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

SimpleX Chat

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 page:

# 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.

Start the daemon

simplex-chat -p 5225

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

Configure Hermes

Via setup wizard

hermes setup gateway

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 contact IDs allowed to use the agent
SIMPLEX_ALLOW_ALL_USERS	Optional	Set true to allow every contact (use carefully)
SIMPLEX_HOME_CHANNEL	Optional	Default contact ID for cron job delivery
SIMPLEX_HOME_CHANNEL_NAME	Optional	Human label for the home channel

Find your contact ID

After starting the daemon, open a conversation with your agent contact. The contact ID will appear in session logs or via hermes send_message action=list.

Authorization

By default all contacts are denied. You must either:

1. Set SIMPLEX_ALLOWED_USERS to a comma-separated list of contact IDs, or
2. Use DM pairing — send any message to the bot and it will reply with a pairing code. Enter that code via hermes gateway pair.

Using SimpleX with cron jobs

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

Or target a specific contact:

send_message(target="simplex:<contact-id>", message="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.