Sender Pools
A sender pool is a named group offrom addresses (E.164 numbers, short codes, or alphanumeric sender IDs) that Orbit picks from automatically at send time, instead of you hardcoding a single number on every send. Pools exist to solve two problems: spreading volume across more than one number so no single number gets overloaded or over-flagged by carriers, and picking a local number for a recipient so your messages don’t arrive from an obviously foreign long code.
For the full request/response schema, see the Sender Pools API reference.
When to use a pool
- High-volume sending — spread messages across several numbers so throughput and carrier reputation aren’t concentrated on one sender.
- Conversation continuity — a support or marketing thread should always reply from the same number the contact already has in their inbox (
sticky). - Local presence — a recipient in France should see a French number, a recipient in Brazil a Brazilian one (
geomatch). - Deliverability rotation — swap out numbers whose reputation has degraded without changing anything in your send code.
Creating a pool
sender_dids accepts a mix of E.164 long codes, numeric short codes, and alphanumeric sender IDs in the same pool — useful if you operate in a market that requires an alphanumeric sender ID as a fallback alongside long codes. Up to 50 entries per pool, no duplicates.
Selection strategies
Pick
sticky for anything conversational (support, two-way SMS), geomatch for international campaigns where local presence matters, and round_robin or random for pure volume distribution with no continuity requirement.
Previewing a selection
Before you route real traffic through a pool, preview which sender a given recipient would get — without committing any selection state (a preview never advances a round-robin counter or writes a sticky assignment):422 SENDER_POOL_EMPTY — add at least one DID before previewing or sending through it.
Deliverability health
Each sender in a pool accumulates a health score from delivery outcomes.GET /messaging/sender-pools/{id}/health returns the per-member tier so you can see which senders are degraded before they cause delivery problems — the same signal Orbit’s rotation scheduler uses to auto-swap a degraded sender for a warmed replacement.
Endpoints
See also
- Messaging credentials & services — attaching a pool as a messaging service’s sending identity
- SMPP — an alternative way to submit the sends a pool routes