When it comes to deliverability, many people immediately think of the big B2C players like Gmail, Outlook.com or Yahoo. But in B2B, the reality is very different.
Professional messaging systems are characterized by :
- A diversity of infrastructures Microsoft 365, Google Workspace, on-premise Exchange servers, local solutions...
- A multiple filters safety gateways, company-specific rules.
- A low error tolerance A technical detail can be enough to block your shipments.
The objectives of B2B emails vary: commercial relations, prospecting, internal communication, exchanges with partners... Recipients use professional messaging systems that are often custom-configured.
As a result, the filtering rules are not those of Gmail or Outlook.com. They are often stricter, and can change from company to company.
The aim of this article is to give you the keys to understanding this context, audit your deliverability and optimize your B2B campaigns.
Key differences between B2B and B2C deliverability
If the end goal is still the same, go to inboxThe rules of the game change radically between B2C and B2B deliverability.
In B2CIn addition, messaging services collect data from millions (or hundreds of millions for the biggest) of users. This enables them to develop reputation scores and filtering rules based on huge volumes of data.
Many companies, many different configurations
B2B deliverabilitythe entities you are addressing are smaller and more numerous. These range from very small companies with a few dozen employees to large structures with several thousand.
And even though Microsoft 365 (formerly Office 365) and Google Workspace are ultra-dominant in corporate messaging (see below), every system administrator on the occasion of personalize the aggressiveness of anti-spam filters used by the company. This results in a multitude of different configurations, the data used for filtering is more restricted, with policies specific to each company and often a high priority given to IT security.
Less data, more sensitivity
When Gmail (on the B2C side) receives a spam campaign, there's a good chance that it will receive several thousand messages. That's a lot of data to analyze, in terms of content, sending techniques and recipient reactions.
When a company receives a spam campaign, chances are it will receive 3 or 4 emails from that campaign (at best a hundred if the company is large or the campaign is very poorly targeted). That makes very few messages and very few recipient reactions to analyze before making a decision.
B2B spam filters will therefore be much more sensitive in deciding whether an email is spam or not. In low-volume environments, some complaints or an abuse signal sent to IT can lead to a block (manual rule or hardening). It's not systematicbut the risk is real
The specifics of B2B deliverability
Here are the main lines that create the specificities of B2B deliverability :
- Specific blocking lists In B2B, certain professional blocklists carry a great deal of weight in certain organizations. So keep a close eye on them.
- IP & domain reputation fluctuating very rapidly Reputation in B2B is harder to analyze (because information is not shared) and often more volatile. All it takes is a few spam complaints for your messages to stop arriving altogether.
- Safety-oriented filters Security: corporate e-mail administrators have important security objectives, so as not to infect their networks. Filtering for security reasons will therefore be very aggressive (analysis of attachments, links pointing outside the organization...).
- More frequent false positives A false positive is when an anti-spam filter mistakes a legitimate e-mail for spam. In this respect, spam filters used in a B2B context will be less reliable because they are more aggressive (sensitive) and less "intelligent" (using less data, especially behavioral data).
- A more closed environment Reputation is played out at the level of the target domain or company, not just the market as a whole. If you send the same email to two companies that both use Proofpoint and Microsoft 365, you could have totally different deliverability behaviors.
Categorizing B2B email types
To fully understand B2B deliverability, we need to understand the different types of email we send in B2B.
The more personal and desired the email, the easier it will be to deliver. Here is a hierarchy of the different types of email, from the easiest to deliver to the most complicated:
- Personal e-mails unit exchanges sent manually from the employee's e-mail inbox.
- Transactional e-mails : purchase confirmation, invoices, delivery tracking, service registration confirmation...
- Opt-in commercial emails newsletters, useful content, relevant offers.
- Unwanted opt-in commercial e-mails Recipient has registered but finds the content uninteresting (or has forgotten he/she had registered).
- Non-opt-in commercial e-mails : prospecting campaigns, cold emails, automated sequences.
- Spam, scams, phishing A proven reputational nuisance, often filtered right from the gateway.
Each category triggers different filtering behaviors: a transactional email will rarely be blocked, while an unsolicited cold email may be stopped before it even reaches the inbox.
💡Focus on cold email
Very popular, cold email imitates a personal message to approach an unknown prospect. But this apparent simplicity hides a high deliverability risk : lack of consent, likely spam complaints, attempts to bypass filters...
In the long run, these practices damage the domain's reputation and can block more than just your prospecting campaigns (even if you think you've applied all the "best practices" to hide yourself).
The diversity of B2B messaging services
But where will your B2B emails end up? In B2B, the diversity of technical environments is enormous: from Microsoft 365 ultra-dominant to internally hosted Exchange servers, including Google Workspace or other local solutions.
In addition safety walkways which filter before the messaging solution and apply their own rules.
And let's not forget that the professional world is not just about large companies or SMEs. If you sell to craftsmen or retailersYou could also have databases filled with addresses for the general public (Hotmail, Gmail, Orange...), which will then behave in a deliverable way. very close to B2C deliverability.
