Magento GraphQL Custom Resolver — A Complete Walkthrough
Adobe DevDocs ships a one-page resolver tutorial that stops the moment your query needs auth, cache control, or a real service contract behind it. This post builds a customerInsights resolver from zero on Magento 2.4.4 — 2.4.9: schema.graphqls with @doc and @cache(cacheable: false), a PHP class implementing Magento\Framework\GraphQl\Query\ResolverInterface, the di.xml wiring, the bin/magento setup:upgrade schema regeneration step, and the FPC trap that silently makes your resolver return stale data on every request after deploy.