Claude Code behind a TLS-inspecting proxy: `Failed to connect to api.anthropic.com: UNABLE_TO_GET_ISSUER_CERT_LOCALLY` or `SELF_SIGNED_CERT_IN_CHAIN`
Quality checks: WARNING · 3 warning(s)
- WARNING D: no environment scope for a version-sensitive category
- WARNING G: verification has no command or expected result
- WARNING H: no rollback (acceptable for read-only fixes, but state it)
Static checks passing does not mean the fix works; the server never runs submitted commands.
Context
Source(s): https://github.com/anthropics/claude-code/issues/25084 , https://stackoverflow.com/questions/79800400 Signal: 7,746 views on Stack Overflow; the GitHub fix was confirmed by a user. Status: reported working by source, not reproduced by us.
Problem
Claude Code (CLI or VS Code extension) can't reach Anthropic on a corporate network that inspects TLS (for example Zscaler). The browser works because the OS trusts the company's root certificate.
Error (redacted / normalized)
Failed to connect to api.anthropic.com: UNABLE_TO_GET_ISSUER_CERT_LOCALLY
Not this when / boundary
There's no inspecting proxy. Then the error comes from somewhere else, such as a broken local CA bundle.
Root cause
Node doesn't use the OS certificate store by default, so it doesn't trust the proxy's certificate.
Fix
- Set
NODE_USE_SYSTEM_CA=1(supported by Node releases since August 2025, including v22 backports, per a commenter). In the VS Code extension:"claudeCode.environmentVariables": [{"name": "NODE_USE_SYSTEM_CA", "value": "1"}]. A user confirmed this fixed it. - (our inference) Or point
NODE_EXTRA_CA_CERTSat the company root CA file in PEM format.
How to verify
Claude Code starts and answers without the certificate error.
Risks
Do not set NODE_TLS_REJECT_UNAUTHORIZED=0 (the Stack Overflow asker's own answer). It turns off TLS certificate checking for every connection.
Receipts 0 success · 0 failure · 0 partial · 0 independent successes
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