Two dominant messaging platforms
Two players dominate the professional email market:
- Microsoft 365 (61.4 % market share worldwide according to Validity).
- Google Workspace (35.4 % market share worldwide according to Validity).
Other secondary players exist (OVH, Amazon Workmail, Zoho, Gandi...), often more present among SMEs.
A wide range of filtering solutions
Security gateways play a major role:
- Proofpoint (50.4 % market share according to Validity)
- Mimecast (21.1 %)
- Cisco (12.1 %)
- Barracuda (10 %)
These filters often operate upstream (e.g. Proofpoint in front of Microsoft 365), apply customized anti-spam rules and can lengthen delivery times or generate temporary rejections.
So make sure you know who you're talking to!
When you have in front of you email addresses in @gmail.com or @laposte.netIt's easy to understand who you're talking to. This is not at all the case when the addresses are @ikea.com or @greenpeace.com . But it's still possible to find out which messaging systems or spam filters are hiding behind a corporate domain name.
Example: MX from @axa.fr points to mxa-00181c02.gslb.pphosted.com ? Proofpoint is the first-line filter, but we don't know which messaging service is used.
Method to find out the first-line filter:
- Use a tool like MxToolbox to identify MX server.
- Deduce the associated filter (Microsoft, Google, Proofpoint, etc.).
- Adapt your diagnostics and actions accordingly.
You can analyze your email database to extract the filtering tools used by your recipients. Do not hesitate to contact us if you wish to perform this analysis.
Need help?
Reading content isn't everything. The best way is to talk to us.
To find out more about the market share of B2B messaging and filtering solutions, read Validity's benchmark entitled Email Deliverability Benchmark Report.
Technical and operational constraints specific to B2B deliverability
Sending a B2B email isn't just a matter of getting past spam filters: you also have to get past a series of technical barriers designed to protect corporate information systems.
These constraints, often invisible to the sender, range from impeccable authentication requirements to strict security rules on attachments or links.
They require rigorous technical preparation and a thorough understanding of corporate safety practices.
Email authentication
As in B2C, theemail authentication has become crucial. It is no longer possible without SPF, DKIM or DMARC The alignment is more and more demanding, and failure to do so can block the email.
But be careful, if configure SPFDKIM and DMARC will be essential if you don't want your e-mails to be blocked by certain filters. Just because you've set them up doesn't mean your e-mails will be delivered.
Safety-oriented filters
In the corporate world, it's vital to protect against all digital threats. This ranges from protection against viruses and data theft to intrusion into the company's IT system. For these reasons, the B2B spam filtering isn't just a question of relevanceIt's also a question of safety.
For example, here are a few security rules that can have an impact on the delivery of your emails:
- Risky links blacklisted URLs, link shorteners (bit.lytinyurl), domains with no trust history.
- Prohibited attachments executable files (.exe, .bat), archives (.zip, .rar) or certain non-secure office formats (.xlsm).
- Suspicious content typical phishing or spam language, malformed HTML code, embedded scripts.
- Images hosted on an untrusted domain or hosted on a different domain from the sender.
- Misleading or overly generic object e.g. "Re:" or "Fwd:" used without prior exchange, considered a phishing attempt.
- Sending from a shared hosting network known to harbor spammers (e.g. certain AWS blocks, OVH...)
- ... and many more.
Reputation issues in B2B deliverability
As we have seen, in B2B, reputation isn't built on millions of emails sent, but often in much smaller volumes.
This low volume makes each incident more visible and more fraught with consequences: a few complaints or erroneous addresses can be enough to shut down access to an entire company.
B2B reputation management therefore requires precise monitoring, a gradual build-up and constant vigilance with regard to technical and relational signals:
- Low volume, high impact A single incident can severely damage your reputation.
- Snowball effect A few spam complaints can block your mailings for an entire company.
- Importance of progressive ramp-up and the construction of a solid relational track record.
Verification of blocking and IP/domain reputation
In B2B, blocking can target the sending IP address as well as the domain used in the From, links or image hosting.
As the two are closely linked in the confidence assessment of gateways, it is essential to monitor them jointly to detect and remove blockages quickly.
Key points to check :
- IP control tools Proofpoint, Cisco Talos, Barracuda, Trendmicro...
- Domain control tools Cisco Talos, Barracuda, Trendmicro...
- Priority analysis of bounces The best source of information to understand the exact cause of the blockage.
- Always cross-check public tool results with error messages received.
- Set up regular monitoring to prevent reputation deterioration.
💡The problem of ghost openings and clicks
In B2B, many security gateways automatically open emails and click on links to analyze possible threats. These opening and clicking actions are automated by robots, not by recipients.
As a result, your open and click rates can be artificially inflated, making performance analysis misleading. It's more complicated (as we do in B2C) to track deliverability by comparing click and open rates by destination.
Even if this has no direct impact on deliverability, it can distort marketing decisions.
