Visit this blog post “Understanding Web App Server Certificate Chains” that explains how certificate chains (also called chains of trust) work in HTTPS/TLS for web and application servers. A chain consists of:

* The leaf certificate (server’s own cert, proving its domain and public key),

* One or more intermediate certificates (issued by a Certificate Authority such as Let’s Encrypt or DigiCert),

* A trusted root certificate (pre-installed in browsers, OS, or JVM trust stores).

During the TLS handshake, the server sends the leaf + intermediate(s); the client verifies signatures step-by-step back to a trusted root. Browsers often auto-fetch missing intermediates, but non-browser clients (e.g., Java/Spring Boot apps, backend services) frequently fail with errors like “PKIX path building failed” or “unable to get local issuer certificate” if the full chain isn’t provided.

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