How to Integrate Zoho Books with V0

Zoho Books requires OAuth2 authentication, which involves a one-time setup to obtain a refresh token. This setup is done before writing any Next.js code. First, go to api-console.zoho.com and click 'Add Client'. Select 'Server-based Applications' as the client type — this is appropriate for Next.js server-side API routes. Enter a redirect URI (use http://localhost:3000/auth/callback for initial setup, you can update it to your Vercel URL later). Note the Client ID and Client Secret. Next, generate the authorization URL: visit https://accounts.zoho.com/oauth/v2/auth?scope=ZohoBooks.fullaccess.all&client_id=YOUR_CLIENT_ID&response_type=code&redirect_uri=http://localhost:3000/auth/callback&access_type=offline. Open this URL in your browser, authorize your Zoho Books account, and you will be redirected to your redirect URI with a code parameter in the URL (e.g., http://localhost:3000/auth/callback?code=1000.abc123). Copy this authorization code. Then exchange it for a refresh token by making a POST request to https://accounts.zoho.com/oauth/v2/token with parameters: client_id, client_secret, code (the authorization code), redirect_uri, and grant_type=authorization_code. You can do this with curl or Postman. The response includes a refresh_token — copy and store it securely. This refresh_token is what you will store in Vercel and use in your API routes to obtain access tokens. Your Zoho Books Organization ID is found in Zoho Books → Settings → Organization Profile at the bottom of the page.

1# One-time curl command to exchange authorization code for refresh token:
2# Replace YOUR_CLIENT_ID, YOUR_CLIENT_SECRET, YOUR_AUTH_CODE
3curl -X POST 'https://accounts.zoho.com/oauth/v2/token' \
4  -d 'client_id=YOUR_CLIENT_ID' \
5  -d 'client_secret=YOUR_CLIENT_SECRET' \
6  -d 'code=YOUR_AUTH_CODE' \
7  -d 'redirect_uri=http://localhost:3000/auth/callback' \
8  -d 'grant_type=authorization_code'
9
10# Response includes:
11# { "access_token": "...", "refresh_token": "1000.xxx...", "expires_in": 3600 }
12# Save the refresh_token — this is the long-lived credential for your app

Open V0 at v0.dev and describe the accounting or invoicing interface you want to build. Financial dashboards require careful data presentation — currency formatting, status badge colors, date formatting, and data tables with sorting. Be specific about number formatting (use '$1,234.56' format with thousands separator), status colors (paid = green, overdue = red, draft = gray, sent = blue), and the date format you want (full date vs relative like '3 days ago'). For an invoice management dashboard, describe the key metrics at the top (outstanding amount, overdue amount, paid this month), the invoice table with sortable columns, and the invoice detail view when a row is clicked. For an expense tracker, describe the mobile-first form with receipt upload area, category selector, and submission confirmation. Include skeleton loading states and empty states (when no invoices exist yet) in your prompt. V0 generates financial dashboard layouts well when you describe them with specific field names matching the actual data structure — mention field names like invoice_number, customer_name, total, due_date, and status directly in your prompt so V0 generates the correct component props and data bindings. After generating, push to GitHub using V0's Git panel.

Create the Next.js API routes that authenticate with Zoho's OAuth2 token endpoint and then call the Zoho Books API. The key pattern is a helper function that exchanges your stored refresh token for a short-lived access token, then uses that access token for the actual Zoho Books API call. Access tokens expire in 1 hour — do not store them; instead, generate a fresh one at the start of each API route invocation. The Zoho Books API base URL is https://www.zohoapis.com/books/v3 and all requests require the Authorization: Zoho-oauthtoken ACCESS_TOKEN header and the organization_id query parameter (your Zoho Books organization ID). The invoices endpoint is GET /invoices and supports filters for status, customer_id, date range, and pagination via page and per_page. The response includes an invoices array and pagination metadata. For creating invoices, POST to /invoices with a JSON body containing customer_id, invoice_date, due_date, and a line_items array. Each line item needs name, quantity, rate, and optionally account_id and tax_id. Zoho Books uses different API domains depending on your account's data region — accounts.zoho.com for authentication and www.zohoapis.com for the Books API work for US accounts. European accounts may need eu.zohoapis.com and Indian accounts in.zohoapis.com — check your Zoho account's region in Zoho Books URL.

