> For the complete documentation index, see [llms.txt](https://docs.helodata.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.helodata.com/getting-started/how-proxies-work.md).

# How proxies work

A proxy is an intermediate server that forwards your HTTP(S) requests to a target site. The target sees the proxy's IP, not yours. helodata operates pools of proxies sourced from real residential, mobile, and ISP networks worldwide.

## Request lifecycle

```
┌─────────┐         ┌──────────────────┐         ┌──────────────┐
│  Your   │  HTTP   │  helodata proxy  │  HTTP   │   Target     │
│  app    ├────────►│  gateway         ├────────►│   website    │
│         │◄────────┤                  │◄────────┤              │
└─────────┘         └──────────────────┘         └──────────────┘
```

1. Your application sends a request to `gate.helodata.io:7777` with credentials.
2. For **gateway products** (Residential, Mobile), the gateway parses your [username string](/getting-started/username-format.md), authenticates the sub-user, then selects a backend IP matching the requested `type`, `region`, `state`, `city`, `asn`, and `session`. For **ISP proxies**, your client connects directly to a specific IP from your purchased list — no gateway routing.
3. The target site responds. The body streams back through the gateway to you.

## Pool types at a glance

| Pool            | `type` code                       | IP source            | Best for                               |
| --------------- | --------------------------------- | -------------------- | -------------------------------------- |
| **Residential** | gateway, `type-res`               | Real residential IPs | Anti-bot sites, geo-restricted content |
| **Mobile**      | gateway, `type-mob`               | 3G/4G/5G carriers    | Mobile-only content, social platforms  |
| **ISP**         | per-IP list (`ip:port:user:pass`) | Static residential   | Account farming, long-lived sessions   |

If unsure, jump to [Choose a product](/getting-started/choose-a-product.md).

## Authentication models

helodata supports two authentication models on every product:

* **User + password** — pass credentials in the `Proxy-Authorization` header or `http://user:pass@host:port` URL form. Most flexible — works from any IP. The username carries all targeting parameters (see [Username format](/getting-started/username-format.md)).
* **IP whitelist** — register your egress IPs in the dashboard and authenticate by source IP. Useful for environments that can't store credentials. Targeting is selected from the dashboard rather than the username.

See [Authentication](/api-reference/authentication.md) for full details.

## Sessions and rotation

The two credential models handle session affinity very differently.

**Gateway products (Residential, Mobile)** — sessions are opt-in via the `session` + `sesstime` segments of the username:

```
helo_s1a2b3c4d5e-type-res-region-us-session-abc123-sesstime-30
```

* `session-abc123` — any string you choose; identifies the session.
* `sesstime-30` — keep this IP for up to 30 minutes (residential cap = 30, mobile cap = 60).

Drop both segments to get a new IP on every connection (rotating mode).

**ISP proxies** — each IP in your purchased list is permanently stable. Rotation is a client-side concern: your code picks the next entry from the list. See [Client-side rotation](/products/overview-2/rotation.md).