Cold Email Deliverability Checklist 2026 (with Amplemarket)

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Your cold emails can be well written, well targeted and still never get read. If they land in spam, nobody tells you. They just stop getting replies.

This checklist covers cold email deliverability in 2026 from the domain you buy to the dashboards you check each week, in eleven numbered steps. It is based on the vendors’ own docs and public pages (Amplemarket and SMTP2GO), plus Google’s and Yahoo’s published sender requirements, with pricing as of November 2026. Where the docs do not cover something, or disagree with each other, we say so.

The cold email deliverability checklist at a glance

The first four are one-time setup. The rest are habits.

#	Step	Done when
1	Separate sending domain	Cold mail no longer goes out from your main domain
2	SPF	One valid SPF record covers your mail provider
3	DKIM	Mail is signed, ideally with a 2048-bit key
4	DMARC	A record exists with at least p=none, and DMARC passes
5	Google and Yahoo rules	You meet the all-sender rules and plan for the bulk rules
6	Warmup	Each new mailbox has followed a gradual ramp
7	Volume limits	A daily cap is set per mailbox, with no spikes
8	List hygiene	Addresses are validated and bounces are removed automatically
9	Content	Plain, honest, few links, no hidden content
10	Unsubscribe	Every email has an opt-out, honored fast
11	Monitoring	Someone checks spam rate and placement every week

Read this first: Gmail and Yahoo do not endorse cold email

The official guidance from both mailbox providers is written for mail people asked for.

• Google says: “Make sure recipients opt in to get messages from you” and “Don’t purchase email addresses from other companies.”
• Yahoo says: “Verify you’re only sending mail to users who specifically requested it,” and advises against buying lists.

Everything below reduces your risk. None of it makes unsolicited mail something Google or Yahoo approve of. Recipients who hit “report spam” directly raise the number both providers watch.

Cold email is also regulated. The FTC says CAN-SPAM “makes no exception for business-to-business email.” Rules differ by country, and this post is not legal advice.

Step 1: Use a separate sending domain

If cold outreach damages a domain’s reputation, you do not want that to be the domain your invoices and customer replies come from. Amplemarket’s deliverability guide describes two forms: a subdomain (mail.company.com) and a secondary domain (companyemail.com instead of company.com).

This recommendation comes from Amplemarket and common outbound practice. Google’s and Yahoo’s pages do not tell you to do it. Two things to know:

• A subdomain does not reset Gmail’s count. Google’s FAQ says messages from the same primary domain count toward the 5,000 limit, with subdomains added together.
• A separate domain is not a loophole. It limits the damage. It does not excuse unwanted mail, and the new domain still has to follow every rule below.

How to set it up

1. Buy a domain close to your brand, one that a recipient would recognize as yours.
2. Point its website address at your main site, so anyone who checks it finds a real company.
3. Create 2 to 3 real mailboxes per rep. Amplemarket’s older how-to suggests “around 2 to 3 accounts per sales rep.”
4. Fill in names and profile photos.
5. Do not hide your primary address behind an alias on the new domain. Amplemarket’s guide warns against masking it.

Amplemarket’s guide mentions 5 to 10 domains only for teams reaching 200,000 or more people a month. A small team should start with one. Google’s FAQ also mentions a faster enforcement timetable for new domains, so authenticate before you send anything.

Step 2: Publish one SPF record

SPF lists the servers allowed to send mail for your domain. It is a DNS TXT record on your new domain.

• For Google Workspace, Amplemarket’s setup guide gives v=spf1 include:_spf.google.com ~all with host @.
• Have only one SPF record per domain. If one exists, add the new include to it instead of creating a second.
• Follow a provider-specific guide. Amplemarket publishes them for Google Workspace and Microsoft 365, including versions for specific DNS hosts.

Step 3: Turn on DKIM

DKIM adds a signature that lets the receiving server confirm the message was authorized and not altered. You generate the record in your mail provider’s admin panel, add it to DNS, then start authentication.

• In Google Workspace, this happens on the DKIM Authentication page in the Admin console. Amplemarket’s guide notes it can take minutes to hours for Google to recognize the record.
• Key length: Google requires at least 1024 bits and recommends 2048. Yahoo also sets a 1024-bit minimum.

