Foundation or terminal standard

NAWS

Negotiate About Window Size

Widely used Documented current use

Lets the client report terminal columns and rows and send later resize changes.

Protocol overview

First seen: 1988
Present-day status: Widely used
In use today?: Yes, with documented current use.
Legacy?: No.
Layer: Foundation or terminal standard
Transport: Telnet option 31 with two unsigned 16-bit dimensions
Telnet option: 31
Research validated: 2026-08-29

Current use and fit

Broadly supported by current clients and engines.

Implementation essentials

Parse width and height as network-order 16-bit values.
Handle Telnet IAC escaping inside subnegotiation.
Update layout when resize reports arrive.

Compatibility and safety notes

Dimensions are client-reported and may be zero or implausible.
Display width differs from raw UTF-8 byte length.

Original specifications and sources

RFC 1073 NAWS Standard

Where an original site has disappeared, a preservation archive is linked and identified as such. MUDVerse does not claim authorship of the original protocol.