First-message checker

Paste the first message you plan to send someone who has not written to you, and pick the channel. The checker counts the characters, looks for links, phone numbers and email addresses, and checks that it asks a question; on iMessage a first message must be plain text under 300 characters.

Runs in your browser. Nothing you enter is sent anywhere or saved.

Why the first message matters

The first message in a new conversation is the one platforms look at hardest. Many new chats that nobody answers is what WhatsApp watches for, and iMessage numbers are blocked for messages people do not answer. A short, personal message that invites a reply protects your account and is more pleasant to receive.

This checker reads a draft and tells you what to fix before your AI agent sends it. It uses the rules and guidance Spaces publishes on its limits pages, and nothing else.

ChannelYour first message110 characters (must be under 300 on iMessage)

This passes the first-message rules for iMessage.

Under 300 characters (Good)110 characters. Inside the iMessage first-message limit.
No links (Good)No links found.
No phone numbers (Good)No phone numbers found.
No email addresses (Good)No email addresses found.
Invites a reply (Good)It asks a question, which gives the person an easy reason to answer.
Reads like a conversation (Good)No shouting in capitals or repeated exclamation marks.

The iMessage first-message rule

iMessage is coming soon to Spaces, and it has the strictest rule of any channel. Until someone replies, a first message must be plain text under 300 characters with no links, and at most 6 messages go out. The guidance also says to leave out photos, phone numbers and email addresses. Once the person answers, the conversation is normal and you can send what you need.

Apple publishes no limits for iMessage and a blocked number cannot be appealed, which is why Spaces stays far below its provider’s own caps. Choose iMessage above to check a draft against this rule.

Good first messages on every channel

On WhatsApp, Instagram, LinkedIn, Messenger, X and Email there is no character rule for first messages, but the same habits help everywhere:

Mention something the person already knows about: a booking, a quote they asked for, an order.
End with an easy question they can answer in a word or two.
Write it to one person. Spaces refuses the same cold message sent to many people.
Leave links and prices for the reply, once they have answered.
Only message people who expect to hear from you. Any message to someone who said stop is refused.

What each check means

Some checks are rules for a first iMessage, which must be fixed before it can go out. The rest are advice you can weigh up for yourself:

Length: on iMessage the first message must stay under 300 characters. Elsewhere the count is shown as a guide.
Links, phone numbers and email addresses: not allowed in a first iMessage. On other channels they are tips, because a first message reads better without them.
Invites a reply: the message asks a question. Without one, many people read it and move on.
Reads like a conversation: no words in capitals and no rows of exclamation marks, which make a message look like an advert.

A weak and a better example

Names and details are examples. “Big SALE this weekend!!! 20 per cent off everything, click the link” reads like an advert and gives nobody a reason to reply. “Hi Sam, it’s Maria from the bakery. Your cake is ready for Saturday. Would you like to collect at 10am or 2pm?” mentions something Sam knows about and ends with a question. Paste both into the checker to see the difference.

The checker cannot see photos or know whether the person expects to hear from you, so treat a clean result as a good start rather than a guarantee.

FAQ

How long can a first iMessage be?

Under 300 characters, as plain text with no links, until the person replies. At most 6 messages go out before they answer.

Can I put a link in a first WhatsApp message?

WhatsApp has no rule against it in Spaces, but first messages that mention something the person knows about and ask a question get more replies. Send the link once they answer.

Why does it matter whether the message asks a question?

Replies build a healthy history for the account. Many new chats without replies is what platforms watch for, so write first messages that invite an answer.

Does this checker count emoji correctly?

It counts each character you can see as one, including most emoji. Some combined emoji may count as more than one.

Is iMessage available in Spaces now?

iMessage is coming soon. Spaces will set up a dedicated iMessage number for your business, with nothing to sign in to.

Does the checker send my message anywhere?

No. It runs entirely in your browser. Nothing you paste is sent to Spaces or saved.