This guide explains the difference between delivery and deliverability, and how each concept applies across email, SMS, and mobile push notifications.
Delivery vs. Deliverability: What’s the Difference?
Although often used interchangeably, these terms mean different things:
Delivery
Delivery refers to whether your message was successfully received by the recipient’s system.
If it fails → it’s due to technical reasons (e.g., invalid number, server issues)
It answers: Did the message arrive?
Deliverability
Deliverability refers to whether your message actually reaches the intended destination (like the inbox instead of spam).
Influenced by reputation, engagement, and content
It answers: Did the message reach where it should?
Deliverability is more complex and plays a bigger role in performance.
How Deliverability vs. Delivery Differs by Channel
Deliverability behaves differently depending on the channel you’re using.
Email: Deliverability Matters the Most
In email, deliverability is the most critical factor affecting performance.
Email Deliverability
Inbox providers decide where your email lands (primary inbox, promotions, or spam) based on:
Sender reputation
Recipient engagement (opens, clicks)
Email content and structure
Poor practices—like spammy subject lines or low engagement—can push emails into spam.
Learn more: What is Sender Reputation and Why It Matters
Email Delivery
Delivery simply means the email was accepted by the recipient’s mail server.
Failures are called bounces:
Soft bounce → temporary issue (e.g., full inbox)
Hard bounce → permanent issue (e.g., invalid email)
Learn more: Email Deliverability FAQs
SMS: Deliverability Works Differently
For SMS, both delivery and deliverability matter—but the concept is different from email.
SMS Deliverability
Deliverability depends on whether carriers allow or filter your message.
Factors include:
Sending number type (short codes are more trusted)
Message content and links
Spam complaints
Whether the recipient has saved your contact
Sending during allowed hours
Carriers may silently filter messages without notifying you.
SMS Delivery
Delivery is confirmed through delivery reports (DLRs).
If a message fails, it could be due to:
Invalid phone number
Network issues
Device being unreachable
Unlike email, SMS failures are not categorized as bounces.
Mobile Push: Delivery Only
Push notifications do not have a deliverability concept.
There is no filtering based on:
Content
Engagement
Reputation
Push Delivery
A push notification is either delivered or not.
Common reasons for failure:
User unsubscribed
App uninstalled
Server issues (APNs or FCM)
Key Differences at a Glance
Channel | Delivery | Deliverability | What Matters Most |
Yes | Yes | Deliverability (inbox placement) | |
SMS | Yes | Yes | Carrier filtering + delivery |
Mobile Push | Yes | No | Delivery only |
Why This Matters
Understanding this difference helps you focus on the right improvements:
For email → optimize reputation, engagement, and content
For SMS → ensure compliance and trusted sending practices
For push → focus on opt-ins and app engagement
Key Takeaway
Delivery ensures your message is sent successfully, while deliverability determines whether it actually reaches your audience effectively. The importance of each varies by channel, with deliverability playing the biggest role in email performance.