What input format is expected?

Hex bytes, with or without spaces or 0x prefixes.

Are masked frames supported?

Yes, the masking key is applied to reveal the payload.

Which opcodes are recognised?

Text, binary, close, ping, pong and continuation frames.

WebSocket Frame Explainer

Decode WebSocket frame bytes into opcode, flags, mask and payload.

Works Offline

Privacy First

No Login

No API

WebSocket frame (hex bytes)

Paste raw frame bytes as hex (spaces/colons/0x ignored) — e.g. captured from a packet dump.

Decoded frame

FIN

1 (final)

Opcode

1 (Text)

Masked

Yes (client→server)

Payload length

5 bytes

Header bytes

Total frame size

Mask key: 37 fa 21 3d

Decoded text payload

Hejlo

About the WebSocket Frame Explainer

Paste hex bytes from a WebSocket frame to decode the FIN bit, opcode, mask flag, payload length and unmasked payload, with each field explained.

Examples

Example

81 05 48 65 6c 6c 6f

Output

Text frame, FIN=1, payload: Hello

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Frequently asked questions

Version 1.0.0 · Updated 2026-08-09 · Runs entirely in your browser