RCSB PDB · Rate Limits

Pdb Rate Limits

RCSB PDB APIs implement rate limiting to ensure fair access across all users. Static file downloads (https://files.wwpdb.org, rsync://rsync.rcsb.org) are not rate-limited. All other API services return HTTP 429 when a client exceeds the allowed request rate. RCSB PDB recommends starting at a few requests per second and adjusting based on observed 429 responses. Exact numeric ceilings are not published; clients should implement polite harvesting patterns.

Pdb Rate Limits is the machine-readable rate-limit profile for RCSB PDB on the APIs.io network, in the API Commons Rate Limits shape.

It captures 7 rate-limit definitions, measuring requests-per-second and unlimited.

Limit state is signalled in the retryAfter response header, and an exhausted limit returns HTTP 429.

This profile was written by API Evangelist and has not been verified against a page the provider published; treat every limit as unconfirmed until a dated transcription replaces it.

The profile also includes 3 backoff/retry policies defined and response codes documented for throttled.

Tagged areas include Structural Biology, Bioinformatics, Life Sciences, Open Data, and Rate Limiting.

7 Limits Exhausted: HTTP 429 retryAfter
Method: generated, dated 2026-06-13.
Written by API Evangelist on 2026-06-13 and not verified against a page the provider published. Treat every limit as unconfirmed until a dated transcription replaces it.
View Source
Structural BiologyBioinformaticsLife SciencesOpen DataRate Limiting

Limits

Data API Default client
requests-per-second
10
Recommended starting rate; actual ceiling undisclosed. Applies to https://data.rcsb.org REST and GraphQL endpoints.
Search API Default client
requests-per-second
10
Recommended starting rate; actual ceiling undisclosed. Applies to https://search.rcsb.org/rcsbsearch/v2/query.
ModelServer API Default client
requests-per-second
10
Recommended starting rate; actual ceiling undisclosed.
VolumeServer API Default client
requests-per-second
10
Recommended starting rate; actual ceiling undisclosed.
Sequence Coordinates API Default client
requests-per-second
10
Recommended starting rate; actual ceiling undisclosed.
Structure Alignment API Default client
requests-per-second
10
Asynchronous job submission; recommended starting rate undisclosed.
File Downloads (Unrestricted) client
unlimited
-1
Bulk downloads via https://files.wwpdb.org or rsync://rsync.rcsb.org are not rate-limited; polite harvesting is expected.

Policies

Backoff Strategy
Implement exponential backoff with jitter. Honor the Retry-After header when present in HTTP 429 responses before retrying.
Polite Harvesting
For large-scale or batch workloads spread requests over time and prefer off-peak hours. Consider rsync for full archive replication rather than scraping the HTTP API.
Fair Use
All APIs are freely shared infrastructure. Sustained high-volume usage that degrades service for other users may result in temporary blocks beyond documented rate limits.

Sources

Work with this as data

Every rate limit here is available over the APIs.io API and to AI agents over MCP.

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Tools for rate limits

4 MCP tools reach this
  • find_rate_limitsBrowse and filter every rate limit in the catalog.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

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This rate limit 
curl "https://apis.io/api/v1/rate-limits/pdb-rate-limits"
All rate limits 
curl "https://apis.io/api/v1/rate-limits?limit=25"

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