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

# Phone numbers & limits

What you get on day one, and what to ask for when you outgrow it.

## Phone numbers

**Outbound calls use our pool of Pakistani numbers** by default, so a customer may see a different number on each call.

Want **a number of your own**? Email [founders@upliftai.org](mailto:founders@upliftai.org) and we assign one **within a day**. Depending on your setup, it can take [inbound calls](/voice-agents/calling/inbound) too.

## Limits

| Area        | Limit                                                                | Default                                                                                                                                 |
| ----------- | -------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------- |
| Phone calls | Calls in parallel                                                    | **1**, shared by inbound and outbound. Raised on request, into the **thousands** — see [concurrency](/voice-agents/calling/concurrency) |
| Campaigns   | Number of campaigns                                                  | Unlimited                                                                                                                               |
| Team        | Team members                                                         | Unlimited                                                                                                                               |
| API         | Request rate                                                         | 150 requests per minute, per endpoint                                                                                                   |
| Contacts    | Per [append](/api-reference/campaigns/append-contacts-to-a-campaign) | 1,000 inline, 5,000 from a file or sheet                                                                                                |
| Contacts    | File upload                                                          | 10 MB, CSV or Excel `.xlsx`                                                                                                             |
| Contacts    | Attributes per contact                                               | 1,500 bytes                                                                                                                             |
| Calls       | `additionalInstructions`                                             | 2,000 characters                                                                                                                        |
| Calls       | `variables`                                                          | 3,000 characters, keys up to 64. The model sees up to 30 fields, 160 characters each                                                    |
| Tools       | [Webhook tool](/voice-agents/tools/webhook-tools) answer             | 10 seconds                                                                                                                              |
| Webhooks    | Delivery answer                                                      | 10 seconds, 4 attempts                                                                                                                  |
| Records     | Sessions and failed deliveries                                       | Kept 90 days                                                                                                                            |
| Records     | Recording link (`audioUrl`)                                          | Valid 1 hour                                                                                                                            |

**Need more?** Every limit can be raised on request. Email [founders@upliftai.org](mailto:founders@upliftai.org) with your use case.