Using a scraper site (a site that automatically copies AO3 content) is generally against the OTW's terms of service. While they rarely go after readers, users who operate mirrors have received cease-and-desist letters.
These links are generally safe and often listed on AO3’s official social media during outages. : A verified official mirror site. ao3 mirror link
The OTW is constantly upgrading their infrastructure. In recent years, they have moved to a more resilient cloud architecture (Fastly) to mitigate DDoS attacks. As the official site becomes more stable, the demand for "AO3 mirror links" will hopefully decrease. Using a scraper site (a site that automatically
: While not a direct mirror, it is a sister archive often cited as a fallback option when AO3 is inaccessible. Troubleshooting Access : A verified official mirror site
: If a workplace or school has blocked "archiveofourown.org," an alternative extension can often slip through the filter. ⚠️ Safety & Alternatives