Convex, the application backend startup founded by former Dropbox infrastructure engineers, has closed a $57 million Series B led by Insight Partners, the company announced on August 4, 2026. Etna Labs, Spark Capital, Andreessen Horowitz, and Justin Kan joined the round, which follows the company’s $26 million Series A in 2022. The round lands on a usage claim the company is eager to put in front of investors: millions of Convex instances now run in production. Over the past year Convex…