Backend (Next.js App Router)

import { NextResponse } from "next/server";

type TypeOfSessionRequest = {
  borrowerProviderID: string;
  contactNumber: string;
  pan?: string | null;
};

type TypeOfPlatformSessionResponse = {
  embedUrl: string;
  sessionToken: string;
  sessionExpiresAt: string;
  bootstrapExpiresAt: string;
  borrowerProviderID: string;
  borrowerID: string;
  environment: "TEST" | "LIVE";
};

export async function POST(request: Request) {
  try {
    const payload = (await request
      .json()
      .catch(() => null)) as TypeOfSessionRequest | null;
    const borrowerProviderID = payload?.borrowerProviderID?.trim();
    const contactNumber = payload?.contactNumber?.trim();
    const pan = payload?.pan?.trim();

    if (!borrowerProviderID) {
      return NextResponse.json(
        { error: "Missing borrowerProviderID." },
        { status: 400 },
      );
    }
    if (!contactNumber) {
      return NextResponse.json(
        { error: "Missing contactNumber." },
        { status: 400 },
      );
    }

    const platformBaseURL = process.env.PLATFORM_BASE_URL;
    const platformAPIKey = process.env.PLATFORM_API_KEY;

    if (!platformBaseURL || !platformAPIKey) {
      return NextResponse.json(
        { error: "Platform configuration missing." },
        { status: 500 },
      );
    }

    const response = await fetch(`${platformBaseURL}/api/lab/sessions`, {
      method: "POST",
      headers: {
        Authorization: `Bearer ${platformAPIKey}`,
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        borrowerProviderID,
        contactNumber,
        ...(pan ? { pan } : {}),
      }),
      cache: "no-store",
    });

    if (!response.ok) {
      const errorPayload = await response.json().catch(() => ({}));
      return NextResponse.json(
        { error: "Platform session failed.", details: errorPayload },
        { status: response.status },
      );
    }

    const platformSession =
      (await response.json()) as TypeOfPlatformSessionResponse;

    // Return only what the frontend needs.
    return NextResponse.json({
      embedUrl: platformSession.embedUrl,
    });
  } catch (error) {
    return NextResponse.json({ error: "Unexpected error." }, { status: 500 });
  }
}

PLATFORM_BASE_URL="https://your-platform-domain.com" # This shall be provided by Aarthik Labs
PLATFORM_API_KEY="sk_live_xxx" # keep on server only