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@fastify/websocket

What changed in @fastify/websocket 9 to 11, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-27.

1 new APIs and options5 fixes and other

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@fastify/websocket 114 changes

Fixes and other changes 4

  • The handler in route() is now typed as a websocket handler when websocket: true is set.

    11.3.3release notes

  • Socket errors during upgrade hooks are now handled.

    11.3.2release notes

  • The custom server upgrade listener is removed when the server closes.

    11.3.1release notes

  • Raw socket error events are now routed through the errorHandler option.

    11.3.1release notes

@fastify/websocket 101 changes

Fixes and other changes 1

  • Provides websocket instead of stream to avoid potential backpressure issues.

    10.0.0release notes

@fastify/websocket 91 changes

New APIs and options 1