See our article on detection of robot clicks and opens in emails.
B2B data collection and legal compliance
In B2B, the legislation on consent is often more flexible than in B2C, but this flexibility should not be confused with total freedom, still less with the requirements of anti-spam filters. In fact, this greater flexibility often justifies very aggressive practices, which are heavily penalized in terms of deliverability.
In most European countries, including France, it is possible to send prospecting emails. without prior opt-in if :
- The email address is generic (info@, contact@...).
- The content of the email is directly related to the professional activity of the person or company.
- The recipient has been informed of the possibility of objecting to the receipt of commercial emails.
Even if opt-in is not always required, the relevance and transparency remain your best allies in maintaining good deliverability. An aggressive or untargeted approach quickly degrades the trust of filters and recipients, with often lasting impacts on your reputation and email delivery (see our box on cold emailing).
Best practices for optimizing B2B deliverability
In B2B, the success of a campaign depends not only on good content: it also depends on your ability to overcome a demanding technical environment and establish a relationship of trust with each company contacted.
Good practices are therefore as much techniques that relationaland must be applied on an ongoing basis, not just during a one-off audit.
Here is a 15-point checklist to maximize your chances of reaching the B2B inbox:
- Check SPF/DKIM/DMARC Check that your domains are properly authenticated on a regular basis.
- Analyze your recent bounces Isolate domains that are sending rejects, read messages and bounces and adjust sending (e.g. reduce volume or correct configuration).
- Scan your links : Test the domains you use (sending, linking, image hosting) in tools such as Sucuri or URLVoid to avoid a blockage.
- Host your images on a reliable domain Avoid free or little-known CDNs, or hosting images on your e-mail router's infrastructure if you can't customize the domain name. Prefer a corporate sub-domain in HTTPS.
- **Clean up the inactive**: Remove old B2B addresses for which you can't prove any recent activity (sales contact, orders, customer login...).
- Avoid shortcut links : Replace the bit.ly/tinyurl with your full URLs. If you really need to share short links, prefer a customizable url shortener with a home-grown domain.
- Check your attachments Limit the number of attachments you send. If you really must, send only PDFs or secure formats.
- Adapt the subject to the recipient Avoid misleading objects ("Re:", "Fwd:" without exchange) or overly generic ones.
- Personalize the sender Use an identifiable name and address (e.g. prénom.nom@entreprise.com) that the recipient can trust and that is legitimate.
- Detecting false clicks Identify robot opens/clicks and filter them in your analyses. Don't hesitate to ask your e-mail solution what is in place at this level.
- Insert a clear unsubscribe link Make it easy to unsubscribe from your mailings! You'll probably avoid spam complaints, which can be very damaging to your reputation.
- Preparing a warming scenario On a new domain or a new IP, when changing your email tool, prepare your warmup carefully.
- Check Outlook compatibility : Display an email correctly on Outlook is not always easy, but this email client is still dominant in B2B. An email that looks good is more likely to be read and appreciated by your recipient 😉
- Monitor your reputation With Talos, Barracuda Central, Proofpoint, and act quickly if a blockage occurs.
- Put yourself in the recipients' shoes Okay, you're going to generate sales with your campaign. But would you like to receive this email? Would it be relevant or irritating?
💡Resolving a B2B deliverability incident
A deliverability incident in B2B is not the same as in B2C. Messaging systems are often customized by each company's system administrators. Even if two recipients use Microsoft 365 and Proofpoint, their filtering rules may be radically different. The causes of blocking are therefore not always reproducible and vary from one organization to another.
Diagnosis begins with theSMTP bounce analysiswhich remain the most reliable source of information. By isolating incidents by domain, it is possible to determine whether they are limited to a single environment or more widespread. Once the cause has been identified, it may be necessary to adapt content, links or image hosting to meet local requirements.
Access to the right technical contacts is often difficult: you have to go through the customer's sales or marketing contact to reach the IT administrator, which lengthens lead times and sometimes dilutes the technical message. In this context, patience and precision in communication are essential.
Finally, resumption of mailings should be gradual. Testing on a small group of addresses before relaunching on a large scale validates that the modification applied has indeed lifted the blockage. In B2B, every resolution is tailor-made: what works for one company will not necessarily be effective for another.
Conclusion: B2B deliverability, a balance between technique and relevance
B2B deliverability is not a minor variation on B2C deliverability: it's a playground of its own, where each company contacted applies its own rules, and where tolerance for error is minimal.
In this environment, a technical detail, a poorly targeted mailing or an overly aggressive approach can be enough to block access to an entire organization.
Success means combining three levers:
- An impeccable infrastructurewith aligned authentication, reliable hosting and careful configuration.
- Consistent database hygieneto contact only relevant and up-to-date addresses.
- A targeted relational approachwhich favors relevance and transparency over quantity.
The key is to treat each mailing as a unique interaction with a closed ecosystem, not as an undifferentiated mass mailing. Don't hesitate to train you in deliverability to become self-sufficient in these matters.
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