Bitelio
§ T-03  —  Tool← All tools

Email spam
checker

Paste in your subject line and body copy to uncover trigger words, punctuation red flags, and the other patterns that get email routed to spam.

Analyze email content
§ 01Spam factors

What sends email to spam.

Filters weigh dozens of signals — your copy is only one of them.

Spam trigger words

Phrases like "free", "guaranteed", "click here", and "act now" carry heavy filter penalties — a couple of them can be enough to tip a borderline message.

Missing authentication

If SPF, DKIM, and DMARC aren't in place, receiving servers can't confirm the mail is really yours. Failed authentication is the single biggest driver of spam placement.

Poor sender reputation

Providers keep a running score based on your bounces, complaints, and engagement history. Once that score slips, even flawless emails get junked.

Excessive capitalization

SUBJECT LINES WRITTEN IN ALL CAPS read as shouting, and filters punish them hard. Stick to sentence case.

High bounce & complaint rates

Each bounced address and each "report spam" click counts against your domain, making every subsequent send harder to deliver.

Purchased email lists

Bought lists are riddled with dead addresses, stale data, and spam traps — a fast track to a ruined sender reputation.

Land in inboxes, not junk folders.

Authentication is the deliverability factor that matters most, and Bitelio sets up SPF, DKIM, and DMARC for you. Free to start — no credit card needed.

Start with BitelioDeliverability guide

Frequently asked questions

What is a spam checker?

A spam checker inspects your subject line and body copy for the signals inbox providers weigh when deciding whether to junk a message — trigger phrases, over-capitalization, suspicious punctuation, and similar red flags. Testing your email before it goes out gives you the chance to fix problems while they are still cheap to fix, which directly helps deliverability.

What causes emails to go to spam?

Plenty of things: trigger words in your copy, a weak sender reputation, absent SPF/DKIM/DMARC records, high bounce rates from purchased or unengaged lists, too many links or images, a skewed HTML-to-text ratio, or recipients having flagged your earlier messages. Of all of these, broken authentication and poor sender reputation do the most damage.

How do I check if my email will be spam?

Start with a content test like this tool, which scores your subject line and copy. Then confirm SPF, DKIM, and DMARC are set up correctly on your domain, run test sends through a spam-testing service, and keep an eye on bounce and complaint rates as your sending history grows.

What are spam trigger words?

They are phrases that filters have learned to associate with junk mail — "free", "guaranteed", "act now", "click here", "make money", "winner", "prize", "urgent", and hundreds more. Each occurrence adds points to a message's spam score, and crossing the threshold gets it flagged or blocked. Writing in plain, conversational language keeps that score low.

Is email authentication important for avoiding spam?

Absolutely. SPF, DKIM, and DMARC are how receiving servers confirm your mail is genuine; without them, nothing distinguishes you from a spoofing attempt, so filters treat you with suspicion. Gmail and Yahoo have required DMARC for bulk senders since 2024, and authenticated mail from a domain with a clean reputation reaches the inbox far more consistently.