# Billing Headers for WebSocket Endpoints

By Steven Van · 2026-09-14

Shared WebSocket endpoints on fal can now bill by declared unit counts instead of only by connection duration.

fal now lets shared [fal](<https://creatorstoolbox.com/tools/fal>) WebSocket endpoints declare billing on their 101 upgrade response instead of being charged purely by connection duration. An endpoint can set **x-fal-billable-units** when the unit count is already known at connect time, or set **x-fal-billable-units-webhook** to 1 when the count is only known once the session ends, then report the total with a POST /requests/billable-units/{request\_id} call. Endpoints that set neither header are still billed by duration, as before. More detail is in the [announcement](<https://docs.fal.ai/changelog#september-14-2026>).

[![](<https://fal-d8505a2e.mintlify.app/logo/light.svg>)](<https://docs.fal.ai/changelog#september-14-2026>)

![fal](<https://fal.ai/icon-512.png>)

fal

A generative media platform and inference API for running fast image, video, and audio AI models at scale.

[View fal →](<https://creatorstoolbox.com/tools/fal>)

Sources

[Original source](<https://docs.fal.ai/changelog#september-14-2026>)

[Read Billing Headers for WebSocket Endpoints on Creators Toolbox](<https://creatorstoolbox.com/blog/fal-billing-headers-for-websocket-endpoints>)

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Canonical source: https://creatorstoolbox.com/blog/fal-billing-headers-for-websocket-endpoints