Delivery Events
These events track whether your email was successfully handed off to the recipient’s mail server. Injection (gray) — The email was accepted by Lettr and queued for processing. This is the first event in any email’s lifecycle. If you see an injection event but nothing after it, the email may still be in transit or may have encountered a processing issue downstream. Delivery (green) — The email was successfully delivered to the recipient’s mail server. This is the most positive signal in the pipeline. Keep in mind that delivery confirms the recipient’s server accepted the message — it does not guarantee the email landed in the inbox rather than a spam folder.Engagement Events
These events indicate that the recipient interacted with your email. Opened (blue) — The recipient opened the email. Open tracking works by embedding a small invisible image; when the email client loads that image, the open is recorded. Some email clients block images by default or prefetch them automatically, so open rates are an approximation rather than an exact count. Under the hood, Lettr tracks both the initial open and subsequent opens as separate events, but both are displayed as “Opened” in the dashboard. AMP Opened (blue) — Same as Opened, but for emails delivered in AMP format. AMP emails are interactive and may be tracked slightly differently depending on the receiving mail client. Clicked (indigo) — The recipient clicked a link in your email. Lettr rewrites links to route through its tracking servers, so every click is recorded along with the specific URL that was clicked. Click data is generally more reliable than open data because it requires deliberate user action. AMP Clicked (indigo) — Same as Clicked, but for links within an AMP email.Bounce Events
Bounces mean the email could not be delivered. Understanding the difference between bounce types is critical for list health. Bounced (red) — A general bounce event. Check the Message Details view for the specific bounce reason and whether it was a hard or soft bounce. Hard bounces indicate a permanent failure (the address does not exist or the domain rejects your mail), while soft bounces are typically temporary (the mailbox is full, the server is busy). Bounced (OOB) (red) — An out-of-band bounce. These arrive after the initial delivery appeared successful — the receiving server accepted the message initially, then later determined it could not be delivered and sent a separate bounce notification back. Out-of-band bounces are less common but can be harder to diagnose.Rejection and Failure Events
These events occur before the email reaches the recipient’s mail server. Rejected (orange) — The email was rejected by Lettr’s infrastructure or by a policy rule before delivery was attempted. This could be due to content filtering, rate limits, or a configuration issue on your end. Generation Rejection (orange) — Similar to Rejected, but specifically indicates that the message was blocked during the generation phase — the point where the email is assembled and prepared for sending. Failed (red) — A generation failure. Something went wrong while preparing the message for delivery. This is typically an infrastructure-level issue rather than something caused by your email content.Delay Events
Delayed (yellow) — Delivery to the recipient’s server was temporarily postponed. Lettr will continue retrying automatically. Delays are common with large mail providers that throttle incoming connections. A delayed email will usually resolve on its own — if it does not, it will eventually become a bounce event.Engagement Opt-Out Events
These events track when recipients opt out of receiving your emails. Unsubscribed (purple) — The recipient unsubscribed from your emails. This event covers two distinct mechanisms, both displayed as “Unsubscribed” in the dashboard:- List-Unsubscribe — The recipient used the one-click unsubscribe option built into email standards (the List-Unsubscribe header). Most major email clients surface this as a button in the inbox UI.
- Link Unsubscribe — The recipient clicked an unsubscribe link within the email body.
Complaint Events
Spam (red) — The recipient reported your email as spam. This is one of the most damaging events for your sender reputation. A complaint rate above 0.1% can trigger filtering at major providers. When this event appears, the recipient is immediately suppressed. Review your sending practices and content if you see complaint events appearing regularly.Reading Event Badges in the Dashboard
The badge color gives you an immediate signal about the nature of the event without needing to read the label:- Green — Success (delivered)
- Blue / Indigo — Engagement (opens, clicks)
- Yellow — Temporary issue (deferral)
- Orange — Rejection to investigate
- Red — Serious failure or complaint
- Purple — Recipient opted out
- Gray — Neutral starting point of the email’s journey