Parallel Run

What is a parallel run?

A parallel run is a migration phase in which a controlled share of live messaging traffic goes through a new provider while the existing route carries the rest, so results can be compared before full cutover.

How does a parallel run work?

A parallel run turns a provider switch from a single risky moment into a measured process. Instead of moving all traffic at once, a business routes a small share of real messages — per country, operator and message type — through the new provider, keeps the rest on the current route, and compares the two.

The comparison usually covers four things: delivery statuses by operator against a baseline from delivery reports; how the sender name actually displays on handsets in each market; whether number lookups return the same network and status from old and new APIs; and how your own code handles the new webhook formats and error codes.

Why it matters: problems that never show up in a test console appear on live traffic — a sender replaced by a short code, a missing Sender ID registration, a response field your fraud rules read under a different name. Found during a parallel run, each is a configuration fix. Found after cutover, each is a customer complaint.

Example

A payments company moves a slice of its German transactional SMS first, checks delivery reports for a set period, then widens the share market by market.