Step 4: Publish DMARC, then read the reports

DMARC ties SPF and DKIM to the address people see in the From line and tells receivers what to do with failures.

1. Add a TXT record with host _dmarc. Amplemarket’s guide gives v=DMARC1; p=none; as the starting value.
2. Add a reporting address with a rua tag. Yahoo strongly recommends this for monitoring during setup.
3. Check alignment. Both providers require the From domain to align with the SPF or DKIM domain. Yahoo accepts relaxed alignment.
4. Keep only one DMARC record for the host.

Both providers accept p=none as the minimum. Yahoo adds that DMARC must pass, so a record alone is not enough. To test all three records, Amplemarket’s guide says to open the Domain Health Center, select a mailbox, click the Authentication cell and press “Run tests.” Without Amplemarket, it points to MXToolbox’s free SPF, DKIM and DMARC tools.

Step 5: Meet the Google and Yahoo sender rules

These figures come from Google’s email sender guidelines, Google’s FAQ, Yahoo’s Sender Best Practices and Yahoo’s FAQ, as published when we checked in November 2026.

Requirement	Gmail	Yahoo
All senders: authentication	SPF or DKIM	SPF or DKIM at a minimum
All senders: spam rate	Below 0.3%, with a target below 0.10%	Below 0.3%
All senders: DNS	Valid forward and reverse DNS (PTR)	Valid forward and reverse DNS
Who counts as bulk	Close to 5,000 or more messages to personal Gmail accounts in 24 hours	“A significant volume of mail,” with no number given
Bulk: authentication	SPF and DKIM, plus DMARC at p=none or stricter	SPF and DKIM, plus DMARC at p=none or stricter, and DMARC must pass
Bulk: From alignment	Aligned with SPF or DKIM domain	Aligned with SPF or DKIM domain
Bulk: unsubscribe	One-click for marketing and subscribed messages, plus a visible link in the body	List-Unsubscribe header with one-click for marketing and subscribed messages, plus a visible link
Bulk: honoring opt-outs	Within 48 hours, per the FAQ	Within 2 days

Three details that catch people out

• Gmail bulk status is permanent. Google’s FAQ says senders who meet the criteria once are “permanently considered bulk senders.” Google’s guidelines page words the threshold slightly differently (“more than 5,000”), so do not plan to sit just under it.
• Enforcement is active. Google says that starting November 2025 it is ramping up enforcement on non-compliant traffic. Yahoo says non-compliant mail may go to spam or be rejected.
• Spam rate is based on inbox mail. Yahoo says it calculates the rate from mail delivered to the inbox, and Google’s Spam Rate dashboard works on messages that landed in the inbox. So heavy spam-folder placement can hide a problem instead of showing one.

A small team sending a few hundred emails a day is unlikely to reach Gmail’s bulk threshold. Meet the bulk rules anyway, since most are DNS records you set once.

Step 6: Warm up every new mailbox

Warmup comes in two forms that are easy to confuse:

• Real volume ramp. This is what Google describes: “Start with a low sending volume to engaged users, and slowly increase the volume over time.”
• Warmup networks. A service exchanges emails between participating mailboxes to create activity. Google’s guidelines page does not mention these, and Yahoo’s page gives no ramp guidance at all.

You need the first in any case. Amplemarket’s own guide says its Deliverability Booster does not replace a gradual volume ramp. Its help article on email warmup describes a 12-week plan with this recommended number of net new leads per day, per mailbox:

Week	Net new leads per day (per mailbox)
Weeks 1 to 2	Up to 5
Weeks 3 to 4	5 to 10
Weeks 5 to 7	10 to 15
Weeks 8 to 10	15 to 20
Weeks 11 to 12	20 to 30
After week 12	Up to 30, increasing slowly

According to the same article, warmup runs on weekdays only and starts 2 to 4 new conversations each weekday with mailboxes in other Amplemarket accounts, never your own team. If a warmup email lands in spam, the service moves it out and marks it as read. It also warns that warmup can’t fix a Microsoft block: an admin has to unblock the mailbox first.

