> For the complete documentation index, see [llms.txt](https://docs.tumbler.app/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.tumbler.app/features/overview.md).

# Overview and matrix

## Who this is for

Providers planning which features to enable in their subscriptions and how to declare them.

## What you can do

* See what is free and what belongs to **\[PAID]** Advanced Connection Control (ACC).
* Understand which metadata/flags are required for each feature.
* Compare backend behavior when a paid feature is not activated.

## Examples

* Declaring `capabilities` in a subscription response.
* Status matrix below with **\[PAID]** marks.
* Related settings in limits and balancing sections.

## See also

* [basic-limits.md](/features/basic-limits.md)
* [advanced-connection-control.md](/features/advanced-connection-control.md)
* [balancing.md](/features/balancing.md)

## Feature matrix

| Feature                             | Status                                  | How to declare                                                                                       | If payment is not active                                                                                 |
| ----------------------------------- | --------------------------------------- | ---------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| Subscription delivery (all formats) | Free                                    | Any supported body format: text VLESS, base64, JSON links/nodes, best-effort Xray/sing-box outbounds | Works out of the box                                                                                     |
| Support / Manage / Hide Settings    | Free                                    | Metadata or headers `support-url`, `manage-url`, `hide-settings`                                     | Applied as declared                                                                                      |
| Quota / Expiry in UI                | Free                                    | `subscription-userinfo` or fields `upload`, `download`, `total`, `expire` (`expire-at`)              | Applied as declared                                                                                      |
| Mirrors / New URL / New Domain      | Free                                    | `mirrors`, `new-url`, `new-domain` in meta or headers                                                | Applied as declared                                                                                      |
| `balancer-method`                   | Free                                    | \`meta\["balancer-method"]="ping"                                                                    | "connections"\`                                                                                          |
| `connection-limit = 0` (unlimited)  | Free                                    | `meta["connection-limit"]=0`                                                                         | No restrictions                                                                                          |
| `connection-limit = 1`              | Free                                    | `meta["connection-limit"]=1`                                                                         | Limits to one connection                                                                                 |
| `connection-limit >= 2`             | **\[PAID]** Advanced Connection Control | `meta.connection-limit=N` + `meta.capabilities=["advanced_connection_control"]`                      | If ACC is not active, the value is automatically reduced to `1` (backend limits to 1 and logs a warning) |
| Per-config / per-group limits       | **\[PAID]** ACC                         | ACC-specific fields agreed separately                                                                | Ignored; basic limits remain                                                                             |
| Soft/hard enforcement modes         | **\[PAID]** ACC                         | ACC policies                                                                                         | Ignored; basic behavior remains                                                                          |
| Callbacks                           | **\[PAID]** ACC                         | ACC callback fields                                                                                  | Ignored                                                                                                  |
| Device priorities                   | **\[PAID]** ACC                         | ACC fields for device prioritization                                                                 | Ignored                                                                                                  |

## Behavior without ACC activation

* The only special exception: if `connection-limit >= 2` is set without ACC entitlement, the value is automatically reduced to `1` with a warning in logs, so access is not blocked for all users.
* Any other ACC fields (callbacks, priorities, additional limits, soft/hard modes) are ignored, and free baseline behavior remains.
* To enable paid features, add `advanced_connection_control` to the `meta.capabilities` array and make sure the plan allows it.

## Declaration rules

* List all features in `meta.capabilities` as an array of strings. In text subscriptions, use the meta line `#capabilities: advanced_connection_control`.
* Describe policies and parameters for each feature in the corresponding sections, without changing public keys.
* If a feature is temporarily unavailable, remove it from `meta.capabilities` and update the subscription body/`ETag`.

## Compatibility

Adding new flags must be optional for existing clients. Always record changes in [changelog.md](/changelog.md) with the effective date.


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