Free Cold Email Spam Checker
Verify the list before you send the copy
Bounces from dead addresses are a bigger deliverability risk than trigger words. Cleanlist AI verifies the whole list, at half a credit per email.
Working a whole list? Upload the CSV to Cleanlist AI. Get 14 days of Pro, free: 250 credits, 3 seats, agents, Sequences and Clu in Slack.
Start free trialLearn what routes a cold email to spam before you send it: trigger words, formatting and links, plus the bounce rate that matters more than any of them. Cleanlist AI verifies the list so your copy reaches real mailboxes.
Verify the list before you send the copy
Bounces from dead addresses are a bigger deliverability risk than trigger words. Cleanlist AI verifies the whole list before you send, at half a credit per address.
The Free plan is $0 with 50 credits a month and 5 searches. Every new workspace can also try Pro free for 14 days.
- Search
- Free
- Verified work email
- 1 credit
- Phone number
- 10 credits
98% verified work emails and 85% phone numbers on our 500-lead benchmark, across 25+ providers.
A demo of Clu, the Cleanlist AI agent, doing this for a whole list. Asked: Verify every email in Series B sales leaders before Monday's send. Clu runs the tools, asks for confirmation before spending credits (Validate 480 emails on Series B sales leaders, 240 credits), fills the list row by row and reports: 480 checked: 431 verified, 33 risky, 16 invalid. Want me to drop the invalid ones before Monday?
10,000+ users, from founders to full sales teams
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The Cleanlist AI Chrome extension finds the verified email and phone number for the LinkedIn profile you have open, in the same tab.
Email spam checker, explained
An email spam checker scores your message before you send it and flags the words and formatting that route cold email to the spam folder. Read your subject and body for trigger words, ALL-CAPS and extra links, then fix what you find. Clean copy helps, but bounces from a dirty list are the bigger risk.
The toolFree Cold Email Spam CheckerRunsInside Cleanlist AIFree quotaAccount required
How does this tool work?
A cold email spam checker analyzes your message before you hit send and scores how likely it is to land in the inbox versus the spam folder. Spam filters punish a familiar set of things: trigger words (free, guarantee, act now, limited time), excessive punctuation and ALL-CAPS, too many links, urgency and money language, weak openers, and structural red flags.
You can review a draft for all of them by hand before it goes into a sequence.
Why outbound teams test copy first: spam filters at Google and Microsoft read your content and compare it against patterns from billions of flagged messages. A single spammy subject line can route an otherwise good campaign straight to junk, where it gets zero replies and silently drags down your sender reputation.
Catching the triggers before you send is far cheaper than burning a domain.
The part a content check can't fix: clean copy is necessary but not sufficient. The single biggest deliverability killer in cold outreach is your LIST. Sending to invalid, outdated, or spam-trap addresses produces bounces, and bounce rate is the metric mailbox providers weigh most heavily when deciding whether you're a spammer.
You can write a perfect email and still get blacklisted if 15% of your list is dead. Cognism estimates B2B contact data decays at roughly 22.5% a year, so a list that was clean six months ago is already a liability.
This is where Cleanlist AI comes in. Its email verification checks every address with an SMTP mailbox check and catch-all detection before you send, at half a credit per email, so dead addresses don't count against your domain. Pair a verified list with inbox-safe copy and you protect the asset that every cold campaign depends on.
For sending-domain checks, also run the email blacklist checker to confirm your domain isn't already flagged.
How email spam scoring works
Spam filters at Google and Microsoft read every message and compare it against patterns from billions of flagged emails, then assign it a score. A spam checker approximates that logic against the signals filters weigh most: trigger words (free, guarantee, act now), urgency and money language, ALL-CAPS and excessive punctuation, link density, weak openers, and length.
Each signal adds risk, and a checker rolls them into a single score. A bad score does not guarantee a filter will junk you, it means you are carrying avoidable risk that is cheap to remove before you send.
How to fix a high spam score
Work down the flagged list from the biggest offenders. Swap trigger words for plain language ("free trial" becomes "try it", "act now" becomes "this week"), cut exclamation points and ALL-CAPS, and keep links to one or two. Lead with a specific, human first line instead of "Dear Sir/Madam", and keep the email short.
Then fix what copy cannot: your list. The single biggest deliverability factor is bounce rate, so verify addresses with the email verifier before you send, and confirm your domain is not flagged with the email blacklist checker. For the full playbook, see how to reduce email bounce rate.
Who uses the Free Cold Email Spam Checker?
The people who run it most, and what each one runs it for.
- SDRs & BDRsPressure-test cold email copy before a sequence goes live.
- Demand genProtect deliverability across high-volume outbound campaigns.
- FoundersSanity-check founder-led outbound before emailing prospects.
- AgenciesVet client cold email drafts before they touch a sending domain.
What does Cleanlist AI do with a whole list?
Watch a real search go from query to an enriched, validated, CRM-ready list: 36 leads, 100% contact fill, synced to HubSpot.
36 ICP leads, 100% contact fill, validated and pushed to HubSpot in one flow
Describe the job once. An agent runs it every week.
Clu turns one sentence into an agent. It searches 1B+ profiles, finds verified emails and phone numbers across 25+ providers, adds the people to your sequence and posts each run to Slack.
Weekly ICP outbound
Built by Clu from: “Every week, find 500 new people who match my ICP, get their emails and phones, and add them to Series B outbound.”
