What is a good spam complaint rate?

Keep it under 0.10%, and never let it reach 0.30%. Those are the thresholds Google and Yahoo apply to senders. Microsoft publishes no number, so use the same targets. Complaint rate is the share of delivered messages that recipients mark as spam. Google Postmaster Tools shows it for Gmail. Pause a campaign when you approach 0.10%, then find the list or message that caused it before you send again.

Do I need SPF, DKIM and DMARC for cold email?

Yes. Gmail, Yahoo and Microsoft expect all three, and they reject or filter mail that fails them. Set them up on every domain you send from. You can start DMARC at p=none to collect reports, then tighten it. Authentication does not guarantee the inbox, but without it you will not get there.

Can I send cold email from my main company domain?

We advise against it. Use separate, related domains for cold outreach so that a reputation problem does not reach your normal business email. Warm each new domain gradually, authenticate it, and keep volumes modest per mailbox. Reserve the main domain for customers, transactional mail and opted-in marketing.

How long does email warmup take?

Plan for six to eight weeks for a new domain. A damaged domain needs at least three weeks of careful ramping, and some are better retired. Start with a handful of emails a day and increase week by week while bounces and complaints stay low. The schedule is a rule of thumb, not a provider limit, so adjust it to what your own data shows.

Is cold email legal for B2B?

In many countries it is, with conditions. In the US, CAN-SPAM requires an honest message, a physical address and a working opt-out. The EU, the UK and Canada add consent or legitimate-interest rules. Rules differ by country and change over time. This is general information, not legal advice. Take advice for the markets you target, and honour opt-outs quickly everywhere.

Our emails already go to spam. What should we do first?

Pause sending, check authentication and blocklists, and cut the list to engaged, verified contacts. Then restart at low volume. Look at Google Postmaster Tools and your bounce and complaint rates to find the cause. If a domain stays damaged, retire it and warm a new one. We cover the steps in the recovery plan above.

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Guide

How to run email campaigns that reach the inbox, not the spam folder

Email lands in spam for three reasons: the sender cannot be verified, recipients do not want the message, or the sending pattern looks like a spammer. Fix authentication, list quality, volume and content, then watch complaints and keep them under 0.1%.

By Search Value · Updated 21 October 2026

Why it happens
The 2026 rules
Authentication
Domains and warmup
Lists
Content
Monitoring
The law
Recovery

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Authentication and warmup steps
List hygiene and content rules
Weekly monitoring thresholds

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Why it happens

Why campaign emails end up in spam.

Mailbox providers cannot verify you

Without SPF, DKIM and DMARC, a message looks the same as a forgery. Gmail, Yahoo and Microsoft now reject or filter mail that fails these checks.

Recipients do not want the email

People mark mail as spam, or ignore it, when it is irrelevant, unexpected or hard to unsubscribe from. Complaints and low engagement damage your reputation faster than anything else.

Your sending pattern looks wrong

A new domain that sends thousands of emails on day one, a list full of dead addresses, or sudden volume jumps all look like spam, whatever the content says.

Reputation follows your domain and IP

Providers score the domain and the sending address over time. A few bad campaigns can hurt every email you send after, including mail from your own team.

The rules

What Gmail, Yahoo and Microsoft expect in 2026.

Google and Yahoo began enforcing sender rules in 2024, and Microsoft followed for Outlook.com, Hotmail and Live addresses in May 2025. The formal rules apply to bulk senders, usually defined as 5,000 or more messages a day to their users. In practice, treat them as the standard for every campaign, because the filters look at the same signals whatever your volume.

Requirement	What it means
SPF and DKIM	Both must pass, and at least one must align with the domain in your From address.
DMARC	A published record is required, at least `p=none`. Moving to `quarantine` or `reject` is the better long-term position.
One-click unsubscribe	Promotional mail needs a one-click unsubscribe header (RFC 8058) as well as a visible link. Honour requests within two days.
Complaint rate	Keep spam complaints below 0.10% in Google Postmaster Tools. At 0.30% you risk blocks and lose access to some mitigation. Microsoft publishes no number, so use the same targets.
Valid sending setup	Reverse DNS that matches your sending host, TLS in transit, and correctly formatted messages.

