Channels

Real-time pub/sub backed by Cloudflare Durable Objects. Each channel is a persistent WebSocket hub — publish from your API route, subscribe from the browser via WebSocket or SSE. Channels maintain presence state and message history automatically.

Architecture: Each unique channel name maps to a dedicated Durable Object. The DO holds connections, fans out messages, tracks presence, and keeps a sliding history window. There's no separate "create channel" step — channels are created on first access.

Publish Event

POST

/infra/channels/{channel}/publish

channels:publish0.00000045 tokens per message

Publish a single event.

curl

curl -X POST https://api.saasignal.saastemly.com/infra/channels/{channel}/publish \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{"event":"metric.updated","data":{"key":"value"}}'

json — 202 Accepted

{ "channel": "org:acme", "event_id": "evt_01JNXS...", "delivered": 3 }

typescript

await ss.infra.channels.publish('org:acme', {
  event: 'metric.updated',
  data: { mrr: 42840, delta: +1200 }
})

Open Dashboard and select your project
Go to Channels in the sidebar
Enter a channel name, event name, and JSON payload
Click Publish

The dashboard also shows a live subscriber count and message log.

Path param

Type

Description

channel required

string

Channel name (1–128 chars). Alphanumeric, hyphens, underscores, dots, colons, @.

1–128 charspattern ^[\w.:@-]+$

Body field

Type

Description

event required

string

Event name (e.g. metric.updated)

data required

any JSON

Event payload

id

string

Custom event ID for deduplication

user_id

string

Sender user ID (included in presence)

Error responses

401 Unauthorized

402 Insufficient tokens

429 Rate limited

Batch Publish

POST

/infra/channels/publish

channels:publish0.00000045 tokens per message

Publish events to one or more channels (max 50 messages per request).

curl

curl -X POST https://api.saasignal.saastemly.com/infra/channels/publish \
  -H "Authorization: Bearer sk_live_..." \
  -H "Content-Type: application/json" \
  -d '{"messages":[]}'

json — 202 Accepted

[
  { "channel": "org:acme", "event_id": "evt_01JNXS...", "delivered": 3 },
  { "channel": "org:beta", "event_id": "evt_01JNXT...", "delivered": 1 }
]

typescript

await ss.infra.channels.batchPublish([
  { channel: 'org:acme', event: 'metric.updated', data: { mrr: 42840 } },
  { channel: 'org:beta', event: 'alert', data: { level: 'warn' } },
])

Batch publish is an API-only feature
Use the REST API or TypeScript SDK for bulk publishing

You can publish to individual channels in Dashboard → Channels

Body field

Type

Description

messages required

array

Array of messages (max 50). Each: { channel, event, data, id?, user_id? }.

1–50 items

Error responses

401 Unauthorized

402 Insufficient tokens

429 Rate limited

Subscribe to Channel

GET

/infra/channels/{channel}/subscribe

channels:subscribe

Subscribe to a channel. Send Upgrade: websocket to get a WebSocket connection; otherwise you get an SSE stream (text/event-stream).

javascript

const ws = new WebSocket(
  'wss://api.saasignal.saastemly.com/infra/channels/org:acme/subscribe',
  ['Bearer', 'sk_live_...']
)

ws.onmessage = (e) => {
  const { id, event, data } = JSON.parse(e.data)
  console.log(event, data)
}

javascript

// SSE — proxy through your own API route for auth
const es = new EventSource('/api/subscribe?channel=org:acme')
es.addEventListener('metric.updated', (e) => {
  const data = JSON.parse(e.data)
  setMRR(data.mrr)
})

typescript

// Browser SDK handles auth via your /api/saasignal proxy
const channel = ss.infra.channels.subscribe('org:acme')

channel.on('metric.updated', (data) => setMRR(data.mrr))
channel.on('user.joined', (data) => addUser(data))

// Cleanup
return () => channel.close()

Open Dashboard and select your project
Go to Channels and select a channel
The channel monitor shows live messages as they arrive

You can also view presence (who's connected) and full message history.

Resume on reconnect: Store the last event ID from e.lastEventId and pass it as ?last_event_id= on reconnect. SaaSignal replays missed messages from the channel history.

Path param

Type

Description

channel required

string

Channel name (1–128 chars)

1–128 charspattern ^[\w.:@-]+$

Query param

Type

Description

last_event_id

string

Resume from this event ID. Replays missed messages (max 128 chars).

max 128 charspattern ^[\w-]+$

Error responses

401 Unauthorized

402 Insufficient tokens

429 Rate limited

Get Presence

GET

/infra/channels/{channel}/presence

channels:subscribe0.0000008 tokens per request

Get currently connected clients.

curl

curl https://api.saasignal.saastemly.com/infra/channels/{channel}/presence \
  -H "Authorization: Bearer sk_live_..."

json — 200 OK

{
  "channel": "org:acme",
  "count": 3,
  "users": [
    { "user_id": "u_123", "joined_at": "2026-03-04T12:00:00Z" },
    { "user_id": "u_456", "joined_at": "2026-03-04T12:01:30Z" }
  ]
}

typescript

const presence = await ss.infra.channels.presence('org:acme')
// presence.count, presence.users

Open Dashboard and select your project
Go to Channels and select a channel
The Presence tab shows who's currently connected

Path param

Type

Description

channel required

string

Channel name (1–128 chars)

1–128 charspattern ^[\w.:@-]+$

Error responses

401 Unauthorized

402 Insufficient tokens

429 Rate limited

Message History

GET

/infra/channels/{channel}/history

channels:subscribe0.0000008 tokens per request

Retrieve message history for a channel. Use the before parameter for backward pagination.

curl

curl https://api.saasignal.saastemly.com/infra/channels/{channel}/history \
  -H "Authorization: Bearer sk_live_..."

json — 200 OK

{ "status": "ok" }

typescript

const history = await ss.infra.channels.history('org:acme', { limit: 20 })
// history.messages

Open Dashboard and select your project
Go to Channels and select a channel
The History tab shows recent messages

Path param

Type

Description

channel required

string

Channel name (1–128 chars)

1–128 charspattern ^[\w.:@-]+$

Query param

Type

Description

limit

integer

Max messages to return. Range 1–1000, default 50.

range ≥1 .. ≤1000default 50

before

string

Return messages before this event ID (for pagination).

max 128 charspattern ^[\w-]+$

Error responses

401 Unauthorized

402 Insufficient tokens

429 Rate limited