Free tool · Inbox Lens
Does your live image actually update?
Put a probe image in a test email, open it in your inboxes, and watch every request arrive. You’ll see which clients fetch it, which proxies stand in for the reader, and which reopens quietly show a cached copy.
Free, no signup. A probe listens for 24 hours.
- Requests
- 0
- From machines
- 0
- Opens, no request
- 0
- Fetched by a browser or inbox
- Fetched by a machine
- You opened it, request arrived
- You opened it, no request
- You opened it, unclear
- Copy under 15 min old
- 15 min or older
An illustrative recorded run, not a measurement. Your own run is the only evidence that counts for your inboxes.
Test your own inboxes
It takes about five minutes, plus a reopen later. Use the inboxes your subscribers actually use.
- 1
Send the probe
Paste its image snippet into a test send from your email platform, so it goes through your real sending setup.
- 2
Open it everywhere
Open it in each inbox, on phone and desktop. Reopen after 30 minutes and again after two hours: cache effects only show up on reopens.
- 3
Mark every open
Press “I just opened it in…” each time. An open that shows a saved copy sends no request, and your press is the only way it reaches the report.
Create a probe
You get an image snippet for a test email and a live bench below. The probe listens for 24 hours; its report is deleted 7 days after that.
Live bench
Not listening- Requests
- 0
- From machines
- 0
- Opens, no request
- 0
- Fetched by a browser or inbox
- Fetched by a machine
- You opened it, request arrived
- You opened it, no request
- You opened it, unclear
- Copy under 15 min old
- 15 min or older
No probe yet. Create one, put it in a test email, and open it. Requests show up here within about three seconds.
Last verified by DynaMail
DynaMail runs the probe on its own test accounts and dates each result here. A result older than 90 days counts as unverified, because inboxes change without notice.
Gmail
Not yet verified by DynaMail. Your run is the evidence.
Apple Mail
Not yet verified by DynaMail. Your run is the evidence.
Outlook
Not yet verified by DynaMail. Your run is the evidence.
Yahoo Mail
Not yet verified by DynaMail. Your run is the evidence.
What a probe can’t see
- An open that shows a saved copy, or has images blocked, sends no request. It only counts if you press “I just opened it in…”.
- Proxies fetch on the reader’s behalf. The agent belongs to Google, Apple or Yahoo, not the reader.
- Inbox names come from user-agent patterns. Apple’s privacy proxy is inferred, so treat that lane as likely, not certain.
- Inboxes don’t publish how long they cache images, and it changes. A report is a snapshot of one run.
Privacy
- The probe stores no IP addresses and no locations. A report shows the fetcher type, a shortened agent string and times.
- A probe listens for 24 hours. Its report is deleted 7 days after that.
- Report links are unguessable and kept out of search engines. Anyone with the link can read the report; only your bench can add opens.
Frequently asked questions
What does Inbox Lens test?
Whether a live email image, like a countdown timer, is fetched again when a reader reopens the email, or shown from a saved copy. The probe image prints the time it was drawn, and the bench logs every request for it.
Does a live image update every time the email is opened?
No. It updates when the image is fetched. Some inboxes fetch through a proxy and reuse that copy for a while, and Apple’s privacy proxy can fetch it before anyone opens the email. Inbox Lens shows what happened in your run.
Why do I have to press “I just opened it in…”?
An open that shows a saved copy sends no request, so the probe can’t hear it. Your press marks the open, and an open with no request nearby shows up as a cached copy.
Do I need an account?
No. Create a probe, paste its image snippet into a test email, and open the bench on this page. The probe listens for 24 hours.
What data does a probe keep?
For each request: when it arrived, the kind of fetcher, a shortened user-agent string, and whether it asked for a fresh copy. No IP addresses and no locations. Reports are deleted 7 days after the probe stops listening.
Can I send the probe to my subscribers?
Use it only in test emails to your own inboxes. The report counts requests, not people, and anyone with its link can read it.
Live images by DynaMail. Countdowns, progress bars and live numbers that render when the email is opened.
See what DynaMail makes