Enforcement has tightened. Google moved from temporary deferrals to permanent rejections of non-compliant mail in late 2025, and Microsoft rejects it outright. Thresholds and dates are reported slightly differently by different sources, so check the current Google, Yahoo and Microsoft sender documentation before you rely on a specific figure.

Step 1: Authentication

Prove that the email is really from you.

SPF lists the servers allowed to send for your domain. DKIM adds a signature to each message that the receiver checks against a public key in your DNS. DMARC tells receivers what to do when SPF or DKIM fails, and sends you reports.

Set up all three for every domain and subdomain you send from, including your email platform and any CRM or sales tool that sends on your behalf. A simple DMARC record to start with looks like this:

v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

Read the reports for a few weeks, fix any legitimate sender that fails, then tighten the policy to quarantine and later reject. Check the result with a tool such as Google Admin Toolbox, or send a test message to a mailbox and read the authentication results in the message headers.

Step 2: Domains and warmup

Protect your main domain and ramp up slowly.

Do not send cold outreach from your main domain. Use separate, closely related domains or subdomains for outbound prospecting, and keep your main domain for customer, transactional and opted-in mail. If a cold campaign damages a sending domain, your regular business email is not affected.

A new domain or mailbox has no reputation. Providers expect it to start small and grow. A typical schedule for a new sending domain, from vendor guidance, looks like this:

Week	Emails a day, per mailbox	Notes
1	5 to 10	Send to engaged contacts and colleagues. Replies help.
2	15 to 25	Keep the same daily pattern.
3	30 to 50	Start real, well-targeted prospects.
4	60 to 90	Watch bounces and complaints daily.
5	100 to 140	Do not add new content and volume together.
6 to 8	150 to 200	Plateau. Add more domains and mailboxes for more volume, not a higher ceiling.

These figures are a conservative rule of thumb, not a provider limit. Allow six to eight weeks for a brand new domain and at least three weeks to recover a damaged one. Add domains rather than pushing one domain harder.

Step 3: Lists

Send only to addresses that are real and relevant.

Never buy or scrape a list. Purchased lists contain dead addresses, spam traps and people who never heard of you. One send can undo months of work.
Verify addresses before the first send. Remove invalid, role-based and risky addresses. Vendors treat a bounce rate near 5% as critical, so aim to stay far below it.
Collect permission where you can. For opted-in mail, use a clear sign-up and record where and when each person agreed. Double opt-in gives the cleanest list.
Segment by role, industry and stage. Relevant mail gets opened and replied to. Mass mail gets reported.
Retire inactive contacts. Stop mailing people who have not opened or clicked in about six months, or move them to a re-permission email. Inactive addresses drag down your engagement.
Make leaving easy. A visible unsubscribe link and the one-click header cost you a few contacts and save your reputation.

Step 4: Content and sending

Write like a person and send like one.

Be recognisable

Use a real name and a consistent From address on a domain you own. Make the subject line match what is inside.

Keep it plain

One clear message, one link, little formatting. Avoid image-only emails, URL shorteners, attachments in cold mail and anything that looks like a mass mailer.

Match the offer to the reader

A guide or a short review for a named role in a named industry performs better than a generic pitch. Relevance is the best spam filter you have.

Keep a steady rhythm

Send at a consistent volume and cadence. Spread large sends over hours or days, and stop a sequence when someone replies or bounces.

Say who you are

Include your company name and a physical address, which US law requires, and a clear reason for writing.

Test before you send

Send to your own seed addresses at Gmail, Outlook and Yahoo, and read the result in the spam folder and the message headers.

Step 5: Monitoring

Watch the numbers and stop early.

Reputation problems are cheap to fix in week one and expensive in month three, so look at the signals every week.

