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

# Rate Limits and Message Queues

At Arnio, we put safeguards in place to ensure **high message quality, reliable uptime, and compliance with Apple’s iMessage delivery standards**. These measures help protect our platform from abuse while giving businesses the scale they need to grow.

Our safeguards include:

* **Account-level quotas**
* **Dynamic rate limits**
* **Phone number pools**

## **Account-Level Quotas**

### **Enterprise Plans**

For larger organizations with higher messaging volume, our **Enterprise plans** provide flexible quotas that scale with your business. Enterprise access is granted on an application basis to maintain platform integrity and combat spam.

Each enterprise account starts with a quota based on your approved use case (usually defined as a monthly message limit). If you’re nearing your quota, you can request an increase.

* Requests for quota increases are typically fulfilled within **2 weeks per 1M additional monthly messages**.
* Example: A request to add 2M messages/month is guaranteed within 4 weeks, though we often fulfill much faster.

If you expect to need an increase of **100k+ messages per month**, please reach out to our support team [hello@arnio.co](mailto:hello@arnio.co)

***

## **Rate Limits**

Arnio enforces rate limits at both the **contact level** and the **conversation level** to ensure reliable delivery and compliance with Apple’s policies.

| **Limit Type**          | **Description**                                                                                                  | **Rate limit\***                                                                |
| ----------------------- | ---------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------- |
| New contact outreach    | Maximum number of unique contacts you can initiate per phone line, per day.                                      | 50 new contacts/day per line                                                    |
| Per-conversation limits | Once a conversation exists, you can continue messaging that contact, but each conversation is subject to pacing. | 20 messages/minute <br /><br />600 messages/hours<br /><br />2,400 messages/day |
| Message pacing per line | Each phone line can send at a rate of \~1 message per second. Scaling requires number pooling.                   | 1 message/second/line                                                           |

\*All limits are enforced per phone number.

### **Key Notes**

* If you have 10 phone lines, you can start **up to 500 new conversations/day** across your account.
* Ongoing conversations are not capped by Arnio in total, but each conversation must respect the pacing limits above.
* Arnio reserves the right to throttle or block accounts that exceed limits in ways that risk spam classification or service stability.

## **Number Pooling**

To reach more contacts or increase throughput beyond what a single phone line can handle, Arnio supports **number pooling**. By assigning multiple phone lines to your account, you can scale outbound messaging rates proportionally.

* Example: If you need to send \~100 messages per second, you would need 100 phone lines in your pool.
* Even though Arnio may deliver from any number in your pool, **each recipient always sees a consistent number**. If a customer first hears from you via +1 999 888 7777, all future conversations with that customer will stay on that number, ensuring continuity and trust.

## **Message Queueing**

Arnio automatically queues outbound messages as they reach our API.

* If you submit 10 requests simultaneously, they will be paced out at one message per second per line.
* Each account has a queue window of up to **1,500 pending messages**. Beyond this, Arnio will return a 429 - Too Many Requests response.
* Using number pooling allows you to expand throughput and reduce queue delays.

***

## **Messaging Limits**

Messaging limits are based on how phone lines are attached to your account.

* If you exceed your plan’s monthly allowance, Arnio will **not hard-stop your messages**.
* Additional usage will be billed at **\$0.015 per message**
* For rapidly growing accounts, we strongly recommend upgrading your plan early to secure the **lowest possible cost per message**.