Quick answer: A verification (OTP/pin) product is more than an endpoint that sends a code — what a buyer is really choosing is a delivery system with a fraud posture attached. Orbit's Verify API sends one-time codes over SMS, voice, WhatsApp, and email, and pairs delivery with Fraud Monitoring — including a SIM-swap risk signal checked before a code issues — so you can block, challenge, or pass with a signal instead of sending blind. Delivery, channel fallback, and fraud policy are tenant-owned settings, not a platform guarantee.
Most CPaaS shortlists treat "we have a Verify API" as a checkbox. The teams that get burned do so on the parts around the box: a code that never arrives because the channel was unavailable and there was no fallback, or a verification endpoint that happily delivered codes straight into an SMS-pumping or SIM-swap attack. This post walks the four things a buyer has to design for — the product itself, delivery across channels, the fraud-monitoring loop, and the SIM-swap signal — then gives you a tenant checklist and the questions to ask any provider, us included.
The verification product: OTP as the buyer-facing entry point
Phone verification is usually the first thing a buyer builds on a CPaaS, and the product shape is the same everywhere in outline: your server asks the verification API to send a code to a number, the user reads it back, and your server checks what they typed. What differs between providers is everything attached to that loop.
On Orbit, the product is Verify: a verification API that issues and checks one-time codes over SMS, voice, WhatsApp, and email from a single integration. The reason to run OTP through a Verify API rather than raw SMS sends is that the verification product owns the parts teams otherwise hand-roll and get wrong — code generation and expiry, attempt limits, per-channel templates, and the status of each attempt. Raw messaging APIs are the right tool for notifications you author yourself; a Verify API is the right tool for the specific "prove control of this number" flow, because the correctness of that flow is a security property, not a copy-writing exercise.
The buyer-facing question, then, is not "does the provider have OTP" — everyone does. It is "what ships with OTP": which channels, what happens when a channel can't deliver, and what the provider checks before and after it sends.
Delivery depends on channel availability — and fraud monitoring closes the loop
A one-time code is only useful if it arrives, and no single channel arrives everywhere. SMS deliverability varies by destination, sender type, and registration state; voice fails to unreachable numbers; WhatsApp requires an active session in some markets. A verification design that hardcodes one channel is a verification design with a built-in single point of failure.
The shipped answer on Orbit is two-layered. First, Verify itself is multi-channel — SMS, voice, WhatsApp, and email — so your integration can send on the channel that fits the user and fall back when it has to. Second, the Orbit Verify marketing page and the verification docs describe Verify Fraud Monitoring as the capability that watches verification traffic for abuse — the OTP-focused side of the same posture the Orbit SMS API page describes for messaging traffic generally. Fraud monitoring is what closes the loop on verification fraud: it detects abnormal verification patterns on your traffic and lets you act on them, rather than discovering the attack on next month's invoice.
That last distinction matters for a buyer. "SMS-pumping protection" on a marketing page is one checkbox; it becomes a design input only when it's wired into the verification flow you actually run — which is exactly the combination the top 10 SMS APIs comparison weighs, alongside the 10DLC registration and the SMS-pumping exposure those APIs carry. If you've read that guide, this is the next layer down: not which SMS provider to pick, but what to design for once verification is on the table.
The SIM-swap signal: a distinguishing capability, not a guarantee
The most specific fraud check worth naming is the SIM-swap risk signal. SIM swap is the attack where a fraudster convinces a carrier to move a victim's number to a new SIM; from that moment, every OTP sent to the number goes to the attacker. A verification API that checks the carrier for a recent SIM change before issuing a code catches the attack at the one moment it can still be stopped — before the code leaves. (The other half of a caller-risk decision — who is actually speaking once the call connects — is the voice-biometric leg, covered in the sibling guide voice-biometric caller verification patterns.)
Orbit's Verify product ships this as a configurable capability: when fraud monitoring is on, Verify checks for a recent SIM change before a code issues, with a tenant-set cooldown window and a policy you choose — block the send, challenge further, or pass with the signal attached for your own risk engine to weigh. Two framings to hold onto as a buyer:
- It is a signal wired into your verification decision, not a platform anti-fraud guarantee. No provider — Orbit, Twilio, Vonage, or Infobip — can promise a SIM-swap check catches every attack, because the underlying carrier data has coverage gaps and timing windows. What ships is the check plus the policy knob; the posture is yours to set.
