# Spaces pricing

How Spaces SDK features contribute to your message count and strategies to optimize costs.

The [Spaces SDK](https://ably.com/docs/spaces.md) is built on top of [Pub/Sub](https://ably.com/docs/pub-sub.md) channels and [presence](https://ably.com/docs/presence-occupancy/presence.md). All Spaces operations generate Pub/Sub messages that follow the same counting rules.

## Spaces operations 

The following table shows how Spaces operations contribute to your message count:

| Operation | Messages counted |
| --- | --- |
| [Members](https://ably.com/docs/spaces/space.md) ||
| Enter space | 1 inbound message |
| Leave space | 1 inbound message |
| Update profile | 1 inbound message |
| Space event delivery | 1 outbound message per subscriber |
| [Locations](https://ably.com/docs/spaces/locations.md) ||
| Set location | 1 inbound message |
| Location event delivery | 1 outbound message per subscriber |
| [Cursors](https://ably.com/docs/spaces/cursors.md) ||
| Set cursor position | 1 inbound message per batch (default batch interval 25ms) |
| Cursor event delivery | 1 outbound message per subscriber |
| [Locking](https://ably.com/docs/spaces/locking.md) ||
| Acquire lock | 1 inbound message |
| Release lock | 1 inbound message |
| Lock event delivery | 1 outbound message per subscriber |

Registering multiple subscription listeners for the same event does not increase your message count. These are [client-side filtered events](https://ably.com/docs/spaces/space.md#subscribe) where only a single message is published per event by Ably.

## Channels 

Each space maps to an underlying Pub/Sub [channel](https://ably.com/docs/channels.md). Live cursors use a [separate channel](https://ably.com/docs/spaces/cursors.md#foundations) from other space features due to their high update frequency. Both channels contribute to your [channel count](https://ably.com/docs/platform/pricing.md#channels).

## Connections 

Ably bills each connected client for [connection minutes](https://ably.com/docs/platform/pricing.md#connections). A connection-minute is counted for every minute a client maintains an open connection, regardless of activity. Clients that remain connected but idle still accrue connection minutes.

## Cost optimization 

### Increase cursor batch interval

Increase the [`outboundBatchInterval`](https://ably.com/docs/spaces/cursors.md#batch) to reduce the frequency of cursor position updates. The default is 25ms. Increasing this value reduces the number of messages at the cost of less smooth cursor movement.

### Limit concurrent cursor streaming

Ably recommends a maximum of [20 members](https://ably.com/docs/spaces/cursors.md) simultaneously streaming their cursors in a space for an optimal end-user experience. Beyond this, the volume of cursor messages increases significantly.

### Use occupancy instead of presence for large spaces

For spaces with many members where you only need a count of active users, use [occupancy](https://ably.com/docs/presence-occupancy/occupancy.md) on the underlying channel instead of tracking individual presence events.

## Documentation Index

To discover additional Ably documentation:

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2. Identify relevant URLs from that index.
3. Fetch target pages as needed.

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