> For the complete documentation index, see [llms.txt](https://docs.idlayr.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.idlayr.com/get-started/sdks/sdk-less.md).

# SDK-less

In the case of NV1.0, anything that runs on the device (IDlayr SDK, or a plain browser redirect) exists only to carry one HTTPS request over the cellular interface. That is the entire device-side footprint. It follows that:

* No SDK is technically required. A mobile browser following a redirect over cellular data is functionally equivalent to the SDK. The backend contract is identical in both cases.
* The SDK adds one important thing: control of the network interface. On a native app it forces the check over cellular even when the user is on Wi-Fi. A plain browser cannot do that, so SDK-less flows fail for users on Wi-Fi and need a fallback. So, in simple terms, the presence of our SDK increases the coverage of the NV1.0 service.
* NV2.x removes the cellular constraint by authenticating against the SIM (via the carrier's entitlement server, based on TS.43 standard) instead of the data session, which is what makes mobile web over Wi-Fi work. Today that path exists on Android; Apple does not yet support TS.43 (although that is expected to change during 2027). MNOs have a release plan for this new version, and it is different by country.

```mermaid
sequenceDiagram
    participant Br as Mobile browser (web page)
    participant CBE as Client Back end
    participant IDL as IDlayr Platform
    participant MNO as Mobile Network Operator

    Br->>CBE: Passkey ceremony complete — second factor required
    CBE->>IDL: GET /v1/eligibility/phone-numbers/{number}
    alt SNA supported AND device on cellular
        CBE->>IDL: POST /v1/number-verification/secure-sna-checks
        IDL-->>CBE: check_id + url
        CBE-->>Br: 302 → url
        Br->>MNO: follows redirects (cellular data)
        MNO-->>Br: 302 → redirect_url?code=...
        Br->>CBE: lands on redirect_url with code
        CBE->>IDL: PATCH /v1/number-verification/secure-sna-checks/{check_id} (code)
        IDL-->>CBE: match: true/false
        CBE-->>Br: payment consent proceeds in-browser
    else Wi-Fi only / no coverage / check fails
        CBE-->>Br: fallback — Reverse SMS or SMS OTP (§1.5)
    end
```


---

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