1// app/api/zoho-books/invoices/route.ts
2import { NextRequest, NextResponse } from 'next/server';
3
4const ZOHO_TOKEN_URL = 'https://accounts.zoho.com/oauth/v2/token';
5const ZOHO_BOOKS_BASE = 'https://www.zohoapis.com/books/v3';
6
7async function getZohoAccessToken(): Promise<string> {
8  const response = await fetch(ZOHO_TOKEN_URL, {
9    method: 'POST',
10    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
11    body: new URLSearchParams({
12      client_id: process.env.ZOHO_CLIENT_ID!,
13      client_secret: process.env.ZOHO_CLIENT_SECRET!,
14      refresh_token: process.env.ZOHO_REFRESH_TOKEN!,
15      grant_type: 'refresh_token',
16    }),
17  });
18
19  if (!response.ok) {
20    throw new Error(`Failed to get Zoho access token: ${response.status}`);
21  }
22
23  const data = await response.json();
24  if (data.error) {
25    throw new Error(`Zoho OAuth error: ${data.error}`);
26  }
27
28  return data.access_token as string;
29}
30
31export async function GET(request: NextRequest) {
32  const orgId = process.env.ZOHO_BOOKS_ORG_ID;
33
34  if (!process.env.ZOHO_CLIENT_ID || !process.env.ZOHO_REFRESH_TOKEN || !orgId) {
35    return NextResponse.json(
36      { error: 'Zoho Books is not configured' },
37      { status: 500 }
38    );
39  }
40
41  const { searchParams } = new URL(request.url);
42  const status = searchParams.get('status') ?? 'all'; // draft, sent, overdue, paid
43  const page = searchParams.get('page') ?? '1';
44
45  try {
46    const accessToken = await getZohoAccessToken();
47
48    const params = new URLSearchParams({
49      organization_id: orgId,
50      page,
51      per_page: '25',
52    });
53
54    if (status !== 'all') {
55      params.set('status', status);
56    }
57
58    const response = await fetch(
59      `${ZOHO_BOOKS_BASE}/invoices?${params.toString()}`,
60      {
61        headers: {
62          Authorization: `Zoho-oauthtoken ${accessToken}`,
63          'Content-Type': 'application/json',
64        },
65      }
66    );
67
68    if (!response.ok) {
69      const error = await response.json();
70      return NextResponse.json(
71        { error: 'Zoho Books API error', details: error.message },
72        { status: response.status }
73      );
74    }
75
76    const data = await response.json();
77    return NextResponse.json({
78      invoices: data.invoices ?? [],
79      pageContext: data.page_context ?? {},
80    });
81  } catch (error) {
82    const message = error instanceof Error ? error.message : 'Unknown error';
83    console.error('Zoho Books invoices fetch failed:', message);
84    return NextResponse.json(
85      { error: 'Failed to fetch invoices', details: message },
86      { status: 500 }
87    );
88  }
89}

Push your code to GitHub and configure all four Zoho Books credentials in Vercel. Open the Vercel Dashboard, select your project, and navigate to Settings → Environment Variables. Add ZOHO_CLIENT_ID (your OAuth client ID from api-console.zoho.com), ZOHO_CLIENT_SECRET (the client secret from the same page), ZOHO_REFRESH_TOKEN (the long-lived refresh token obtained in Step 1), and ZOHO_BOOKS_ORG_ID (your organization ID from Zoho Books → Settings → Organization Profile). None of these variables should have the NEXT_PUBLIC_ prefix — all four are server-side secrets. Set all variables for Production, Preview, and Development environments. Click Save and trigger a redeployment. After deployment, open your dashboard and verify that real Zoho Books invoices appear in the table. If invoices do not load, check Vercel function logs for the specific error — common issues are using the wrong Zoho data region URL, an expired or incorrectly copied refresh token, or an incorrect organization ID. For European accounts, update ZOHO_BOOKS_BASE in your code to https://eu.zohoapis.com/books/v3 and ZOHO_TOKEN_URL to https://accounts.zoho.eu/oauth/v2/token.