Free SMS Spam Checker
Paste your message and see whether carriers are likely to filter it before you send. Keyword rules and a spam model, instant, no sign-up.
A strong indicator, not a guarantee. Every carrier applies its own private rules we can't see.
- Free, no sign-up, no limit
- Keyword rules plus a spam model
- Live GSM-7 and Unicode segment count
- Nothing stored
SMS isn't email
Email spam filters scan content and sender reputation. SMS carriers watch something different. A real person texting from their own phone is treated very differently from a business sending 50,000 messages through a shortcode.
Three signals matter most:
Volume patterns
How many messages, how fast
Reply ratios
Do people actually write back?
Sender type
Personal phone vs. business platform
Those three signals determine whether your message looks like a real conversation or a broadcast. Message content is just one part of the picture.
What gets your texts blocked?
Carriers don't share their rules, but these patterns appear in filtered messages.
Spam keywords
"Act now", "FREE", "Guaranteed", "Click here": lifted directly from email spam filter playbooks.
URL shorteners
bit.ly, tinyurl.com, and similar services are heavily scrutinized. Use a full domain instead.
Identical mass sends
The same text to 500 people word-for-word looks like a broadcast, not a conversation.
No personalization
Messages without a name or any variation look automated, even if you typed each one by hand.
No replies
A healthy person-to-person sender gets replies. If no one responds, carriers notice.
High send volume
Sending hundreds of messages per hour from a personal number triggers volume-based flags.
Why getting replies matters
Most SMS guides focus on content. But carriers also track how often people write back. A steady stream of replies tells carriers this is a real conversation, not a blast.
That's why QuickText routes replies to your personal phone, not a dashboard. When someone replies, you respond naturally. The ratio stays healthy.
Business SMS platforms route replies to a web dashboard. The conversation often dies there and the reply signal disappears. With QuickText, replies land in your messaging app, just like any normal text.
SMS spam words to avoid*
*well, sort of. Carriers don't ban individual words. They read the whole message, and a single flagged phrase in a real conversation rarely causes a problem.
Urgency
- act now
- urgent
- hurry
- limited time
- today only
- last chance
- deadline
- expires soon
- respond now
Financial / Prize
- free money
- you've won
- winner
- cash prize
- guaranteed income
- earn cash
- debt relief
- credit repair
- make $
Suspicious offers
- 100% free
- no cost
- no obligation
- risk-free
- no catch
- free gift
- no strings attached
- satisfaction guaranteed
Scam / phishing
- claim now
- you've been selected
- verify your account
- account suspended
- final notice
- you are a winner
- click to claim
Generic spam phrases
- click here
- click the link
- buy now
- order now
- shop now
- hot deal
- exclusive offer
- amazing offer
Overpromise / hype
- guaranteed
- 100% guaranteed
- proven results
- results guaranteed
- as seen on
- celebrity
- endorsed by
Both messages below use the word "free":
"Hey {{first_name}}, we have a free slot open this Tuesday. Want to grab it?"
"FREE OFFER!!! Act now, winner selected TODAY!!!"
Same word. One reads like a personal text. The other reads like a mass blast.
GSM-7 vs Unicode: the hidden SMS cost
Add one emoji to your message and the character limit drops from 160 to 70. That's not a bug. It's how SMS encoding works.
SMS has two encoding formats. Standard text uses GSM-7 (160 chars per SMS). The moment you include an emoji, a smart quote, or an em dash, it switches to Unicode, which cuts the limit to 70 characters per SMS.
| Encoding | Limit per SMS | Triggered by |
|---|---|---|
| GSM-7 (Standard) | 160 chars | Default for standard Latin characters |
| Unicode (UCS-2) | 70 chars | Any emoji, smart quote, em dash, ellipsis, or non-standard character |
When a message exceeds the limit it splits into multiple parts. Each part carries a small linking header, so the usable characters per part drop slightly: 153 for GSM-7, 67 for Unicode.
A simple example
You write a 140-character message with no special characters. That's 1 SMS. You add a thumbs up at the end. Now it's 140 Unicode characters. At 70 characters per SMS, that's 3 parts instead of one.
What triggers the switch?
- Emoji of any kind
- Smart quotes “ ” ‘ ’ : common when copying from Word or Google Docs
- The em dash — and the ellipsis …
- Accented characters outside the standard Latin alphabet (e.g. é, ñ, ü, ø)
Personal phone vs. business platform
There are two ways to send bulk SMS. Carriers treat them completely differently.
P2P (Person-to-Person)
- Messages send from your actual phone
- Uses your personal mobile number
- Looks like a regular text to carriers
- Replies land in your messaging app
- No platform registration required
- Treated as personal conversation traffic
A2P (Application-to-Person)
- Messages route through a commercial platform
- Uses a shortcode or 10DLC number
- Requires formal carrier registration
- Replies go to a web dashboard
- Mandatory STOP footer in every message
- Per-message fees apply
QuickText is P2P: your actual phone sends the messages. The CTIA defines P2P as low volume (roughly 15 messages/minute), under 1,000 per day, and bidirectional. Because the messages come from a real phone, carriers treat them like personal texts.
5 ways to improve SMS deliverability
Personalize every message
Use the recipient's name at minimum. Even one first-name field changes how the message reads to a carrier's pattern-detection system.
