Stellar Development Foundation's validator nodes and public Horizon API temporarily went offline for 10+ hours on April 6, 2021, but the decentralized Stellar network remained operational and continued processing transactions throughout the incident.

The Stellar Development Foundation's validator nodes and public Horizon API instance went down around 1:00 am PDT on April 6, 2021, and were restored at 11:28 am PDT. Despite this outage, the Stellar network itself remained online and continued processing transactions because the network is decentralized and other validator nodes kept functioning. Users running their own Horizon instances were unaffected. SDF's engineering team quickly brought new nodes and a Horizon instance online, though investigation into the root cause continued. The incident demonstrated how Stellar's decentralized architecture ensures network resilience even when major infrastructure components fail.