---
title: Limitations
description: What Zoom's platform will not do, what this adapter has not built yet, and which is which.
---

Several of these come from Zoom and cannot be fixed here. The rest is scope. Read
this before you design a feature around threads, history, or formatting.

## Zoom's platform

### A conversation cannot be followed

Every `bot_notification` arrives with a thread ID built from its own `event_ts`,
and Zoom sends no parent or reply reference alongside it. Two messages a person
experiences as one exchange reach your bot as two unrelated threads, so
`thread.subscribe()` has nothing to hold on to.

Keep your own context — keyed by the channel JID and the user — if your bot
needs to remember what was said a moment ago.

### Replies in a DM thread never arrive

Zoom does not fire an event when someone replies inside a thread in a one-to-one
chat. Your bot can post a threaded reply into a DM, but it will never see the
answer.
([Zoom devforum](https://devforum.zoom.us/t/clarification-on-zoom-chatbot-webhook-events-for-thread-replies-in-1-1-chats/134812))

In a channel, threaded replies behave normally.

### Emoji and accents can fail signature checks

Zoom's servers may normalise emoji and accented characters differently before
signing than the bytes they deliver, so those payloads can fail HMAC
verification and come back `401`. This is tracked by Zoom as **ZOOM-506645**.

The adapter writes the first 200 bytes of the body as hex to the logger at
`debug` level when a comparison fails, which is the evidence to attach when you
contact Zoom Support citing that number.

### Some formatting has no Zoom token

Zoom's Markdown parser renders bold, italic, strikethrough, block quotes, links,
and images. It has no token for:

- **Underline** — `__text__` becomes plain text.
- **Tables** — rendered as pipe-separated text rows, with the header in bold.
- **Headings** — a heading becomes a bold line.
- **Lists** — list items become `•` bullets.

The words and data are kept; only the styling is lost. [Formatting](/formatting)
shows every mapping.

### Images only render from trusted domains

The image token is sent correctly, but the Zoom client drops images from hosts it
does not trust, logging `[Security] Blocked image from untrusted domain`. Add the
host to your app's trusted-domain list, or use one Zoom already trusts, such as
`developers.zoom.us`. This is a client-side rule; the adapter cannot override it.

## This adapter

| Not available | Why |
| --- | --- |
| Message history (`fetchMessages`, `fetchThread`) | Not implemented — the calls throw |
| Reactions | Zoom's chatbot API does not offer them |
| Typing indicator | Zoom has no such API; `startTyping()` returns quietly |
| Incremental streaming | Output is buffered and sent as one message |
| CommonJS | ESM only — `require()` will not work |

If you need history or reactions, the honest answer today is that this adapter
does not provide them. An
[issue](https://github.com/aradhyacp/zoom-chat-adapter/issues) is the right
place to say you need one.