Vary your wording between sends
Sending the exact same message to 500 people looks like a broadcast. Change your opener, swap a phrase, reorder a sentence. Carriers see variation as a sign of individual conversations, not a bulk blast.
Use a conversational tone
Ask a question at the end. Messages that get replies prove to carriers that a real conversation is happening. Think of each text as the opening line of a conversation, not a broadcast.
Never use URL shorteners
bit.ly and similar services are among the highest-risk elements in any SMS message. Use your full domain URL instead.
Pace your sends
Firing 500 messages in 60 seconds looks automated no matter how personal the content. Spread sends over several hours and introduce random gaps between messages. That's what a real person texting looks like.
Want to check all these boxes at once? My free SMS template generator builds messages with built-in placeholder personalization and spin text variation already baked in.
How many texts per day is too many?
A perfectly written message can still get flagged if it arrives in a burst of 500 sends in five minutes. Volume and pace matter as much as content.
What the guidelines say
The CTIA's messaging guidelines put personal-phone traffic at roughly 15 messages per minute and under 1,000 per day. Go past those numbers and carriers start questioning whether the "personal" phone is really personal.
Real-world sweet spot: 100 to 400 per day
In practice, most people who stay off carrier radar send between 100 and 400 messages per day, spread across morning and afternoon.
messages/day, spread out
messages/day, depends on pace
messages/day or in bursts
Why random delays matter
If every message sends exactly 30 seconds apart, the pattern is machine-perfect. No human texts that way. A random gap between sends (45 seconds to 3 minutes) breaks the mechanical rhythm. The send log looks like a real person picking up their phone, not a scheduled broadcast.
QuickText includes a random delay feature. You set the range. QuickText handles the randomization. The result is a send pattern that mirrors how a real person would text.
Split sends across the day
150 in the morning, 150 in the afternoon. Early replies land before your second batch goes out, and your reply ratio stays healthy all day.
Is texting contacts legal?
Short answer: it depends on how you got the number and how you're sending.
US texting law centers on the TCPA (Telephone Consumer Protection Act), which was written mainly to stop robocalls and mass automated blasting. Its application to manual, personal-phone texting is more nuanced, and courts are still working it out.
The rough rule of thumb
- Purchased lists carry real legal risk regardless of the platform. This is where TCPA enforcement tends to focus.
- Warm contacts (people who gave you their number or have an existing relationship with you) are generally much lower risk.
- Texting from your own phone is treated differently than sending through a business SMS platform, but it doesn't exempt you from everything.
QuickText is built for warm outreach and real conversations, not cold blasting. But the legal responsibility is yours. If you're unsure, check with an attorney or the FCC's guide on unwanted texts.
Frequently asked questions
The questions that come up most often.
Two checks run on every message. A rule layer scans for known carrier filter triggers: spam phrases, URL shorteners, excessive caps, and encoding issues like smart quotes or em dashes. Then a machine learning model checks how closely the message resembles real-world spam based on word patterns, not just specific keywords. The model was trained on the UCI SMS Spam Collection, 5,574 messages hand-labeled by researchers, and reached 97.2% accuracy on messages it had never seen. Both results are combined into the final 0 to 100 score.
No single thing triggers a filter. Carriers look at a combination: spam keywords, URL shorteners, how fast you're sending, and whether people actually reply. It's the overall pattern that tips the scale. The checker above handles the content side of things.
The biggest offenders are urgency phrases ("Act now", "Hurry"), prize language ("You've won", "Cash prize"), generic commercial phrases ("Click here", "Buy now"), and anything that sounds like a guarantee. If it could run as a TV ad, don't put it in a text.
If you're sending through a business SMS platform, yes. If you're texting from your own phone with QuickText, the rules are different. Your messages come from a personal Android number, the same as any normal text. That said, always respect it when someone asks you to stop.
Carriers can't see inside your head. They see patterns. If your messages contain spam keywords, use URL shorteners, and get no replies, it looks automated no matter who wrote them. The fix: write naturally, vary your wording between sends, and give conversations time to generate replies.
Spintext is a way to vary your message automatically. [[Hi|Hello|Hey]] means each recipient gets one of those three words at random. Instead of sending "Hi" 500 times, every message is slightly different. Carriers see variation, not a broadcast. Combined with name personalization, it's one of the most effective things you can do. QuickText supports spintext natively.
With emojis, your message switches from GSM-7 (160 chars per SMS) to Unicode (70 chars per SMS). A 100-character message with one emoji becomes a 2-part SMS instead of one. The checker above detects this automatically and shows you the real segment count.
P2P (person-to-person) means your messages come from your actual phone, just like a normal text. A2P (application-to-person) means they route through a commercial platform using a shortcode or 10DLC number. Carriers treat them differently: P2P is judged by personal-phone standards, A2P requires registration and opt-in compliance.
10DLC is required for A2P messaging through business platforms. If you're texting from your own Android phone with QuickText, you're not on A2P infrastructure, so 10DLC doesn't apply the same way.
Many do. SMS gets roughly a 45% response rate for real estate, compared to single-digit email open rates. The main factors are how you got the number and what kind of contact it is. Warm leads who gave you their number are very different from a purchased list. QuickText is built for warm, conversational outreach.
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