Signal	Where to see it	Act when
Spam complaint rate	Google Postmaster Tools, your email platform, feedback loops	It approaches 0.10%. Pause the campaign and review the list.
Hard bounce rate	Your email platform	It rises above your normal level. Stop and verify the list.
Domain and IP reputation	Google Postmaster Tools, Microsoft SNDS	Reputation drops from high to medium or low.
Inbox placement	Seed-address tests	Mail moves to spam at any one provider.
Blocklists	Public blocklist lookup tools	Your domain or IP is listed.
Replies and opt-outs	Your inbox and email platform	Opt-outs climb, or replies turn negative.

Judge campaigns by replies, sales-accepted leads and the lead-to-SAL ratio, not by opens. Open rates are distorted by privacy features such as Apple Mail Privacy Protection.

The law

Cold email and opted-in email follow different rules.

	Cold B2B outreach	Opted-in newsletters and nurture
Basis for sending	US: no prior consent needed, but all CAN-SPAM rules apply. EU and UK: usually legitimate interest, with a documented assessment. Canada: express or implied consent.	Consent recorded at sign-up. Keep the date, source and wording.
Every message	Accurate From and subject line, your identity, a valid physical address, and a working opt-out.	The same, plus content that matches what people signed up for.
Opt-outs	Honour them promptly. CAN-SPAM allows 10 business days, and providers expect two days.	Process them within two days and suppress the address permanently.
Penalties	CAN-SPAM fines run to tens of thousands of dollars per email. GDPR fines reach 4% of global turnover. CASL fines reach CAD 10 million per violation.	Same laws apply.

India's Digital Personal Data Protection Act also covers how you collect and use personal data, so check it if you email contacts in India. This guide is general information, not legal advice. Take advice for the countries you target.

Recovery

Already in spam? A 30-day recovery plan.

Week 1

Stop and diagnose

Pause campaigns. Check SPF, DKIM and DMARC, blocklists, Postmaster Tools and your bounce and complaint rates. Find which list or campaign caused it.

Weeks 2 and 3

Clean and rebuild

Cut the list to engaged and verified contacts. Remove everyone who bounced or complained. Restart at a fraction of your old volume, to your most engaged people first.

Week 4 onward

Grow carefully

Increase volume a little at a time while complaints stay low. If a domain stays damaged, retire it and warm a new one. Do not use your main domain as the fix.

Checklist

Before every campaign.

SPF, DKIM and DMARC pass on every domain you send from.
Cold outreach is not on your main domain.
The list is verified, and nobody inactive is on it.
Unsubscribe works, visible link and one-click header.
Volume is ramped, not jumped.
Postmaster Tools and bounce reports are checked weekly.
Complaints are under 0.10%. If not, pause.

How we run nurture programmes →

Free checklist

Take the checklist to your team.

A printable pre-send checklist: authentication, domains and warmup, lists, content, monitoring and the law.

Authentication and warmup steps
List hygiene and content rules
Weekly monitoring thresholds

Your checklist is ready.

Save it, print it, or send it to your team.

Download the PDF

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How to run email campaigns that reach the inbox, not the spam folder

Take the checklist to your team.

Your checklist is ready.

Why campaign emails end up in spam.

Mailbox providers cannot verify you

Recipients do not want the email

Your sending pattern looks wrong

Reputation follows your domain and IP

What Gmail, Yahoo and Microsoft expect in 2026.

Prove that the email is really from you.

Protect your main domain and ramp up slowly.

Send only to addresses that are real and relevant.

Write like a person and send like one.

Be recognisable

Keep it plain

Match the offer to the reader

Keep a steady rhythm

Say who you are

Test before you send

Watch the numbers and stop early.

Cold email and opted-in email follow different rules.

Already in spam? A 30-day recovery plan.

Stop and diagnose

Clean and rebuild

Grow carefully

Before every campaign.

Take the checklist to your team.

Your checklist is ready.

Send us your current email setup.

Email deliverability: questions, answered.

Related guides and services.

Lead-to-SAL ratio

B2B digital marketing plan

Inbound and lead nurturing

EXL Service case study

Find out where your email programme leaks.

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