Microsoft Project · Rate Limits

Microsoft Project Rate Limits

Microsoft Project Online APIs are hosted on SharePoint Online, so they inherit SharePoint's per-user / per-tenant throttling, plus Power Platform request limits via the Microsoft 365 license category. Limits are enforced via 429 / 503 responses with Retry-After headers; clients must honor the header. There is no published per-second cap — Microsoft uses a dynamic algorithm based on resource consumption.

Microsoft Project Rate Limits is the machine-readable rate-limit profile for Microsoft Project on the APIs.io network, conforming to the API Commons Rate Limits specification.

It captures 3 rate-limit definitions, measuring varies and requests_per_day.

The profile also includes 5 backoff/retry policies defined and response codes documented for throttled and serviceUnavailable.

Tagged areas include Rate Limiting, Project Management, Microsoft, and SharePoint.

3 Limits Throttle: 429
Rate LimitingProject ManagementMicrosoftSharePoint

Limits

SharePoint Online dynamic throttling account
varies
Dynamic per-user / per-tenant throttling based on resource consumption; no published per-second cap.
SharePoint enforces both 429 and 503 responses. Clients must read Retry-After and back off.
Power Platform requests (Microsoft 365 / Project license) account
requests_per_day · day
6000
Project Online / Plan 1 / Plan 3 fall in the Microsoft 365 + Project Online (Plan 1, 3, 5) category at 6,000 PPR per user per 24 hours.
Power Platform non-licensed pool (Power Apps / Automate, Project tenant) account
requests_per_day · day
25000
Tenant-pooled non-licensed identities (service principals, application users).

Policies

Honor Retry-After
SharePoint and Project Online responses with 429 or 503 include a Retry-After header. Wait for the indicated number of seconds before retrying. Failure to honor results in temporary blocking.
Decorate user-agent
Microsoft requires a meaningful User-Agent header (ISV|company|product/version) on CSOM and REST traffic; undecorated traffic is more aggressively throttled.
Reduce concurrency
Lower the number of parallel threads / connections from a single account before lowering the per-second rate.
Use sandbox (test) tenants
Do not load-test against production; Microsoft does not offer a higher rate for testing.
24-hour PPR window
Power Platform request entitlement is a sliding 24-hour window; limits do not roll over.

Sources