- The distinguishing question is whether the signal is wired into the send flow at all. OTP/2FA is a commodity; a SIM-swap check consulted before a code leaves is not universal. Orbit's own Twilio and Vonage comparisons credit those providers with shipping the same combination — Verify plus a SIM-swap lookup — precisely because it is a real, checkable shipped capability on both sides, not a marketing claim either way.
When you evaluate any Verify API, this is a concrete question to ask: "Can I see the SIM-swap decision in your API, and can I set the policy (block/challenge/pass) myself, per tenant?" If the answer is a platform-wide on/off with no per-tenant posture, you are buying their default, not designing yours.
A tenant checklist: your verification posture, in four steps
Verification fraud controls on Orbit are tenant-owned — the platform gives you the levers, you set the posture for your own traffic and jurisdictions. The checklist:
- Register Verify. Turn on the verification product for your account and confirm it's live before any traffic touches it — this is a tenant-side setup step, not something that happens implicitly on first send.
- Pick channels per market. Decide which channels (SMS, voice, WhatsApp, email) serve which of your user populations, and in which order — driven by where your users are and what actually delivers there, not by what the demo defaulted to.
- Set your fraud-monitoring policy. For SIM-swap and the other signals Verify checks: choose the cooldown window, and choose what happens on a hit — block, challenge, or pass with the signal for your own systems. This is your compliance-and-risk posture; Orbit deliberately does not pick it for you.
- Handle fallback in your own flow. When a send is blocked or a channel can't deliver, decide what your product does next — fall back to another channel, fail closed, or ask the user for a different factor. The API returns the outcome; the fallback behaviour is your application logic.
Run those four and you have a verification posture that is yours — auditable, changeable, and not silently dependent on a provider's defaults.
Frequently asked questions
What is a Verify API, and how is it different from sending OTP over SMS?
A Verify API is a productized verification flow — send a code, check the code the user returns — rather than a raw message send. Raw SMS APIs deliver texts you author yourself; a Verify API owns code generation, expiry, attempt limits, and the verification state. Orbit's Verify API does this over SMS, voice, WhatsApp, and email from one integration.
Does OTP delivery really depend on channel availability?
Yes. SMS deliverability varies by destination and sender registration, voice fails to unreachable numbers, and WhatsApp has its own session rules. A multi-channel Verify API plus a fallback plan in your own application logic is the design that survives a channel being unavailable in a given market.
What is SIM swap, and what does a SIM-swap signal actually do?
SIM swap is when a fraudster gets a carrier to move your number to their SIM, so OTP codes sent to that number reach the attacker. A SIM-swap signal checks the carrier for a recent SIM change before a code issues, so the verification flow can block, challenge, or flag the send instead of delivering the code into the attack. It is a risk signal with a configurable policy, not a guarantee that every swap is caught.
Who owns the fraud-monitoring policy on Orbit — the tenant or the platform?
The tenant. Orbit treats compliance and fraud posture as tenant-owned controls: you choose whether fraud monitoring runs, the SIM-swap cooldown window, and the action on a signal (block, challenge, or pass with the signal). Orbit provides the levers and the default-open posture; the policy is yours to set for your own traffic.
How do I connect OTP strategy to the SMS API I already picked?
Start from the provider comparison — the top 10 SMS APIs in 2026 covers 10DLC registration and SMS-pumping exposure across vendors — then design the verification layer on top: channels per market, fraud-monitoring policy, and fallback behaviour. The Verify API is the piece that turns "an SMS provider that can send a code" into "a verification flow with a fraud posture."
Is phone verification with a SIM-swap signal a standard CPaaS capability?
OTP itself is universal; a SIM-swap check wired into the verification send flow is not. Twilio, Vonage, and Infobip ship the combination (a Verify product plus a SIM-swap lookup), and Orbit ships it in Verify with a per-tenant policy — a shipped, checkable capability on all sides, and a fair question to put to any provider on a shortlist.
The takeaway
A Verify API is a delivery system with a fraud posture attached, not an endpoint that sends a code. Design for the four things that actually break in production — the product fit itself, channel availability and fallback, the fraud-monitoring loop that watches your own traffic, and the SIM-swap signal checked before a code leaves — and set the posture yourself as a tenant-owned decision. If your verification flow can't answer "which channel," "what if it doesn't deliver," and "what did we check before sending," the checkbox on the shortlist hasn't done its job yet.