When Excel2Invoice connects to your Zoho Books account, it communicates through Zoho’s official API — a secure interface that allows applications to create invoices, update customer details, and send emails on your behalf.
However, like all modern cloud systems, Zoho imposes API usage limits to ensure stability, fairness, and security across all users.
Understanding these limits will help you avoid disruptions and plan your invoicing workflows efficiently.
An API limit defines how many requests (or “calls”) your connected app can make to Zoho Books within a certain time period.
Every time Excel2Invoice performs an action in Zoho — for example:
Creating or updating an invoice
Fetching customer data
Sending an invoice by email
…it counts as one or more API calls.
Zoho monitors these calls on a per-organization basis, and if the limit is exceeded, any additional requests will temporarily fail with an error like:
API limit exceeded. Please try again after some time.
The counter resets every 24 hours, usually based on your data center’s local time zone.
The limit applies per Zoho organization, not per user.
If you have multiple integrations (for example, Excel2Invoice + Zapier + a custom script), all share the same pool of API calls.
If your account exceeds the daily API quota:
Zoho Books will start rejecting new requests with error code 429: Too Many Requests.
Excel2Invoice will automatically pause invoice creation or sending until the quota resets.
Once the next 24-hour cycle begins, your connection resumes normally — no data is lost.
Excel2Invoice includes internal throttling logic to space out bulk operations and minimize the risk of hitting Zoho’s limits.
Excel2Invoice is built to work efficiently with Zoho Books’ API:
Batch processing: Groups similar actions together to reduce redundant calls.
Smart retries: Automatically retries failed requests after safe intervals.
Usage monitoring: Detects near-limit conditions and slows down sending to prevent lockouts.
Token caching: Reuses active authentication tokens instead of requesting new ones repeatedly.
These features ensure your automation stays smooth — even under high-volume operations.
Check your usage regularly
In Zoho Books:
Settings → Developer Space → API Usage
This shows how many calls you’ve made today and when the counter resets.
Avoid running multiple bulk tools at once
Running Excel2Invoice and other API-based integrations simultaneously will consume your shared quota faster.
Schedule large batches strategically
If you have thousands of invoices, run them overnight or split into smaller batches.
Upgrade your Zoho Books plan
Higher-tier plans increase daily API limits — ideal for large-volume businesses.
If you frequently reach your daily API limit or experience API-related pauses, contact:
Excel2Invoice Support: for advice on optimizing your workflow
Zoho Books Support: to confirm or extend your API quota for high-volume use cases