- Searched 1B+ profiles for new ICP matches500 foundPeople Search
- Ran the waterfall across 25+ providers487 emails · 412 phonesWaterfall
- Verified every email and phoneSMTP + catch-allVerification
- Added them to Series B outbound500 peopleSequences
- Posted the run to #pipelineSlackAgents
Friday 4:52 PM15 replies · 5 calls booked
Everything in the 14-day Pro trial
- Clu and agentsDescribe the job in one sentence. Clu builds the agent, runs it on a schedule or a CRM trigger and posts every run to Slack.
- People and Company SearchFind your buyers in 1B+ profiles from one sentence. Searching costs 0 credits.
- Waterfall enrichmentAsk 25+ providers in order and stop at the first verified email or phone number. 98% verified work emails and 85% phone numbers on a 500-lead benchmark.
- Email verificationRun SMTP and catch-all checks on every address before it reaches a sequence, at half a credit an email.
- ICP scoringScore every lead 0 to 100 against your ICP, with the reasons written down. The Research and Qualification skills do the digging.
- SequencesSend email from your reps' own inboxes, with call tasks. A reply stops the sequence. Sending costs 0 credits.
- CRM syncTwo-way sync with HubSpot, Salesforce and Pipedrive. Push finished lists to Outreach, Salesloft and Lemlist.
- Chrome extensionGet a verified email and phone number in one click on LinkedIn, Sales Navigator, Salesforce and HubSpot.
- MCP and APIRun the same search and waterfall from Claude or ChatGPT with 36 MCP tools, or from your own code with the REST API.
14 days of Pro, free: 250 credits, 3 seats, agents, Sequences and Clu in Slack. Then Free at 50 credits a month, or Starter at $49 and Pro at $89 a seat a month.
Which free email lookup tools work together?
Start from whatever you have (a name, a domain, an email or a block of text) and chain the tools until you have a verified contact.
- Email Verifieremailmailbox statusCheck the mailbox with SMTP and catch-all detection before bounces hurt your sender reputation. 2 free checks per IP every 30 days.
- Email Blacklist Checkerdomain, email or IPblocklist statusTest your domain or IP against 9 major DNS blocklists in seconds.
- MX LookupdomainMX recordsConfirm your mail servers and SPF records are configured correctly.
- Email Syntax ValidatorWhat makes an address well formed under RFC 5322, and the typos to look for.
- AI Cold Email GeneratorThree frameworks that beat starting from a blank page: AIDA, PAS and the pattern interrupt.
- Email Signature GeneratorWhat a professional signature should include, and how to add one in Gmail and Outlook.
Which paid tool does this for a whole database?
We compared the platforms that do this job for a whole database, Cleanlist AI included, and say where each one falls short.
- Best data enrichment toolsThe enrichment platforms side by side: coverage, credit costs and what each one verifies.
- Best sales prospecting toolsProspecting tools ranked by how fast a rep gets from an ICP to a list they can contact.
- Sales sequencesSix complete sales sequences with day-by-day timing, the stop rules and the software that runs them.
Frequently asked questions
Short answers about the Free Cold Email Spam Checker: what it checks, what it costs and where it stops.
All free toolsHow does an email spam checker work?
A spam checker scans your subject line and body against known spam-filter triggers: flagged words and phrases (free, guarantee, urgency and money language), ALL-CAPS and excessive punctuation, link density, weak or salesy openers, and length problems. Then it points out what to fix. You can run the same review by hand before a draft goes into a sequence.
Will a good spam score guarantee my email reaches the inbox?
No, and this is the key thing teams miss. Clean copy gets you past content filters, but the biggest deliverability factor in cold outreach is your bounce rate, which comes from your LIST, not your words. Sending to invalid or outdated addresses triggers reputation penalties that route even perfect emails to spam. Verify your list before you send. Cleanlist AI checks the mailbox behind every address with an SMTP check and catch-all detection, at half a credit per email.
What words trigger spam filters in cold email?
Common triggers include urgency phrases (act now, limited time, urgent), money and free language (free, guarantee, no cost, $$$), salesy hype (amazing, incredible, risk-free), weak openers (Dear Sir/Madam), and structural signals like ALL-CAPS words, multiple exclamation points, and too many links. Search your draft for each one and swap it for plain language.
Why do my cold emails go to spam even with clean copy?
Almost always because of list quality, not copy. If a meaningful share of your list bounces, mailbox providers flag you as a likely spammer and start filtering all your mail. Other causes: a blacklisted sending domain (check it with the free blacklist checker), missing SPF/DKIM/DMARC authentication, and sending volume that ramps too fast. Fixing copy helps, but verifying your list is the highest-leverage fix for most senders.
What is a good email spam score?
Lower risk is better, and each checker scales its score differently, so compare like with like. What matters is that no high-severity triggers remain. A weak result means your copy is carrying avoidable risk, usually trigger words, ALL-CAPS, too many links, or a weak opener, that pushes you toward the spam folder. Fix those, then confirm your list is verified before you send.
Does an email spam checker guarantee inbox placement?
No. A clean score clears the content hurdle, but inbox placement also depends on your bounce rate, sender authentication (SPF, DKIM, DMARC), sending volume, and whether your domain is blacklisted. The highest-leverage move is keeping your list clean so you never bounce, then pairing verified addresses with inbox-safe copy. Check your domain with the free email blacklist checker for the full picture.
Now run it on the whole list.
Upload the CSV or describe the list you want. Clu finds, verifies and qualifies every row.
14 days of Pro, free.