Major livestream event pricing example
This example shows pricing for a 1-hour livestream chat with 5,000 active users. It uses Ably’s per-message and per-minute billing model, and demonstrates how server-side batching reduces message volume and overall cost in high-traffic rooms.
Scenario
- Event duration: 1 hour
- Users in chat: 5,000
- Per user: 5 chat messages, 2 reactions
Total cost: $94.50
Cost breakdown
The following breakdown shows the cost of connections, channels and messages in this scenario.
How messages are counted
Every chat message and reaction counts as a billable message. Messages are counted when they're sent to Ably and when they're delivered to users. Usage is billed in increments of one million messages, rounded up.
One message sent to a room with 5,000 subscribers = 5,001 messages (the sender of the message also receives it).
Messages generated by this scenario
| Message type | Calculation | Messages |
|---|---|---|
| Messages sent | 5,000 × (5 messages + 2 reactions per user) | 35,000 |
| Messages delivered | 35,000 messages × 5,000 users | 175,000,000 |
| Total messages | 35,000 sent messages + 175,000,000 delivered messages | 175,035,000 |
Without batching cost
| Total messages | Messages Calculation | Cost calculation | Total cost |
|---|---|---|---|
| 175,035,000 | As above | 176,000,000 × $2.50/M messages | $440.00 |
Reduce message costs with server-side batching
With Ably's server-side batching, messages published within a short window (for example 500ms) are grouped and delivered together. With a 500ms window, that's 7,200 batches per hour, with each batch being charged as one billable message.
This reduces the number of published messages which is the main cost driver in large rooms. In this scenario, batching reduces the total billed message volume by 79%.
With batching messages
| Delivery method | Calculation | Total messages |
|---|---|---|
| Messages sent | 35,000 messages × 1 | 35,000 |
| Messages delivered | 7,200 batches × 5,000 | 36,000,000 |
| Total messages | 35,000 sent messages + 36,000,000 delivered messages | 36,035,000 |
With batching cost
| Total messages | Messages Calculation | Cost calculation | Total cost |
|---|---|---|---|
| 36,035,000 | As above | 37,000,000 × $2.50/M messages | $92.50 |
How connection and channel minutes are counted
Both connection minutes and channel minutes are rounded up per million minutes used.
Connection minutes:
Connection minutes are billed based on how long a user remains connected to Ably for.
| Item | Calculation | Total |
|---|---|---|
| Connection minutes | 5,000 participants × 60 mins | 300,000 mins |
| Cost | 1,000,000 mins × $1.00/M | $1.00 |
Channel minutes:
Channel minutes are billed based on how long channels are active for. Traffic is all over a single channel in this scenario.
| Item | Calculation | Total |
|---|---|---|
| Channel minutes | 1 room × 60 mins | 60 mins |
| Cost | 1,000,000 mins × $1.00/M | $1.00 |
Total cost
The total cost of this livestream.
| Item | Cost |
|---|---|
| Messages | $92.50 |
| Connection minutes | $1.00 |
| Channel minutes | $1.00 |
| Total | $94.50 |