---
summary: Grammar for room IDs and event IDs
---
created: 2016-04-19 11:09:19.0
creator: richvdh
description: |-
  Room IDs and Event IDs are opaque to the user (they should never be seen), but they do have some syntax within the protocol; this means that they can be more baroque than User IDs, but are not as freeform as some other IDs (SPEC-388).

  We should ensure their syntax is well-specified, and make sure we know which characters they can include.
id: '12632'
key: SPEC-389
number: '389'
priority: '1'
project: '10001'
reporter: richvdh
status: '1'
type: '2'
updated: 2016-10-28 16:28:29.0
votes: '0'
watches: '2'
workflowId: '12732'
---
actions:
- author: richvdh
  body: |-
    From [~markjh]:

    {quote}
    ... the v2 filter API makes assumptions that '*" is not a valid character in a room id or a user ID so that it can use it as a wildcard.
    {quote}
  created: 2016-04-19 12:10:21.0
  id: '12854'
  issue: '12632'
  type: comment
  updateauthor: richvdh
  updated: 2016-04-19 12:10:21.0
- author: richvdh
  body: The local-part could have the same grammar as the completely-opaque IDs (SPEC-388)?
  created: 2016-07-13 14:55:53.0
  id: '13055'
  issue: '12632'
  type: comment
  updateauthor: richvdh
  updated: 2016-07-13 14:55:53.0
- author: jimmycuadra
  body: Probably also relevant to SPEC-388, the character set should probably be limited to avoid things that would be ambiguous or "annoying" when displayed, like whitespace and newlines. Also, if the opaque ID can contain a colon, that would make it harder to figure out which colon delimits the opaque ID from the IP/hostname and from the port.
  created: 2016-07-22 23:55:07.0
  id: '13078'
  issue: '12632'
  type: comment
  updateauthor: jimmycuadra
  updated: 2016-07-22 23:55:07.0
- author: richvdh
  body: 'Migrated to github: https://github.com/matrix-org/matrix-doc/issues/667'
  created: 2016-10-28 16:28:29.0
  id: '13476'
  issue: '12632'
  type: comment
  updateauthor: richvdh
  updated: 2016-10-28 16:28:29.0