One inconsistency: other Amplemarket articles say to warm up “at least four weeks,” while the help article uses 12 weeks. We would follow the 12-week table.

Step 7: Set volume limits and keep them steady

No provider publishes a safe cold email number. Amplemarket’s July 2026 article says so too. Its pages give several figures, which do not fully match:

• Help article: up to 30 net new leads per mailbox per day after 12 weeks, increasing slowly.
• July 2026 blog post: 5 to 10 a day for new mailboxes, and 30 to 50 cold emails a day for aged, healthy ones.
• Older how-to, edited August 2026: at most 50 new leads per mailbox per day.
• September 2025 guide: 150 to 200 total emails per mailbox per day, “ideally less.” This is total sends, not new cold leads.

The safe reading is 30 net new leads per mailbox per day, unless your data supports more. To send more, add mailboxes and domains, as Amplemarket advises.

• Avoid spikes. Both Google and Amplemarket warn against sudden jumps.
• Back off on errors. Google says to “reduce the sending volume” if messages start bouncing or being deferred.
• Watch your ratio. Amplemarket advises keeping sent-to-received below 4.

Step 8: Keep your list clean

Before sending:

1. Validate every address before it enters a sequence.
2. Remove bounced addresses automatically. Google says to “automatically unsubscribe recipients who have multiple bounced messages.” For cold mail, one hard bounce is enough.
3. Monitor inactive recipients and remove invalid ones promptly, as Yahoo recommends.
4. Exclude customers, current deals, past opt-outs and anyone who said no.
5. Avoid purchased lists. Google and Yahoo both advise against them.

Amplemarket’s guide calls a bounce rate under 10% “safe” for cold outbound, while its product page advertises an average under 3%. Aim lower. Amplemarket’s Email Validation checks addresses in real time, and its pricing article says validating an email uses 0.5 credits. Its Workflows can move bounced or spam-hit leads to an exclusion list automatically.

Step 9: Write email that looks like one person wrote to another

Reputation and list quality do most of the work, but content is easy to get wrong.

• Be honest. Google says deceptive subject lines, sender names and reply-to addresses are against Gmail policy. The FTC also bars deceptive subject lines.
• Limit links and images. Amplemarket’s how-to says these are typical of marketing mail. One link is usually enough.
• Make links readable. Google says links in the body should be “visible and easy to understand.”
• Hide nothing. Google says not to use HTML and CSS to hide content.
• Use a custom tracking domain. Amplemarket says open tracking uses a shared domain by default and that its custom tracking setup (a CNAME record) keeps your email links on your own domain.
• Consider turning off open tracking. Amplemarket’s guide says tracking pixels can trigger security gateways in finance, healthcare and government. For those prospects it suggests using reply rate as your main metric.

Step 10: Include an unsubscribe option in every email

People who can’t easily opt out are more likely to hit “report spam.” Under the FTC’s CAN-SPAM guide, commercial email must:

• Include a clear way to opt out, which must work for at least 30 days after sending.
• Honor requests within 10 business days.
• Include your valid physical postal address.
• Use accurate header information and honest subject lines.

The FTC says each violating email can draw penalties of up to $53,088, a figure it notes was updated in January 2024.

What about one-click unsubscribe?

Google’s FAQ says one-click is “required only for marketing and promotional messages,” and transactional mail is excluded. The FAQ does not address cold or one-to-one outreach directly. A sales pitch looks promotional to us, so treat it that way if you could reach bulk volume.

In the Amplemarket docs we read, we did not find a page describing a one-click List-Unsubscribe header for sequences, and its compliance article does not mention one either. Ask sales directly before you buy if this matters at your volume. At minimum, add a plain line such as “Not relevant? Reply ‘no’ and I won’t email again,” then actually honor it.

Step 11: Monitor Postmaster Tools and placement every week

Setting up Google Postmaster Tools is free.

1. Sign in and add the domain you authenticate with (your DKIM d= domain or SPF Return-Path domain).
2. Copy the TXT or CNAME record into your DNS and click Verify. Google says the status can take up to 10 minutes to update.
3. Open the dashboards.

