Ordinary TSDR API calls
Published limit: 60 requests per key per minute. Plan below the ceiling to allow headroom for retries and other application traffic.
USPTO TSDR API Guide
TSDR 429 Too Many Requests: Official API Rate Limits
Understand the USPTO's published TSDR throughput limits and design reliable trademark status and document retrieval without unnecessary throttling.
TSDR case workflow
- 1Known serial number
- 2Status + document lookup
- 3Source-backed verification
Data company workflowNormalize / qualify / verify / deliver
On this page
Direct answer
What are the TSDR API rate limits?
The USPTO's TSDR FAQ publishes a general limit of 60 requests per API key per minute. PDF and ZIP downloads have a lower cap of 4 requests per API key per minute; multi-case PDF and ZIP downloads also fall under the 4-per-minute statement. Consult the official guidance for any subsequent changes before deploying a production client.
These are separate constraints. A workflow that makes only a few case-status calls can still exhaust the download allowance if it pulls too many PDFs in a short period. Likewise, batching records does not grant unlimited archive downloads.
Direct answer
What does HTTP 429 mean for the USPTO TSDR API?
An HTTP 429 Too Many Requests response indicates the service is declining a request because of request volume or an applicable throttling rule. It is an API transport response, not a trademark case status and not proof that the underlying trademark record is dead or abandoned.
The public USPTO TSDR FAQ describes a general allowance of 60 requests per API key per minute and a separate allowance of four PDF/ZIP downloads per API key per minute. Limits are subject to official change and may coexist with other restrictions. Check both usage categories before retrying.
Two quotas to design around
PDF and ZIP downloads
Published limit: 4 per key per minute, including multi-case PDF/ZIP download operations.
429 Too Many Requests
Often indicates throttling. Stop aggressive retries; inspect the response and follow any official retry guidance.
Requests by multiple workers
A shared credential means concurrent workers may consume the same allowance; coordinate their rate control.
Availability versus throttling
A 503 or a timeout may reflect service disruption, not simply a per-key limit. Diagnose the actual failure.
Recover from a TSDR 429 without bypassing quotas
Pause and classify
Stop immediate tight-loop retries; record whether the failed operation was status/XML, image, PDF or ZIP.
Inspect the response metadata
Honor a documented retry delay when provided and consider the published per-key minute window; avoid assuming every request category shares the same allowance.
Reduce concurrency
Throttle workers and limit document-download jobs independently of ordinary API requests.
Retry with bounded backoff
Apply a maximum number of retries, jitter and a circuit-breaker for persistent failures, instead of continuing indefinitely.
Validate the recovered response
Check HTTP status, content type, serial and source timestamp before writing data to downstream workflows.
Direct answer
Planning download throughput
As a planning illustration, 20 PDF downloads require at least five one-minute rate windows under a four-downloads-per-minute ceiling, assuming no other PDF/ZIP usage. This is only a theoretical lower bound: processing time, service delays, retries and other constraints can make actual completion slower.
For 120 ordinary API calls, the 60-per-minute quota similarly implies at least two rate windows if no other traffic is present. Do not equate the theoretical maximum with a guaranteed USPTO service level; add buffer and handle failures correctly.
Compliant throttling strategy
Classify each request
Track ordinary status requests separately from PDF/ZIP downloads.
Centralize rate accounting
Make sure all application workers using the same authorized credential share the correct counters.
Queue instead of bursting
Limit the number of requests sent per time window and reserve headroom below the published maximum.
Handle 429 respectfully
Back off according to documented server guidance; avoid immediate uncontrolled retries.
Use bounded retries
Retry temporary failures a limited number of times and preserve an error record for review.
Monitor production behavior
Record timestamps, endpoint classes, HTTP status and request volume without recording API key values.
More keys do not mean permission to evade limits
The published limits and the USPTO's authorization terms govern usage. Never distribute workload across credentials to evade a technical restriction or continue traffic during an official suspension. Request authorization for your intended level of access rather than attempting to circumvent restrictions.
The published limits and the USPTO's authorization terms govern usage. Never distribute workload across credentials to evade a technical restriction or continue traffic during an official suspension. Request authorization for your intended level of access rather than attempting to circumvent restrictions.
Frequently asked questions
Is the PDF limit included within 60 requests?
Plan for both the overall request controls and the separate four-per-minute PDF/ZIP rule. Consult the official gateway documentation for details.
Does a 429 mean my API key is permanently blocked?
No. A 429 generally indicates a rate-control response; confirm the returned message and key state before diagnosing a permanent restriction.
Can I use the API for monitoring?
Monitoring known records is a relevant use case when implemented within authorized usage limits.
How frequently can I check a trademark?
Frequency should be based on the business need, permitted use, quotas and actual update patterns; retrieving the same unchanged case repeatedly may add little value.
Can I guarantee maximum calls per hour?
No. Published ceilings are limits, not uptime or throughput guarantees.
Does a 429 mean the USPTO has blocked my trademark application?
No. It is an HTTP transport/rate-control response. It does not alter or describe the case's legal trademark status.
Can I use more API keys to get around the limit?
Do not use credentials to bypass official rate restrictions or an account-specific suspension. Ask the USPTO about your intended volume or lower your request rate.
Need TSDR API key access?
If you plan to retrieve public trademark case status, documents or images, review our $20-per-key offering and submit a request with your intended use. Access remains subject to USPTO service availability and usage requirements.