whenever Track Opens or Track Clicks is on, and hidden when both are off:

Opens and clicks are tracked for mail sent From one of your verified sending domains with tracking on. A domain without its own tracking domain uses the default one.

Tracked links and the tracking image are served from the tracking domain of the sending domain in the From address. The Bridge's switches decide whether a message is tracked; the sending domain decides where the tracking links point. So, before relying on tracking:

1. Go to Setup → Sending Domains and open the domain you send from.
2. Make sure its tracking domain is enabled and verified, so links point at your own domain rather than the default one.

If tracking is switched off for that sending domain, messages from it are sent without tracking, whatever the Bridge's switches say. See Sending Domains.

Leave click tracking off for security emails

Password resets, sign-in links and one-time codes work best untracked. A rewritten link looks different from the one your application generated, and some security-conscious recipients and mail filters are wary of it. Many teams keep a separate Bridge, with tracking off, for this kind of email.

Dedicated Pools

The pool a Bridge sends through determines which IPs its mail leaves from.

• On plans with dedicated infrastructure, the Pool list shows your own Dedicated Pools. Binding a Bridge to its own pool keeps its reputation separate: a marketing campaign sent from another pool can't affect it.
• On other plans, the list shows the shared pool Mumara ONE manages for your account, and your mail is sent from shared infrastructure.

You create and manage pools, and assign Dedicated IPs to them, under Setup → Dedicated Pools. See Dedicated Pools. Several Bridges can share one pool.

Delete a pool's Bridges first

A Dedicated Pool that still has Bridges can't be deleted: the message names the Bridges in the way. A Bridge can't be moved to a different pool, so move the applications using them to Bridges on another pool, delete the old Bridges, then delete the pool.

Enable or disable a Bridge

Use the Status switch in the Bridges table to pause a Bridge without deleting it.

• Off: the relay rejects every message sent through the Bridge with an error saying the bridge is disabled. The credentials still exist.
• On: the Bridge accepts messages again with the same credentials.

This is useful when you suspect an application is misbehaving and want to stop its mail while you investigate.

If a Bridge shows Suspended instead of a switch, our team has suspended it. The relay rejects its messages, its Actions menu is hidden, and you can't switch it back on yourself. Contact Mumara support to find out why and have it restored.

Sending stats

Click the chart icon in the Sending Stats column to see the Bridge's running totals, in a window titled with the Bridge's name:

Figure	Meaning
Total Sent	Messages that reached a final result: delivered plus bounced.
Total Delivered	Messages the receiving mail server accepted.
Total Bounced	Messages the receiving mail server rejected.
Total Complaints	Recipients who reported a message as spam, where the mailbox provider reports it back.

For individual messages, delivery logs and filtering by date, use Analytics.

Download and export credentials

There are two ways to save credentials to a file:

Action	Where	File contents
Download SMTP Credentials	The Bridge's Actions menu, or its details page	One Bridge: Host, Username, Password, Port and Encryption. The file is named after the Bridge, for example Order-emails-credentials.csv.
Export all	Above the Bridges table	Every Bridge: Bridge Name, Pool Name, SMTP Host, SMTP Username, SMTP Password, SMTP Port and API Key.

These files contain passwords

Both files hold working credentials in plain text. Store them like any other secret, and delete copies you no longer need.

Delete a Bridge

1. In the Bridges table, open the Bridge's Actions menu and choose Delete.
2. Confirm when asked Do you want to delete this Bridge?

Deleting a Bridge revokes its SMTP credentials and One Connect Key straight away. Any application still using them gets authentication errors and stops sending. Deleting can't be undone: if you need the Bridge again, create a new one and update your application with the new credentials.

How many Bridges you can have

The number of Bridges you can create depends on your plan. The Bridges row on the Dashboard shows how many you've created and how many your plan allows. See Dashboard and Plan and Usage.

When you reach the limit shown on the Dashboard, Create a Bridge refuses with a message instead of creating another one. Delete a Bridge you no longer need, or move to a plan that allows more. See Mumara ONE pricing for what each plan includes.

Troubleshooting

Problem	What to check
The Pool list is empty	Your account has no active pool to bind to. On plans with dedicated infrastructure, create a pool under Setup → Dedicated Pools first. Otherwise, contact Mumara support.
The Bridge isn't created	Make sure you entered a Name and picked a Pool, and that you haven't reached your plan's Bridge limit.
Messages aren't tracked	Check the Bridge's Track Opens and Track Clicks switches, then check that the From address is on one of your verified sending domains with tracking on. Only HTML messages are tracked.
A pool can't be deleted because it "still has Bridges"	Move the applications using the named Bridges to Bridges on another pool, delete the old Bridges, then delete the pool.
The application gets authentication errors	The Bridge may have been deleted or disabled, or the username or password wasn't copied exactly. See SMTP Settings.