> ## Documentation Index
> Fetch the complete documentation index at: https://docs.contiguity.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Caveats & Limits

> Rate limits, link preview quirks, and behavior that can get a number flagged.

## Rate limits

Each leased number is capped at **1 message per second sustained**, with short bursts allowed up to **5 messages per second**. This limit applies per line, not per account, so the way to send faster overall is to lease and [pool more numbers](/kb/compliance/imessage/strategies/outbound-first#scaling-with-number-pooling) rather than push harder on one.

While Contiguity doesn't enforce contact restrictions, we recommend the following:

| Strategy           | Limit Type                                             | Limit       |
| ------------------ | ------------------------------------------------------ | ----------- |
| **Outbound-first** | New contacts / line / day                              | Up to 100\* |
|                    | New contacts / line / hour                             | 20          |
|                    |                                                        |             |
| **Inbound-first**  | Reply to new contacts within 24h / line / day          | Unlimited   |
|                    | Reply to contacts after 24h of inactivity / line / day | 1,000       |

\* 100 new contacts per line per day is based on a warmed up number with a good reputation. Contiguity recommends ramping volume slowly over the course of a few weeks.

Furthermore, we recommend sending during normal daytime hours in the recipient's timezone.

<Note>
  Need to send faster than this on a single number? The `fast_track` option on `imessage.send` bypasses the recommended rate limit, but requires the Fast Track entitlement.
</Note>

## Links

Apple only expands link previews when the sender is already in the recipient's contacts. Until then, your links show up as plain, unstyled text. This is a limitation of iMessage itself, not something Contiguity can change.

Since the limitation is "not in contacts," the fix is to get yourself into their contacts. Send an Apple contact card (a `.vcf` file) early in the conversation. The recipient can save it with one tap, and from then on your links preview normally and your messages show your name instead of a bare number. If you don't already have a `.vcf` for your business, [vcard.free](https://vcard.free/) generates one for free, in your browser, with no signup.

A contact card is just another attachment on a normal send:

```typescript theme={null}
await contiguity.imessage.send({
  to: "+1234567890",
  message: "Save my info so links and previews show up correctly:",
  attachments: ["https://example.com/business-card.vcf"]
});
```

## What can get a number flagged or restricted

<AccordionGroup>
  <Accordion title="Mass unsolicited blasts" icon="ban">
    Sending unsolicited marketing messages to a purchased or scraped contact list is the single fastest way to get a number flagged. This applies even if the content itself would otherwise be fine.
  </Accordion>

  <Accordion title="Identical broadcast content" icon="copy">
    Sending the same message body to a large number of recipients in a short window, with no personalization, reads as a broadcast rather than a conversation.
  </Accordion>

  <Accordion title="High volume to brand-new contacts" icon="user-plus">
    Messaging a large number of people you've never had a conversation with, especially in a short window, is a strong spam signal, even if each message is unique.
  </Accordion>

  <Accordion title="Rapid recipient switching" icon="shuffle">
    Real conversations happen over time with pauses in between. Sending to a long list of sequential or unrelated numbers back-to-back, with no replies in between, looks like automation rather than a human having conversations.
  </Accordion>

  <Accordion title="Ignoring opt-outs" icon="hand">
    Continuing to message a recipient after they've asked you to stop is both a compliance issue and a strong negative signal for your number's health. Recipients who feel spammed are also more likely to report messages as junk.
  </Accordion>
</AccordionGroup>

<Note>
  The rule of thumb: if a message would be welcome and expected by the person receiving it, it's almost certainly fine. These guidelines exist for behavior that looks like spam, not for legitimate, opted-in business communication.
</Note>

***

Still have questions? Join our [Discord community](https://discord.gg/Z9K5XAsS7H) or email us at [help@contiguity.support](mailto:help@contiguity.support).

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