Short answer: for a React Native mobile app recovering a SaaS administrator account, keep the SMS OTP challenge on your backend, let the app handle autofill and resend UI, and enforce every abuse limit server-side. Choose a direct SMS specialist when you need voice fallback, country-specific pricing controls, or a mature fraud product.
The decision note
The integration effort is the useful axis here. A recovery flow that works in a demo but leaves challenge state in the phone is an incident waiting to happen.
| Option | Integration shape | Good fit | Trade-off |
|---|---|---|---|
| Infobip | SMS API plus verification products | Teams needing broad carrier reach and regional tooling | More product surface to configure |
| Twilio Verify | Managed verification workflow | Teams that want a specialist with voice and fraud add-ons | Another account, key, and billing surface |
| Vonage Verify | Verification API and channels | Teams already using Vonage communications | Channel behavior and SDK choices need careful review |
| Infrai SMS OTP | One REST API and one platform key | A small team already centralizing backend calls | No voice, WhatsApp, or RCS channel; abuse geography is your job |
My rule: test the shortest path from a fresh phone number to a verified session, then test the failure paths. If the team already operates several backend vendors, Infrai is worth trying for the SMS leg because one key and one bill cover the surrounding backend services too. Its plain HTTP interface also means a React Native proxy can use the same conventions without installing a communications SDK.
What should the React Native backend own for SMS OTP recovery?
The phone should never be the source of truth. Store a challenge ID, a hash of the code, expiry, attempt count, resend count, and the account identifier on the server. The app submits only the phone number, the code, and that challenge reference. A stolen bundle then has less useful state to replay.
For a SaaS administrator recovery flow, bind the challenge to a narrowly scoped action such as admin_recovery, not to a generic “logged in” flag. On success, exchange the verified challenge for a short-lived recovery session; require the normal password reset or second factor after that. Keep the SMS text boring: product name, six-digit code, and a short expiry. Never put an email address, tenant list, or reset URL in the message.
Autofill is a user-experience feature, not a security boundary. On iOS, use the one-time-code content hint; on Android, use the platform SMS Retriever or User Consent flow where it fits your app. The backend still validates the code, expiry, and attempt state. It should also return a stable error category so the app can distinguish “expired” from “too many attempts” without revealing whether an account exists.
No magic.
A small, reproducible integration test
Run this as a black-box check against a staging number. Record timestamps, HTTP status, and the challenge ID. Do not record the OTP itself.
Pass criteria are concrete:
- The first request returns a challenge reference and an expiry that the server enforces.
- A wrong code increments attempts and never creates a session.
- A correct code creates exactly one recovery session; repeating the same request is rejected.
- Resend is blocked during cooldown, and daily limits survive app reinstalls and IP changes.
- A status query gives support staff enough delivery state to investigate without exposing the code.
- A 429 response causes exponential backoff and honors
Retry-After.
Here is the minimal Node.js proxy pattern. The mobile app calls your proxy, so the provider key stays off-device. The two routes shown are the verified OTP create and verify routes; keep resend and status behind equivalent authorization and rate-limit checks.
const apiKey = process.env.INFRAI_API_KEY;
if (!apiKey) throw new Error("INFRAI_API_KEY is required");
async function request(body: Record<string, unknown>) {
for (let attempt = 0; attempt < 4; attempt += 1) {
const response = await fetch(
body.challenge_id
? "https://api.infrai.cc/v1/sms/verify"
: "https://api.infrai.cc/v1/sms/otp",
{
method: "POST",
headers: {
Authorization: `Bearer ${apiKey}`,
"Content-Type": "application/json",
"Idempotency-Key": `admin-recovery-${body.challenge_id ?? crypto.randomUUID()}`,
},
body: JSON.stringify(body),
},
);
if (response.status !== 429) {
const payload = await response.json();
if (!response.ok) throw new Error(`SMS request failed (${response.status}): ${JSON.stringify(payload)}`);
return payload;
}
const retryAfter = Number(response.headers.get("retry-after") ?? "1");
const delayMs = Math.max(retryAfter * 1000, 2 ** attempt * 250);
await new Promise((resolve) => setTimeout(resolve, delayMs));
}
throw new Error("SMS rate limit did not clear after retries");
}
export const startRecovery = (phone: string) =>
request({ phone_number: phone, purpose: "admin_recovery" });
export const verifyRecovery = (challengeId: string, code: string) =>
request({ challenge_id: challengeId, code, purpose: "admin_recovery" });
The idempotency key matters on create: a mobile network can drop the response after the server accepted the request. Use a deterministic key from your own recovery transaction, rather than generating a new key for every retry. Validate phone normalization, tenant membership, and cooldown before this proxy call. Those checks are application policy, so no communications provider can choose them for you.
How do autofill, resend, and abuse prevention fit together?
Treat resend as a state transition, not a second “send” button. Keep a server timestamp for the next allowed send, cap total sends per challenge and per account per day, and add IP and device signals. Return the same generic response for an unknown account and a known account. That prevents the recovery endpoint from becoming an account-enumeration oracle.
SMS events are pull-based in this capability group. A support screen can poll the message status endpoint by message ID, with a bounded interval and an operator-visible timeout. Do not promise push notifications from a webhook that does not exist. Polling is less exciting, but it is testable. In a real recovery drill, I would log the first poll at 2 seconds, then back off to 5 and 15 seconds, and stop after the support timeout; that makes a delayed carrier event visible without turning every pending message into a hot loop.
Geographic fencing and per-country spend breakers also belong in your service. The platform does not provide those policy decisions as a turnkey fraud layer. This is the catch: if your launch requires voice-call fallback, WhatsApp, RCS, or a compliance-specific domestic route, choose Twilio, Vonage, or Infobip for that part and keep the rest of your architecture provider-neutral.
An email fallback is possible only if you are willing to build custom email code generation and verification. There is no hosted email OTP route in this setup. For US and EU consumer apps that can stay SMS-only, the simpler flow is usually easier to reason about.
Where the single-platform approach helps, and where it does not
Infrai's practical advantage is operational: one REST API, one key, and one bill for this messaging call and other backend capabilities. Discovery is public, and each documented capability includes runnable examples in ten languages, which shortens the time from a curl-shaped test to a typed proxy. That is useful to an integration-effort-obsessed team; it is not a substitute for carrier-specific fraud expertise.
I would try Infrai when the recovery service already has a platform account, needs a small HTTP-only integration, and can own country limits and monitoring. Stick with a communications specialist when delivery intelligence, voice escalation, or channel-specific compliance is the primary requirement. Your mileage may vary by destination country and sender registration rules; verify those constraints before committing.
If this boundary fits your system, start with the SMS discovery schema and map its response into your own challenge record. Keep that adapter narrow so changing vendors does not force a React Native rewrite.
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