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Third-party dependencies expose websites to shared risks and cascading failures. The dependencies impact African websites as well e.g., Afrihost outage in 2022 [15]. While the prevalence of third-party dependencies has been studied for globally popular websites, Africa is largely underrepresented in those studies. Hence, this work analyzes the prevalence of third-party infrastructure dependencies in Africa-centric websites from 4 African vantage points. We consider websites that fall into one of the four categories: Africa-visited (popular in Africa) Africa-hosted (sites hosted in Africa), Africa-dominant (sites targeted towards users in Africa), and Africa-operated (websites operated in Africa). Our key findings are: 1) 93% of the Africa-visited websites critically depend on a third-party DNS, CDN, or CA. In perspective, US-visited websites are up to 25% less critically dependent. 2) 97% of Africa-dominant, 96% of Africa-hosted, and 95% of Africa-operated websites are critically dependent on a third-party DNS, CDN, or CA provider. 3) The use of third-party services is concentrated where only 3 providers can affect 60% of the Africa-centric websites. Our findings have key implications for the present usage and recommendations for the future evolution of the Internet in Africa. 

Many websites rely on third parties for services (e.g., DNS, CDN, etc.). However, it also exposes them to shared risks from attacks (e.g., Mirai DDoS attack [24]) or cascading failures (e.g., GlobalSign revocation error [21]). Motivated by such incidents, we analyze the prevalence and impact of third-party dependencies, focusing on three critical infrastructure services: DNS, CDN, and certificate revocation checking by CA. We analyze both direct (e.g., Twitter uses Dyn) and indirect (e.g., Netflix uses Symantec as CA which uses Verisign for DNS) dependencies. We also take two snapshots in 2016 and 2020 to understand how the dependencies evolved. Our key findings are: (1) 89% of the Alexa top-100K websites critically depend on third-party DNS, CDN, or CA providers i.e., if these providers go down, these websites could suffer service disruption; (2) the use of third-party services is concentrated, and the top-3 providers of CDN, DNS, or CA services can affect 50%-70% of the top-100K websites; (3) indirect dependencies amplify the impact of popular CDN and DNS providers by up to 25X; and (4) some third-party dependencies and concentration increased marginally between 2016 to 2020. Based on our findings, we derive key impli- cations for different stakeholders in the web ecosystem.