> For the complete documentation index, see [llms.txt](https://help.proxidize.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.proxidize.com/proxidize-proxies/mobile-proxies/mobile-per-proxy/how-proxy-assignment-works-on-per-proxy-plans.md).
# How Proxy Assignment Works on Per Proxy Plans
How proxies are assigned on Per Proxy plans, whether they are dedicated to you, and what your location and ISP choices lock in.
Each proxy on a Per Proxy plan runs through its own upstream device, and your location and ISP choices decide which device it can use.
This article explains how that works underneath, whether your proxies are dedicated to you, and the one choice that can leave a proxy stuck.
### Is my proxy dedicated to me?
Within your own account, yes. Across accounts, almost always, and by design rather than by accident.
#### Within your account
No two proxies in your account share an upstream device at the same time, so your proxies never overlap or interfere with each other.
#### Across accounts
Upstream devices are pooled across locations rather than permanently assigned to one account, and that is what allows you to switch location and ISP on demand.
Your proxy is on its own dedicated upstream the vast majority of the time, though on busy or congested locations there is a small chance of temporary sharing between accounts.
Either way your credentials never change, so sharing is never something you have to handle.
***
### What decides which device your proxy uses
Each proxy carries its own **Location** and **ISP** setting, both editable straight from its row, so you can retarget one proxy without touching the others.
#### Fastest
**Fastest** lets Proxidize pick the best performing option available at the time, and it is the recommended setting for most work.
Because nothing is pinned, rotations have the widest choice of upstreams, which makes this the more resilient setting.
#### A specific location or ISP
Choosing a specific city or ISP locks your proxy to it, and every future rotation stays within that choice, including rotations you did not trigger yourself such as a scheduled interval.
That is exactly what you want when your work depends on a particular city or network, and it is worth knowing what happens when the thing you pinned has a bad day.
{% hint style="warning" %}
**A pinned choice narrows what your proxy can fall back on.**
If a pinned **location** becomes unavailable, switch the proxy to one of the available locations to get it working again.
The dashboard warns you when you pin a specific ISP: doing so limits the fallback options, and if no connections become available in your location the proxy is disconnected until you reset the ISP selection.
{% endhint %}
***
### What rotation changes
A proxy rotates when you rotate it yourself, when its rotation interval comes due, or when you call its rotation URL.
In all three cases the proxy moves to a different upstream device and receives a new IP, within whatever filters you have set.
The switch happens on our side, so your hostname, port, username, and password all stay the same and no tool, script, or integration needs updating.
Your IP can also change without any rotation at all, because the ISP can reassign it on its own. That is a different thing, and nothing moves on our side when it happens.
| Event | What changes | What stays the same |
| -------------------------- | --------------------------------------- | ------------------------------------------------------- |
| A rotation | The upstream device, and the IP with it | Your credentials, and your location and ISP choices |
| An ISP reassigning your IP | The public IP only | The upstream device, your credentials, and your filters |
***
### Who controls the public IP
The last word on your public IP belongs to the mobile ISP, not to Proxidize.
Mobile ISPs use Carrier-Grade NAT, known as CGNAT, to manage their public IP pools, which is standard practice across mobile networks worldwide.
Because of it, two proxies on completely separate upstream devices can sometimes exit through the same public IP, depending on conditions inside the ISP.
The ISP can also change your public IP whenever its own conditions call for it, whether that is a handover between towers, congestion on the network, or an internal policy on how long an IP is held. In practice this tends to happen every 1 to 4 hours on an IP you never rotate.
Your proxy stays on the same upstream device through all of this, and your credentials and filters are untouched, so nothing needs updating on your side.
None of this is specific to Proxidize, and none of it is something we can override. What we control is which upstream device your traffic uses, and you control that through your filters and your rotation settings.
***
### Quick FAQ
Should I set a specific location, or leave it on Fastest?
Leave it on **Fastest** unless your work depends on a particular city or network. Fastest has the widest choice of upstreams to rotate onto, while a pinned proxy is limited to what you pinned it to.
My proxy stopped working and nothing on my side changed. What should I check first?
Check whether its location or ISP is pinned to a specific value rather than **Fastest**. If the location is pinned, move the proxy to an available location. If the ISP is pinned, reset the ISP selection.
Two of my proxies came out on the same IP. Is something wrong?
No. Mobile ISPs use CGNAT, so separate upstream devices can occasionally exit through the same public IP. Rotate one of them if you need the two to exit differently.
***
### Related articles
* [Mobile - Per Proxy](/proxidize-proxies/mobile-proxies/mobile-per-proxy.md)
* [Per Proxy - Pooling](/proxidize-proxies/mobile-proxies/mobile-per-proxy/per-proxy-pooling.md)
* [perProxy vs perGB](/proxidize-proxies/perproxy-vs-pergb.md)
***
### Need help?
If you have any questions, concerns, or need further clarification, feel free to reach out to us via live chat or email us directly at .
---
# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.
## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.
Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:
```
GET https://help.proxidize.com/proxidize-proxies/mobile-proxies/mobile-per-proxy/how-proxy-assignment-works-on-per-proxy-plans.md?ask=&goal=
```
`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.
Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.