Deliverability: the checklist to nail your September email restart

September's back. Everyone's in the office, the calendar fills up again, Q4 targets land back on your desk, and you finally get five minutes to look at your email programme.

That's when it hits you. This one isn't like previous years.

• France's data protection authority published its recommendations on email tracking pixels in April. Open rate has lost its status as a steering metric, permanently.

• Google shut down the old version of Postmaster Tools. No more domain or IP reputation grades.

• You have 77 days until Black Friday, with fewer instruments than ever to plan with.

Getting back up to speed on deliverability after summer 2026 isn't comfortable. So we pulled together the priorities we're working through with customers right now.

1. Tracking pixels: is your CNIL compliance actually holding?

If you send to recipients in France, this one applies to you.

The deadline passed on 14 July 2026. The CNIL recommendation on email tracking pixels, published on 14 April, gave senders three months to inform contacts already in their database, without having to go back and ask for fresh explicit consent.

If that project got finished in a scramble in early July, three things are worth re-checking.

1. You collect consent on your account creation and newsletter sign-up forms.

2. Every email now carries a link to withdraw consent for tracking pixels.

3. Your data team stored proof that the information campaign went out before 14 July, through Batch's Profiles API.

Most importantly, check that you switched on the dashboard setting that tells Batch to insert a pixel only when consent exists.

"Conditional pixel insertion" setting in the Batch dashboard

2. Make spam complaints your steering metric

Adapt, or stop reaching the inbox

Your recipients hold all the power over their inbox now. Mailbox providers give more and more weight, rightly, to what their own users tell them.

Yet volume and list-growth targets, still baked into CRM habits, carry no weight with mailbox providers. They're purely internal metrics, with zero influence on those decisions.

For two years now, spam complaints have been able to undo a reputation built over years, and wipe out weeks of migration prep.

Google Postmaster Tools: the first issues you need to address

In short, your recipients decide whether you get to reach the inbox.

Which makes September the right moment to review your whole CRM programme through that lens. The downside case starts at missing your Black Friday sends, and ends at losing the ability to reach your base at all.

For reference, Google asks senders to stay below 0.3% spam complaints per day, and recommends aiming for 0.1%. Other providers say less about their thresholds, but work on comparable logic.

Spot the bias in your own targets

None of this is new. What changed is how central it became in the algorithms that set sender reputation.

Which means habits built around the sender, perfectly reasonable a few years ago, now chip away at your reputation and your medium-term performance every single day.

A few examples, with the alternatives we recommend in our deliverability workshops.

1. Grow the number of marketing subscribers

Try this instead: Rework the consent request. Make sure it's clear and explicit.

Why: Consent has to be freely given, specific, informed and unambiguous to be valid. Given what complaints cost your reputation, quality of subscription beats volume.

2. Bring unsubscribe volumes down

Try this instead: Make unsubscribing easy, and find out what's driving it.

Why: Unsubscribing is the last line of defence before a spam complaint. It should be as simple as subscribing was. A clumsy or technically broken unsubscribe is also a legal risk.

3. Increase send volume

Try this instead: Match frequency and volume to each audience. Make sure the message and the offer are worth something to the recipient.

Why: Turning up marketing pressure is one lever among several, and it usually crowds out the underused ones, like making the message better. It's also the riskiest, because it's the most likely to annoy people.

4. Extend reach during peak season by waking up dormant contacts

Try this instead: Personalise the offers you put in front of people. Pre-qualify dormant audiences before you even consider targeting them.

Why: Targeting inactives is the single most common Black Friday mistake. You wake up people who had forgotten you, you hit thousands of dead addresses, and above all you trigger every anti-spam protection there is.

How to review your sendings

Track your complaint rate in Google Postmaster Tools

The tool shows your daily spam complaint rate per sending subdomain. That's the reference source for judging how much risk your sender reputation is carrying.

Any spike above 0.3% should trigger an investigation.

High-risk example in Postmaster Tools, with repeated threshold breaches

When something goes wrong, Google lists the campaign IDs concentrating the most complaints.

Postmaster Tools screenshot listing the campaign IDs concentrating the most complaints

That's your cue to dig into that campaign and work out what set it off. The usual suspects:

• a targeting, content or scheduling mistake;

• a marketing email wrongly classified as essential, so shipped without an unsubscribe link;

• marketing pressure set too high;

• an unsubscribe link with a poor experience, or a technical fault such as an unsubscribe request that never gets honoured;

• an audience that's too broad and not specific enough.

On that last one, tagging acquisition source at profile level helps enormously. What a recipient wants depends heavily on what they signed up to. Someone who came through a prize draw expects something different from a newsletter subscriber, or from a customer who created an account.

Sometimes the original deal is what got broken. The person never understood they were signing up for marketing emails. That's a sign to go back and fix the sign-up journey itself.

Run a post-mortem

If no clear reason emerges, block out time to analyse the context around your complaints. Batch lets you export the complaint list, then trace back every action that led there.

Batch export of the complaint list and the associated actions

Use Email Quality Assistant

Email Quality Assistant is Batch's AI email diagnostic tool. It checks more than 30 points on each of your emails, from the components of your template through to content quality, and returns recommendations you can act on straight away.

Email Quality Assistant diagnostic preview

3. Build the right monitoring habits

On 30 September 2025, Google announced it was retiring the old Postmaster Tools interface. As of 20 August, it's finally done.

What's gone: domain and IP reputation grades, those four levels, bad, low, medium and high, that plenty of teams had been steering by for years.

What replaces them: a compliance dashboard that answers yes or no on SPF, DKIM, DMARC, forward and reverse DNS records, From header alignment, the share of traffic encrypted over TLS, one-click unsubscribe, and honouring unsubscribe requests within 48 hours.

The shift in method is real. You're no longer watching a slow-moving summary indicator. You're watching binary compliance and a daily complaint rate. Two practical consequences.

• You now catch an incident on the complaint rate, not on a reputation grade changing colour.

• Monitoring moves from weekly to daily through high-pressure commercial periods.

Set yourself up test addresses too, on Gmail and Outlook at minimum, then at whichever providers carry the most weight in your base. Send every test email there. It's the simplest way to check what actually happens to your mail at the providers that matter to you.

4. Prepping Black Friday and Christmas: the reverse plan

Black Friday falls on 27 November 2026. Sender reputation degrades in days and takes far longer to rebuild. So this peak gets prepared now.

Black Friday / Christmas reverse plan (clean-up, reactivation, volume ramp, structure freeze)

Until 30 September: the clean-up

Exclude long-term dormant contacts, clean out invalid addresses (gamil.com, yhoo.fr and friends), fix whatever non-compliance Postmaster Tools is flagging.

October: reactivation

This is your last window to try to win back inactives, on controlled volumes and tight segments. A contact reactivated in October is a contact you can use in November.

1 to 20 November: ramping volume

Step by step, most engaged segments first, with a daily read on complaint rate per recipient domain.

After 20 November: nothing structural moves

No new sending domain, no new IP, no authentication changes. You execute.

One last thing

Deliverability isn't a fire you put out after the fact anymore. It's capital, built up or eroded week by week, under your recipients' watch. Mailbox providers just carry out their verdict.

There are 77 days left to rebuild that capital properly. Wait until the week before Black Friday, and there won't be time left for anything.

No CRM team pulls off a shift like this on its own. That's why we run these deliverability workshops all year round: pooling what works, so nobody has to relearn the same lessons the hard way. If this September is the right moment to get started, come talk to our teams.