Understanding Metrics
Synapse tracks every email from the moment it's queued through delivery, opens, clicks, and bounces. This guide explains what each metric means and how to interpret the numbers.
Email Lifecycle
Every email goes through a series of statuses. Here's the full lifecycle:
| Status | Description |
|---|---|
| Queued | Email is prepared and waiting to be sent |
| Sent | Email has been handed off to the email delivery provider |
| Delivered | Email has been accepted by the recipient's email server |
| Opened | Recipient opened the email (tracked via a transparent pixel) |
| Clicked | Recipient clicked a link in the email |
| Bounced | Email could not be delivered to the recipient (hard bounce) |
| Complained | Recipient marked the email as spam |
| Failed | An error occurred during sending (provider error, template error, etc.) |
| Suppressed | Email was not sent because a required template variable was missing or recipient is on provider suppression list |
An email can progress through multiple statuses. For example, an email might go from Queued to Sent to Delivered to Opened to Clicked. The status shown is the latest in the chain.
Core Metrics
Sent
The total number of emails successfully handed off to the email delivery provider. This is your baseline for calculating other rates.
Delivered
Emails confirmed as received by the recipient's email server. A high delivered count relative to sent count means your sender reputation and email configuration are healthy.
Delivery Rate
Delivery Rate = Delivered / Sent
| Range | Assessment |
|---|---|
| 95-100% | Excellent -- your list is clean and sender reputation is strong |
| 90-95% | Good -- some bounces, but within normal range |
| Below 90% | Needs attention -- review bounces and clean your contact list |
Opens
The number of unique recipients who opened the email. Opens are tracked using a small transparent image (tracking pixel) embedded in the email.
Open tracking is not 100% accurate. Some email clients block tracking pixels by default (especially Apple Mail Privacy Protection). Your actual open rate may be higher than reported. Some privacy features may also inflate opens by pre-loading images.
Open Rate
Open Rate = Opened / Delivered
| Range | Assessment |
|---|---|
| 25%+ | Excellent for transactional emails |
| 15-25% | Good for notifications |
| 10-15% | Average for promotional emails |
| Below 10% | Consider improving subject lines or targeting |
Clicks
The number of unique recipients who clicked at least one link in the email. Links are automatically tracked by routing through a redirect URL.
Click-Through Rate (CTR)
CTR = Clicked / Delivered
| Range | Assessment |
|---|---|
| 5%+ | Excellent |
| 2-5% | Good |
| 1-2% | Average |
| Below 1% | Review your call-to-action and content relevance |
Bounces
Emails that could not be delivered. Bounces fall into two categories:
| Type | Description | Action |
|---|---|---|
| Hard bounce | Permanent failure -- the email address doesn't exist or the domain is invalid | Contact is automatically unsubscribed to protect your sender reputation |
| Soft bounce | Temporary failure -- mailbox full, server temporarily unavailable | Synapse retries delivery automatically |
Bounce Rate
Bounce Rate = Bounced / Sent
| Range | Assessment |
|---|---|
| Below 2% | Healthy |
| 2-5% | Monitor -- may need list cleaning |
| Above 5% | Action needed -- high bounce rates damage sender reputation |
Suppressed
Emails that were not sent because a template variable marked as required had no value. This is a safety feature -- it prevents sending incomplete or confusing emails to contacts.
A high suppression rate usually means your application isn't sending all the expected data with events. Check with your development team to ensure event attributes are complete.
Dashboard Summary
The main dashboard shows aggregate metrics across all flows for a selected time period:
| Card | Shows |
|---|---|
| Total Sent | All emails sent in the period |
| Average Open Rate | Open rate across all emails |
| Average CTR | Click-through rate across all emails |
| Active Flows | Number of flows currently in Active status |
The time-series chart below the cards shows daily email volume and engagement trends.
Interpreting Your Data
High delivery, low opens
Your emails are getting through but not being opened. Consider:
- Improving subject lines to be more compelling
- Sending at different times of day
- Making sure emails are relevant to the audience (use segments)
High opens, low clicks
People are reading your emails but not taking action. Consider:
- Making your call-to-action more prominent
- Reducing the number of links (focus on one clear action)
- Improving the relevance of the linked content
Rising bounce rate
Your contact list may have quality issues. Consider:
- Checking for recently imported contacts with invalid emails
- Reviewing your event ingestion to ensure valid email addresses
- Setting up segments that exclude contacts without verified emails
Track metrics over time, not just single snapshots. A sudden change in any metric usually points to a specific cause -- a new flow, a data issue, or a change in sending volume.