How does ml-connector handle Zoho Books regional base URLs?

Zoho Books customers are assigned to a single region (US, EU, India, Australia, Japan, Canada, China, or Saudi Arabia). ml-connector stores the region from the OAuth2 token response and routes all API calls to the correct regional base URL. This ensures compliance with data residency requirements and avoids cross-region latency.

What happens if a Zoho Books access token expires?

Zoho Books access tokens expire after 1 hour. ml-connector proactively refreshes the token at 55 minutes to prevent the integration from breaking mid-sync. Refresh tokens have no expiry (max 20 per user), so the connection remains valid indefinitely as long as the user does not revoke access.

Does the integration handle purchase orders and expenses?

Yes. Zoho Books purchase orders and expenses sync to BILL via the configured mappings. However, BILL v3 API does not support purchase order creation, so expenses flow into BILL's Spend and Expense workflows instead. Vendor and bill data align across both systems to keep the financial operations pipeline consistent.

Zoho BooksBILL

Zoho Books and BILL integration

Zoho Books runs your accounting across multiple regions. BILL automates Accounts Payable and Accounts Receivable workflows. Connecting them keeps your bill records in agreement and eliminates manual re-entry. Bills and expenses from Zoho Books sync into BILL automatically, vendor and contact details stay aligned, and both systems see a consistent view of your financial operations.

How Zoho Books works

Zoho Books exposes invoices, bills, purchase orders, vendor payments, customer payments, contacts, chart of accounts, journals, and expenses through REST APIs. The platform uses region-specific base URLs (US, EU, India, Australia, Japan, Canada, China, Saudi Arabia) determined by the customer's organization region. Authentication requires OAuth2 with a user-delegated refresh token (no machine-to-machine credentials flow), and every API call requires an organization ID query parameter. Access tokens expire after 1 hour. Zoho Books supports outgoing webhooks for invoices, bills, purchase orders, contacts, and payments, with HMAC signature verification and offset-based polling for list endpoints. Rate limits are 100 requests per minute with daily quotas varying by plan.

How BILL works

BILL exposes vendors, bills, payments, recurring bills, vendor credits, customers, invoices, credit memos, recurring invoices, chart of accounts, and documents through REST APIs. Authentication uses session tokens obtained via POST /v3/login (with username, password, organization ID, and development key) and is valid for 35 minutes of inactivity or 48 hours for sync token login. BILL supports outgoing webhooks for vendor lifecycle, bill lifecycle, payment updates, and invoice lifecycle events, with HMAC-SHA256 signature verification. Max 10 webhook subscriptions per organization. Spend and Expense workflows use a separate API token in the Authorization header. BILL does not support purchase orders in the v3 API.

What moves between them

Bills and expenses flow from Zoho Books into BILL. Vendor and contact records synchronize bidirectionally so both systems maintain matching supplier masters. Bill creation in Zoho Books triggers a webhook that ml-connector receives, transforms to BILL's bill schema, and posts into BILL via session token. Contact and vendor details are synced on a schedule to keep payment-processing workflows aligned. Expense records from Zoho Books can flow into BILL's Spend and Expense workflows if the customer has that module active.

How ml-connector handles it

ml-connector stores Zoho Books OAuth2 credentials and proactively refreshes access tokens at 55-minute intervals to prevent outages from the 1-hour expiry. It routes all Zoho Books API calls to the correct regional base URL (US, EU, India, Australia, Japan, Canada, China, or Saudi Arabia) using the region field from the token response. For BILL, it manages session tokens from login and stores the Spend and Expense API token separately. Zoho Books webhooks arrive at the webhook endpoint with HMAC signatures that ml-connector verifies using the configured secret. BILL webhook subscriptions (max 10 per organization) are created for bill and vendor events, and signatures are verified using HMAC-SHA256. Bill records are mapped from Zoho Books invoice and bill entities to BILL bill schema, with vendor lookup ensuring the target vendor exists in BILL before posting. Contact and vendor master data is synced bidirectionally on a schedule. Rate limits on both sides are tracked, and 429 responses trigger exponential backoff and retry. Every record carries a full audit trail and can be replayed if a downstream call fails.

A real-world example

A mid-sized e-commerce company uses Zoho Books for accounting across the US and EU operations. The UK and Ireland subsidiaries use separate Zoho Books organizations to comply with regional accounting standards. The company uses BILL for centralized Accounts Payable automation and vendor management. Before the integration, finance teams in each region exported bills from Zoho Books and manually created them in BILL, leading to duplicate work and reconciliation mismatches. With Zoho Books and BILL connected, bills created in each regional Zoho instance automatically sync to BILL under the correct organization, vendor data stays in sync across regions, and duplicate bill creation is eliminated. Month-end close becomes faster because BILL already has current vendor and bill data from Zoho Books.

What you can do

Sync bills, expenses, and purchase orders from Zoho Books to BILL, with automatic mapping to the correct vendor records.
Handle Zoho Books regional base URLs and OAuth2 token refresh so credentials never expire mid-sync.
Manage BILL session tokens and Spend and Expense API authentication so both authentication flows work seamlessly.
Verify webhook signatures on both sides and ensure bills are created in BILL only once, even if a webhook is received multiple times.
Align vendor, contact, and chart-of-accounts master data bidirectionally so payment processing workflows stay consistent.

Questions

How does ml-connector handle Zoho Books regional base URLs?: Zoho Books customers are assigned to a single region (US, EU, India, Australia, Japan, Canada, China, or Saudi Arabia). ml-connector stores the region from the OAuth2 token response and routes all API calls to the correct regional base URL. This ensures compliance with data residency requirements and avoids cross-region latency.
What happens if a Zoho Books access token expires?: Zoho Books access tokens expire after 1 hour. ml-connector proactively refreshes the token at 55 minutes to prevent the integration from breaking mid-sync. Refresh tokens have no expiry (max 20 per user), so the connection remains valid indefinitely as long as the user does not revoke access.
Does the integration handle purchase orders and expenses?: Yes. Zoho Books purchase orders and expenses sync to BILL via the configured mappings. However, BILL v3 API does not support purchase order creation, so expenses flow into BILL's Spend and Expense workflows instead. Vendor and bill data align across both systems to keep the financial operations pipeline consistent.

Connect Zoho Books and BILL

Free to use. Add your credentials, ping your real systems, and see if we fit.

Get started