Google’s dashboard page lists eight. The ones to check weekly:

• Spam rate: your share of inbox mail marked as spam. Target below 0.1%, and treat 0.3% as the wall. Google’s FAQ says that above 0.3% bulk senders lose eligibility for mitigation until the rate stays below it for 7 straight days.
• Compliance status: shows whether your mail meets Gmail’s requirements. It reports on primary domains only.
• Domain reputation and IP reputation: quality ratings for your domains and sending IPs.
• Authentication and delivery errors: pass rates, rejections and temporary failures.

The catch for small senders: Google says data might be missing when daily volume is too low. Low-volume cold senders may see empty dashboards, so an empty dashboard doesn’t mean all is well. Postmaster Tools also covers only Gmail, so keep your own weekly bounce, reply and opt-out numbers by mailbox. For Yahoo, enroll in its Complaint Feedback Loop, which Yahoo says is needed for all DKIM domains.

What Amplemarket’s deliverability features do

Amplemarket is a full outbound platform with data, sequences and a dialer, so deliverability is one part of what you pay for. It sends through your own mailbox. Its Gmail integration page says “every email goes out from your actual inbox,” so SPF, DKIM and DMARC remain yours to set up. Here is what its own pages describe. We have not run these tools ourselves.

Feature	What Amplemarket says it does	Checklist step
Domain Health Center	One dashboard for SPF, DKIM and DMARC status, sending volume, ratio, spam tests, blacklist monitoring and warmup progress	2 to 4, 7, 11
Deliverability Booster	Warmup through a controlled network, for new mailboxes, existing mailboxes and spam-flagged ones. Works with Google Workspace and Microsoft	6
Email Spam Checker	Weekly placement tests of connected mailboxes, labeling each healthy or unhealthy. For a flagged mailbox, it advises pausing outreach, running the Booster and holding volume until a later test passes	11
Mailbox Recommendation	Uses test results and domain health to suggest which mailbox to send from	7, 11
Rotation and auto ramp-up	Spreads sends across mailboxes. New ones start low and rise over several weeks. Setting limits manually turns off the auto ramp	6, 7
Email Validation	Real-time address checks before leads enter a sequence	8
Workflows	Can move bounced or spam-hit leads to an exclusion list	8

How to read the vendor’s numbers

The Domain Health Center page lists an average 78%+ open rate, under 3% bounce rate and under 2% spam rate. It gives no sample, period or method. Do not compare that spam figure with Google’s 0.3%, because the page does not define it and it may not be the same metric.

Also, the product page says Amplemarket scored 21 out of 21 in “independent feature evaluations,” while its blog describes this as its own audit.

Amplemarket pricing (as of November 2026)

Plan	Price	Users included	Contacts	Mailboxes per user (from)
Startup	$600 per month, annual term	2	27,000	2
Growth	Custom	4	140,000	4
Elite	Custom	10	400,000	8

• Minimum commitment: $600 a month on an annual term works out to $7,200 a year before any extra seats.
• Check before buying: the pricing page appears to show Email Spam Checker and Mailbox Recommendation on only two of three plans, without clear labels in the text we read. Amplemarket’s pricing article says Growth and Elite add them, but its own comparison table lists the checker on all plans. Ask sales for this in writing.
• Credit figures differ: the pricing page lists 13,500 email credits per user per year on Startup, while the March 2026 article says 15,000.
• Trial: all plans include a free trial, and the article mentions 14 days.

Who should not buy Amplemarket

• Solo founders sending a handful of cold emails a week. Setting up DNS and following this checklist by hand is cheaper.
• Teams that only need warmup. A $7,200 annual commitment is a lot for that one feature.
• Businesses whose lists are all opt-in, who need an email service rather than a sales platform.

If you are still comparing outbound platforms, our guide to the best sales prospecting tools for small B2B teams sets Amplemarket against Apollo.io and Seamless.AI.

Where SMTP2GO fits, and where it does not

Do not use SMTP2GO for cold email. SMTP2GO prohibits it, and it says so directly.

