Chronicling America vs ModelPartFinder Error Codes

Same instrument, two spec sheets — measured, not claimed.

Uptime · 30d
Uptime · 90d—%—%
Uptime · 30d—%—%
P50 · ms
P95 · ms
Authnonenone
CORSnoyes
HTTPSyesyes
Card requirednono
Commercial useyesunclear
Data licensePublic domain / no known copyright (Library of Congress)Unverified
Free tierFree — public-domain collection dataFree — no key
Rate limitLoC throttles heavy crawling (see LoC API policy)Unpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Chronicling America vs ModelPartFinder Error Codes: common questions

Which is more reliable, Chronicling America or ModelPartFinder Error Codes?

On our scheduled checks, ModelPartFinder Error Codes leads on measured uptime — Chronicling America at —% versus ModelPartFinder Error Codes at —% over 90 days. These are our own probe results, not provider claims; the uptime bars above show the day-by-day record for both.

Do Chronicling America and ModelPartFinder Error Codes need an API key?

Neither needs a paid key — Chronicling America is callable with no signup, and ModelPartFinder Error Codes is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Chronicling America and ModelPartFinder Error Codes from the browser?

Only ModelPartFinder Error Codes is browser-friendly — it returns CORS headers over HTTPS. Chronicling America needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are Chronicling America and ModelPartFinder Error Codes free for commercial use?

Chronicling America allows commercial use on its free tier, and ModelPartFinder Error Codes has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.