Hosted SIM numbers

SIMRelay hosts physical SIM cards in our data centers on real cellular networks. When SMS arrives at one of your numbers, we forward it to your team in seconds — but the number itself is a genuine carrier-issued SIM, not a VoIP endpoint. That distinction matters more than most teams realize.

Why real SIMs, not VoIP

VoIP numbers — the kind you get from cloud-only phone-number services — are rejected by an expanding list of platforms that care about identity verification: banks, payment processors, government services, Apple, and an unpredictable subset of any "high-trust" signup flow. Real SIMs pass these checks because they're indistinguishable from the SIM in a personal phone: they have an MSISDN tied to a real carrier, they receive SMS over the standard mobile signaling network, and they pass HLR lookups.

This is the single biggest practical difference between SIMRelay and the more familiar Twilio / Plivo / Vonage model. We're not better at providing virtual numbers — we're providing a fundamentally different kind of number.

Country coverage

We hold SIMs in multiple European countries with active inventory rotation. Country availability fluctuates with carrier supply; the current list is visible in your dashboard during signup. If you need a specific country we don't currently stock, you can join the waitlist for that country, and we'll source numbers as they become available.

Provisioning

You can claim numbers in three ways: from the shared pool (cheapest, may have prior message history), from the exclusive pool (fresh number with no history, costs more), or request a number in a country that requires sourcing (waitlist). All three flow through the same dashboard or API. Allocation typically completes within minutes for in-stock countries.

Lifecycle and recycling

Numbers stay yours for as long as your subscription stays active. When you release a number, we put it through a cooldown period before recycling it back into the pool — long enough that the next holder is unlikely to receive stray messages intended for the previous owner. Numbers can be locked to a specific user for high-stakes flows (e.g., bank account verification) so no one else on the team can intercept the SMS during that window.