SEOmoz, a leader in SEO software, has offered link intelligence APIs for a few years (Mozscape being the latest). Although Mozscape has garnered high adoption rates (over 10 million requests/day), customer feedback uncovered shortcomings. SEOmoz now knows that 10 requests/second and a max of 50 URLs/batch "is not able to support everyone's use case." Accordingly, SEOmoz enhanced Mozscape API capabilities and is currently in beta. Although the beta is in its early stages, throughput has increased 400%.
The new enhancements include increased requests/second (i.e. increased from 10 requests/second to 200 requests/second) and larger batch sizes (expanded batch size from 50 URLs/batch to 500 URLs/batch). Although Mozscape receives hundreds of millions of requests each month, the beta is currently quite small and SEOmoz is requesting new testers for both the paid and unpaid versions.
The Mozscape API (formerly known as Linkscape), utilizes REST protocol and a JSON data format. The API provides SEO data metrics that aid developers/content creators to better understand their website (e.g. ranking potential, number of linking root domains, URL anchor texts, the number of followed/no-followed links).
SEOmoz's quality products have earned numerous awards and won significant customers, from online giants (e.g. overstock.com and Zillow) to longstanding industry icons (e.g. Home Depot and Disney). The enhancements to Mozscape is yet another step in SEOmoz's strive for excellence. Those interested in signing up for the beta can do so here.