website/docs/user-guide/messaging/simplex.md

# SimpleX Chat

[SimpleX Chat](https://simplex.chat/) is a private, decentralised messaging platform where users own their contacts and groups. Unlike other platforms, SimpleX assigns no persistent user IDs — every contact is identified by an opaque internal ID generated at connection time, which makes it one of the most private messengers available.

> Run `hermes gateway setup` and pick **SimpleX** for a guided walk-through.

## Prerequisites

- The **simplex-chat** CLI installed and running as a daemon
- Python package **websockets** (`pip install websockets`)

## Install simplex-chat

Download the latest release from the [simplex-chat GitHub releases](https://github.com/simplex-chat/simplex-chat/releases) page:

```bash
# Linux / macOS binary
curl -L https://github.com/simplex-chat/simplex-chat/releases/latest/download/simplex-chat-ubuntu-22_04-x86_64 -o simplex-chat
chmod +x simplex-chat
```

The SimpleX Chat project does not publish a prebuilt Docker image for the chat client; to run it under Docker, build from source from the [simplex-chat repository](https://github.com/simplex-chat/simplex-chat).

## Start the daemon

```bash
simplex-chat -p 5225
```

The daemon listens on WebSocket at `ws://127.0.0.1:5225` by default.

## Configure Hermes

### Via setup wizard

```bash
hermes gateway setup
```

Select **SimpleX Chat** and follow the prompts.

### Via environment variables

Add these to `~/.hermes/.env`:

```
SIMPLEX_WS_URL=ws://127.0.0.1:5225
SIMPLEX_ALLOWED_USERS=<contact-id-1>,<contact-id-2>
SIMPLEX_HOME_CHANNEL=<contact-id>
```

| Variable | Required | Description |
|---|---|---|
| `SIMPLEX_WS_URL` | Yes | WebSocket URL of the simplex-chat daemon |
| `SIMPLEX_ALLOWED_USERS` | Recommended | Comma-separated allowlist. Each entry can be a numeric `contactId` **or** a display name — both forms work. |
| `SIMPLEX_ALLOW_ALL_USERS` | Optional | Set `true` to allow every contact (use carefully) |
| `SIMPLEX_AUTO_ACCEPT` | Optional | Auto-accept incoming contact requests (default: `true`) |
| `SIMPLEX_GROUP_ALLOWED` | Optional | Comma-separated group IDs the bot participates in, or `*` for any group. Omit to ignore group messages entirely |
| `SIMPLEX_HOME_CHANNEL` | Optional | Default contact/group ID for cron job delivery |
| `SIMPLEX_HOME_CHANNEL_NAME` | Optional | Human label for the home channel |
| `HERMES_SIMPLEX_TEXT_BATCH_DELAY` | Optional | Quiet-period seconds (default: `0.8`) used to concatenate rapid-fire inbound text messages into one event |

## Find your contact ID or display name

After starting the daemon, open a conversation with your agent contact. The numeric `contactId` appears in session logs. If you'd rather use the display name shown in the SimpleX UI, that works too — `SIMPLEX_ALLOWED_USERS` accepts either form.

## Authorization

By default **all contacts are denied**. You must either:

1. Set `SIMPLEX_ALLOWED_USERS` to a comma-separated list of `contactId`s and/or display names (e.g. `SIMPLEX_ALLOWED_USERS=4,alice` matches either contactId 4 or the contact whose display name is "alice"), or
2. Use **DM pairing** — send any message to the bot and it will reply with a pairing code. Enter that code via `hermes pairing approve simplex <CODE>`.

## Group chats

By default the adapter ignores group messages — a bot in a group otherwise
processes every member's traffic. Opt-in explicitly:

```
SIMPLEX_GROUP_ALLOWED=12,34          # specific group IDs
# or
SIMPLEX_GROUP_ALLOWED=*              # any group the bot is in
```

Address groups by prefixing the chat ID with `group:`, e.g.
`simplex:group:12` as a cron `deliver=` target or in a `hermes send` call.

## Sending with `hermes send`

SimpleX works as a standalone send target — the daemon must be running,
but a live gateway is not required for plain text:

```bash
hermes send --to simplex:alice "hello"          # DM by contact display name
hermes send --to simplex:group:12 "hello"       # group by numeric ID
hermes send --to simplex "hello"                # SIMPLEX_HOME_CHANNEL
```

While the gateway is running, the adapter enumerates your contacts and
allowed groups into the channel directory (refreshed every 5 minutes), so
`hermes send --list` shows them by name. Before the first gateway run the
platform still appears in `--list` with a "no channels discovered yet"
hint — direct targets like the ones above work regardless.

## Attachments

The adapter supports native SimpleX attachments in both directions:

- **Inbound** — incoming images, voice notes, and files are accepted via
  the daemon's XFTP flow (`rcvFileDescrReady` → `/freceive` → wait for
  `rcvFileComplete`) and surfaced as `MessageEvent.media_urls` with the
  appropriate `MessageType` (`PHOTO`, `VOICE`, `TEXT` + document).
- **Outbound** — `send_image_file`, `send_voice`, `send_document`, and
  `send_video` all use the structured `/_send` form with `filePath`, so
  the receiving SimpleX client renders images inline and plays voice
  notes inline rather than offering them as downloads.

Agent replies can also embed `MEDIA:/path/to/file` tags in plain text —
the adapter strips the tag from the body and sends the file as either a
voice note (audio extensions) or a document.

## Using SimpleX with cron jobs

```python
cronjob(
    action="create",
    schedule="every 1h",
    deliver="simplex",          # uses SIMPLEX_HOME_CHANNEL
    prompt="Check for alerts and summarise."
)
```

Or target a specific contact via the cron job's `deliver:` field, or from a shell script with the [`hermes send` CLI](/guides/pipe-script-output):

```bash
hermes send simplex:<contact-id> "Done!"
```

## Privacy notes

- SimpleX never reveals phone numbers or email addresses — contacts use opaque IDs
- The connection between Hermes and the daemon is local WebSocket (`ws://127.0.0.1:5225`) — no data leaves your machine
- Messages are end-to-end encrypted by the SimpleX protocol before reaching the daemon

## Troubleshooting

**"Cannot reach daemon"** — Ensure `simplex-chat -p 5225` is running and the port matches `SIMPLEX_WS_URL`.

**"websockets not installed"** — Run `pip install websockets`.

**Messages not received** — Check that the contact's ID is in `SIMPLEX_ALLOWED_USERS` or approve them via DM pairing.