Customer.ioOpen-tracking pixel, click tracking and unsubscribe
Customer.io can insert an open-tracking pixel, and lets you remove it campaign by campaign as well as contact by contact.
Enterprise · Peaberry Software · vendor's site ↗ · code customer-io
Messaging automation platform founded in 2012 that sends emails, push notifications, in-app messages and SMS based on the brand's own data.
Postmetry reference sheet
What the vendor says, checked by us
4 sources · last reviewed on 08/18/2026. Still not checked: Tracking anonymization, List-Unsubscribe, RFC 8058 — one click, Preferences page, Transactional exceptions, DKIM, SPF, DMARC, Sending domain, Tracking domain, Logging, API, Consent history, Granularity of settings.
Postmetry corpus
What brands actually send
9 messages received from 10/07/2026 to 10/30/2026. Below the threshold of 30 messages and 8 brands: no rate is published.
Postmetry reference sheet
What this ESP allows
Catalog shared by both pages. Each note carries its source, its date, and its confidence level.
On the right, what our emails say about it: matching, contradicted, never observed despite the volume, too few emails to conclude — or out of reach, when the capability can't be read from an email.
Tracking 2 not verified
Open pixel Yes 1 note · 18/08/2026 Too few emails seen on 7 of 7 emails from 1 brand, 1 months
Open tracking relies on a "tracking pixel" in your messages
Caveat Pixel by default, and can be disabled globally at workspace level since August 2021 — the vendor itself justifies the setting by privacy and the declining reliability of the metric. Rare: a dated release note.
Disable open tracking · Help centre · last reviewed on 08/18/2026 · confidence medium
Click tracking Yes 1 note · 18/08/2026 Too few emails out of 7 emails from 1 brand, 1 months
just add the untracked class to the button, image, or text link
Caveat Tracking by default, opt-out per link via the untracked class (drag-and-drop editor) — justified by click-rate accuracy. Tracked links are served over HTTPS; the vendor advises against tracking sensitive links (password resets).
Disable link tracking in the drag-and-drop editor · Help centre · last reviewed on 08/18/2026 · confidence medium
Exclusion by campaign Yes 1 note · 04/08/2026 Out of reach
uncheck Track opens and link clicks in this message on the left
Caveat A switch per message (email: opens and clicks; SMS/WhatsApp: clicks). For an entire automation, email must be disabled one email at a time.
Link Tracking · Help centre · last reviewed on 08/18/2026 · confidence medium
Consent — absence means no pixel Yes 1 note · 04/08/2026 Out of reach
The only one in the batch to do exactly what the recommendation describes. Three modes — disabled, opt-in, opt-out — a reserved attribute `cio_email_tracking_consent` with the states `granted` and `denied`, and a hosted page where the recipient can change their mind. In opt-in mode, a contact without consent does receive the message, without a pixel: the email goes out, the measurement does not. This is the distinction the other tools cannot make.
Observations in the interface, first batch · Interface · last reviewed on 08/04/2026 · confidence medium
Unsubscribe 4 not verified
Authentication 5 not verified
Infrastructure & governance 4 not verified
Postmetry corpus
Observed in our corpus
Recorded by our analyzers on messages received on addresses we control. Nothing from the reference sheet here, no access to the tool.
9 messages, 1 brand, below the threshold of 30 messages and 8 brands: no rate is published. A percentage on so few emails, or so few brands, describes what one brand configured, not what the sending platform does.
Period observed
10/2026 → 30/10/2026
1 months, 1 distinct brand.
Identification signals
What we recognized the sending platform by, message by message.
- X-Mailer 100 %
Limits of this analysis
It doesn't say what a brand has actually configured. A sending platform that allows turning off the pixel says nothing about which brands have done so — that's what a brand's report answers.
It doesn't rank. No score, no recommendation: capabilities don't carry the same weight depending on the use, and that weight isn't ours to set.
A “not checked” cell is not a “no”. It says nobody has gone to look yet, and nothing else.
The corpus does not establish a capability. A rate of observed pixels says what brands send, not what the tool can do.
Sources
4 sources- Link Tracking Help centre · confidence medium 18/08/2026
- Disable open tracking Help centre · confidence medium 18/08/2026
- Disable link tracking in the drag-and-drop editor Help centre · confidence medium 18/08/2026
- Observations in the interface, first batch Interface · confidence medium 04/08/2026
Comparable sending platforms
Compare the whole family →Frequently asked questions
Can you turn off open tracking in Customer.io?
Does Customer.io rewrite links for click tracking?
Do your emails go through Customer.io?
The sending platform is read from the headers, not from a claim. The report names it, and says where to fix the findings with that vendor.