Valve does not publish a precise per-second cap on Steam Web API calls in the public Steamworks docs. The widely documented behavior, confirmed by the Steam Web API Terms of Use, is a soft daily quota of approximately 100,000 calls per Web API key, and a per-IP burst limit that returns HTTP 429 (or HTTP 403 for repeated abuse) once exceeded. Some interfaces (ISteamUser/GetPlayerSummaries) accept up to 100 SteamIDs per request — clients should batch to reduce call volume. The unofficial Storefront API (store.steampowered.com/api/) is more aggressively rate-limited and returns 429 well below the Web API quota. Partner microtransaction interfaces are not subject to the same key-level quota; per the Steamworks documentation they are governed by the per-product Steamworks agreement.
Soft daily quota per Web API key as referenced by community documentation and Valve's Web API Terms. Excessive use can result in temporary 429 or 403 responses.
Steam Web API Burst (per IP) ip
requests-per-second · second
-1
Undocumented per-IP burst limit. Sustained high concurrency from a single IP returns 429.
Storefront API ip
requests-per-second · second
1
Unofficial https://store.steampowered.com/api/* endpoints — common safe ceiling is approximately 1 request/second from a single IP; exceeding triggers 429 quickly.
GetPlayerSummaries Batch Size request
steamids · per-request
100
ISteamUser/GetPlayerSummaries v0002 accepts up to 100 SteamIDs per call — batch lookups to reduce request volume.
Web API Key Quantity account
api-keys · simultaneous
1
Each Steam account can hold one active Web API key; key rotation invalidates the previous key.
Policies
Backoff Strategy
Implement exponential backoff with jitter on 429 / 403 responses; throttle to well below observed throughput before retrying.
Batch and Cache
Batch Steam ID lookups (up to 100 per request); cache catalog/news/schema responses for hours/days as Valve data changes infrequently.
Use Web API not Storefront
Where the same data is available via Web API and Storefront, prefer the Web API — it has a more permissive quota and is supported.
Respect Terms of Use
The Steam Web API Terms of Use prohibit reselling Web API data and require attribution. Long-term commercial scraping of the Storefront API risks key revocation.