Understanding Your Metrics¶

Email metrics can be confusing — especially if you're sending to a small list for the first time. This page explains what each number actually means, what "good" looks like, and the caveats you need to know.

The Metrics That Matter¶

Open Rate¶

What it measures: The percentage of delivered emails where the tracking pixel was loaded.

Formula: Unique opens ÷ Delivered × 100

What it really tells you: How effective your subject line and sender name are at getting people to look at your email. A high open rate means people recognize you and find your subject lines compelling.

Apple Mail Privacy Protection

Since iOS 15, Apple Mail pre-fetches email content — including tracking pixels — even if the subscriber never actually reads your email. This means open rates are inflated for subscribers using Apple Mail.

There is no reliable way to distinguish a real open from an Apple Mail pre-fetch. For this reason:

Don't obsess over open rate as an absolute number
Do use it for relative comparisons (Campaign A vs. Campaign B)
Click rate and CTOR are more reliable indicators of actual engagement

If a large portion of your subscribers use Apple devices (common for indie iOS developers), expect your open rates to appear higher than they truly are.

Click Rate¶

What it measures: The percentage of delivered emails where the subscriber clicked at least one link.

Formula: Unique clicks ÷ Delivered × 100

What it really tells you: How engaging your email content is. Unlike opens, clicks require deliberate action — a subscriber chose to follow a link you provided. This makes click rate one of the most trustworthy engagement metrics.

Click-to-Open Rate (CTOR)¶

What it measures: Among subscribers who opened, what percentage clicked.

Formula: Unique clicks ÷ Unique opens × 100

What it really tells you: How well your email content delivers on the promise of your subject line. If your open rate is high but CTOR is low, your subject line is working but the email body isn't compelling enough.

Tip

CTOR is the best metric for evaluating your email content in isolation. Open rate reflects your subject line; click rate reflects both. CTOR isolates the content quality.

Delivery Rate¶

What it measures: The percentage of sent emails that were accepted by the receiving mail server.

Formula: Delivered ÷ Sent × 100

What it really tells you: How clean your subscriber list is. A healthy list should have a delivery rate above 95%. If it drops below that, you likely have stale or invalid email addresses.

Bounce Rate¶

What it measures: The percentage of sent emails that bounced (could not be delivered).

Formula: Bounced ÷ Sent × 100

What it really tells you: How many invalid addresses are on your list. MailJawn only counts hard bounces — permanent delivery failures where the address doesn't exist or the server permanently rejects the message.

Complaint Rate¶

What it measures: The percentage of recipients who marked your email as spam.

Formula: Complained ÷ Sent × 100

What it really tells you: Whether your subscribers actually want to hear from you. This is the most important metric for your sender reputation.

Warning

Keep your complaint rate below 0.1% (1 complaint per 1,000 emails). Major email providers like Gmail monitor complaint rates and will throttle or block your sending if this number climbs too high.

What "Good" Looks Like¶

Industry benchmarks vary wildly by audience size, niche, and sending frequency. Here's a rough guide calibrated for indie mobile developers with small lists (under 10,000 subscribers):

Metric	Healthy	Watch Out	Take Action
Open Rate	30–60%	20–30%	Below 20%
Click Rate	3–8%	1–3%	Below 1%
CTOR	10–25%	5–10%	Below 5%
Delivery Rate	Above 98%	95–98%	Below 95%
Bounce Rate	Below 1%	1–2%	Above 2%
Complaint Rate	Below 0.05%	0.05–0.1%	Above 0.1%

Note

Small lists tend to have higher engagement than large ones. If you have 200 subscribers who all opted in through your app, a 50% open rate is completely normal. Don't compare yourself to mass email senders with millions of subscribers.

Why Your Numbers Might Be Higher (or Lower) Than Expected¶

Higher open rates than expected?

Apple Mail Privacy Protection inflating your numbers (see warning above)
Small, highly engaged list — this is a good thing
Subscribers genuinely interested in your niche

Lower open rates than expected?

Sending too frequently — subscribers tuning out
Subject lines that don't connect with your audience
Emails landing in the Promotions tab (Gmail) or Other (Outlook)

High opens but low clicks?

Your email content doesn't match the subject line's promise
No clear call to action — subscribers read but don't know what to do next
Links buried too far down in the email

Bounces vs. Complaints: What's the Difference?¶

These are often confused, but they mean very different things:

	Bounce	Complaint
What happened	The email could not be delivered	The subscriber reported your email as spam
Who caused it	The receiving mail server rejected the message	The subscriber clicked "Report Spam" in their email client
What it means	The email address is invalid or the mailbox is full	The subscriber does not want your emails
MailJawn's response	Marks subscriber as bounced, suppresses future sends	Marks subscriber as complained, permanently suppresses
Can be reversed?	Yes — bounced subscribers can be reactivated if the issue is resolved	No — complained subscribers cannot be reactivated

Tip

A few bounces are normal, especially after a CSV import. But complaints are a serious signal. If you see complaints, review your sending practices — are you emailing people who didn't explicitly opt in?

Healthy List Indicators¶

Here's a quick checklist for a healthy subscriber list:

Delivery rate above 98% — Your list is clean and addresses are valid
Complaint rate below 0.05% — Subscribers want to hear from you
Bounce rate below 1% — No significant stale addresses
Unsubscribes under 1% per campaign — Content matches expectations
Consistent open rates — No sudden drops suggesting deliverability issues

Deliverability Health Thresholds¶

MailJawn monitors your bounce and complaint rates and flags potential issues:

Bounce Rate¶

Status	Rate	What It Means
Healthy	Below 2%	No concerns
Warning	2% – 5%	Review your import sources and list hygiene
Review	5% – 10%	Clean your list — remove inactive subscribers
Paused	Above 10%	Sending may be restricted to protect your reputation

Complaint Rate¶

Status	Rate	What It Means
Healthy	Below 0.05%	No concerns
Warning	0.05% – 0.1%	Monitor closely
Review	0.1% – 0.5%	Review your opt-in process and sending frequency
Paused	Above 0.5%	Sending may be restricted

For more on managing deliverability, see Deliverability.

Tips for Improving Your Metrics¶

Write subject lines like a human — Skip clickbait. Subscribers from your app already know you. Be direct: "Version 2.3 is live — here's what's new."
One clear call to action — Don't give subscribers five things to click. Focus each email on one goal.
Send consistently — Whether it's weekly or monthly, stick to a schedule. Irregular sending leads to forgotten subscriptions and complaints.
Clean your list periodically — Remove subscribers who haven't opened in 6+ months. A smaller, engaged list outperforms a large, disengaged one.
Use segments and tags — Send relevant content to relevant people. A subscriber interested in SwiftUI tips may not care about your Android roadmap.
Watch trends, not single campaigns — One campaign with a low open rate isn't a crisis. Three in a row is a pattern worth investigating.