HighVolumeException filtering Contacts

[TheJackGower]

SDK you're using (please complete the following information):

• Version 11.1.1

Describe the bug
When retrieving a filtered list of contacts using the GetContactsAsync method, the API throws a HighVolumeException (ErrorNumber: 51) even when applying a valid where clause to limit the result set. The clause used is:

where: "IsSupplier==true OR (IsSupplier==false AND IsCustomer==false)"

The organisation has over 115,000 contacts. Despite using proper filtering and paging syntax as per Xero’s documentation, the API still fails due to inefficient filtering, making it impossible to retrieve all relevant contacts.

To Reproduce
Steps to reproduce the behavior:
1 - Authenticate with an organisation with >100k contacts.
2 - Call accountingApi.GetContactsAsync with the above where clause.
3 - Do not include If-Modified-Since (i.e., attempt a full filter-based pull).
4 - Observe the HighVolumeException returned by the API.

Expected behavior
The API should successfully return a filtered list of contacts matching the given where clause, especially since the filter limits results to a subset of the full contact list.

Screenshots

Additional context

• We believe the customer to only have a couple thousand contacts that match the filter predicate.
• This creates a limitation in Xero’s API where even valid filters are considered "inefficient" at scale.

[github-actions]

PETOSS-742

[github-actions]

Thanks for raising an issue, a ticket has been created to track your request

[TheJackGower]

We've tried to avoid applying any filtering on the query and instead handle in memory.

This means looping until we reach the final page (over 1000), however we are then rate limited:

Xero.NetStandard.OAuth2.Client.ApiException: Xero API minute rate limit error calling GetContacts at Xero.NetStandard.OAuth2.Api.AccountingApi.GetContactsAsyncWithHttpInfo(String accessToken, String xeroTenantId, Nullable`1 ifModifiedSince, String where, String order, List`1 iDs, Nullable`1 page, Nullable`1 includeArchived, Nullable`1 summaryOnly, String searchTerm, Nullable`1 pageSize, CancellationToken cancellationToken) at Xero.NetStandard.OAuth2.Api.AccountingApi.GetContactsAsync(String accessToken, String xeroTenantId, Nullable`1 ifModifiedSince, String where, String order, List`1 iDs, Nullable`1 page, Nullable`1 includeArchived, Nullable`1 summaryOnly, String searchTerm, Nullable`1 pageSize, CancellationToken cancellationToken)