Number pools

A number pool is the set of phone-number channels assigned to an API key. When you omit from, Blooio picks a sender from that pool (subject to channel type, stickiness, and hybrid mode).

Non-numbered channels (RCS Business) use an alias instead of a phone pool — they still appear on the same Channels priority list.

How pools work in v4

On the Channels page, each API key has an ordered list of senders. That list is the pool:

Assignment — only senders on the key can be used for sends with that key.
Priority order — top to bottom is try order when Blooio auto-selects.
Stickiness — for Blooio numbers, ongoing conversations prefer the same sender the contact already knows.
Type filter — "channel_type": "blooio" (or twilio) narrows the pool to that channel type.

Organization
├── API key: Sales
│ ├── blooio +15551110001 ← priority 1
│ ├── blooio +15551110002
│ └── twilio +15552220001
└── API key: Support
 └── blooio +15551110003

Default send (pool auto-select)

curl -X POST https://api.blooio.com/v4/messages \
 -H "Authorization: Bearer bl_live_..." \
 -H "Content-Type: application/json" \
 -d '{
 "to": "+15551234567",
 "text": "Hello!"
 }'

Try it

Blooio walks the key's priority (or hybrid routing if enabled). The response routing object tells you which sender won.

Pin a number from the pool

{
 "from": "+15551110002",
 "to": "+15551234567",
 "text": "Hello from a specific line"
}

The number must be assigned to the API key. Otherwise the send fails with a clear ownership / not-found error.

Blooio vs Twilio in the pool

Behavior	Blooio	Twilio
Auto-select	Priority + conversation stickiness	Priority among Twilio senders on the key
Same contact again	Prefers the sticky Blooio number	Prefer pinning `from` if you need a fixed SMS brand
Rich features	iMessage (effects, polls, …)	SMS / MMS

Inbound (reply-only) numbers

Inbound-plan Blooio numbers can live in the same pool as dedicated/shared lines, but they cannot start cold conversations. They can reply once the contact (or group) has messaged that number. Mix them deliberately: outreach on a dedicated line, AI follow-up on inbound after the thread exists.

Setup checklist

Provision or import numbers (Blooio Numbers, Twilio under Integrations).
Open Channels and drag senders onto the API key that should own them.
Order the list — top is preferred for auto-select.
Optionally enable Hybrid mode when both Blooio and Twilio are on the same key.