• Its migration FAQ asks “Can we send cold emails?” and answers: “No, our Terms of Service prohibit sending cold emails.” It adds: “We require that all sending is to 100% opt-in recipients only.”
• Its terms say: “We forbid the use of the service to send unsolicited mass emails or unsolicited emails of any kind.”
• Its contract terms rule out purchased lists and “marketing leads (including lists built via LinkedIn or obtained from a 3rd party).”
• Its new account article says all new accounts are reviewed after an initial 1,000-email quota. Its terms allow suspension or termination for violations.

Routing a prospecting list through it breaks its rules and risks your account.

What SMTP2GO is good for

SMTP2GO is an SMTP relay for mail people expect: password resets, receipts, order notifications, form alerts and opt-in marketing. It belongs alongside your cold setup, not inside it.

• Separate streams: keep transactional mail on your main domain or its own subdomain, and cold outreach on a different domain with its own mailboxes. Yahoo advises against sending bulk or marketing mail from the same IPs used for transactional mail, and Google says to use a different IP for each message type if you send from several.
• Authentication: SMTP2GO’s FAQ says SPF and DKIM are handled with a few CNAME records. Google’s guidelines say to verify that any email provider authenticates your domain.
• Opt-in lists: its terms require a current, 100% opt-in list with an unsubscribe link in each email.
• WordPress: if your site’s order and password emails go to spam, see our guide to fixing WordPress and WooCommerce emails with SMTP2GO.

SMTP2GO pricing (as of November 2026)

Plan	Monthly	Yearly	Emails per month
Free	$0	n/a	1,000 (limit of 200 per day)
Starter	$10	$100	10,000
Professional	$75	$750	100,000, with a dedicated IP
Premier	Custom	Not stated	Over 3,000,000

Small inconsistency: the pricing page and homepage also show “$79 / month” and “$948 / year” in a signup dialog without naming a plan, and the Premier column shows $75 alongside “Custom.” Confirm at checkout. The free plan needs no credit card, and verifying your sender domain removes its hourly cap, per SMTP2GO’s FAQ.

Track it all somewhere your team will actually look

A simple table of domains and mailboxes, with fields for warmup start date, daily cap, last spam test and DNS status, is enough. A plain database in Notion works well for this, and you can keep it next to your pipeline.

If you want a pipeline to go with it, our Sales CRM for Business Notion template includes companies, contacts, deals and interaction logs, with views for overdue follow-ups and stale deals. Deliverability tracking is a table you would add yourself.

FAQ

Is cold email legal?

In the US, CAN-SPAM allows commercial email if you follow its rules, including opt-out, a physical address and honest headers, and the FTC says B2B mail is not exempt. Amplemarket’s article argues GDPR generally permits it with a legitimate reason and a clear opt-out, but that is a vendor’s view. Rules vary by country, so ask a lawyer about your own markets.

Can I send cold email through SMTP2GO?

No. Its help center says, “our Terms of Service prohibit sending cold emails,” and it requires 100% opt-in recipients. Use it for transactional and opt-in mail, on a separate domain from your cold outreach.

Do Google’s bulk sender rules apply if I send under 5,000 emails a day?

The bulk rules kick in at close to 5,000 messages to personal Gmail accounts in 24 hours, counted across a primary domain. The all-sender rules still apply below that: SPF or DKIM, valid DNS, TLS and a spam rate under 0.3%. Yahoo gives no number at all.

How many cold emails can I send per mailbox per day?

Neither Google nor Yahoo publishes a figure. Amplemarket’s help article recommends up to 30 net new leads per day after a 12-week ramp, and its other pages give figures up to 50. Start lower, and raise volume only when your bounce and spam numbers are clean.

Is DMARC at p=none good enough in 2026?

Yes, for the requirement. Both Google and Yahoo accept p=none as the minimum, and Yahoo adds that DMARC must pass. Tightening the policy later is a good step once reports show your legitimate mail passes consistently.

Do the setup steps this week, then treat the rest as a weekly routine. If you run outbound at a scale where a shared dashboard saves real time, Amplemarket is worth a trial. If not, this checklist costs nothing to follow.