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Node.jsNode.jsError code

ERR_HTTP_HEADERS_SENT

http headers sent

What does this code mean?

Code ERR_HTTP_HEADERS_SENT · An issue reported by Node.js.

Official explanation · Original text

An attempt was made to add more headers after the headers had already been sent.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

Errors | Node.js v26.13.1 Documentation ↗

Creator: Node.js contributors; Joyent, Inc. and other Node contributors
License: MIT License (Node.js documentation)
Checked on: 2026-11-12

Modifications: English prose extracted; whitespace normalized; Korean context and classified official links added. Python code examples not redistributed.

Source details · Original licenses and notices