mosquitto_passwd - manage password files for mosquitto

mosquitto_passwd [-H hash] [-c | -D] passwordfile username

mosquitto_passwd [-H hash] -b passwordfile username password

mosquitto_passwd -U passwordfile

mosquitto_passwd is a tool for managing password files for the mosquitto MQTT broker.

Usernames must not contain ":". Passwords are stored in a similar format to crypt(3).


Run in batch mode. This allows the password to be provided at the command line which can be convenient but should be used with care because the password will be visible on the command line and in command history.


Create a new password file. If the file already exists, it will be overwritten.


Delete the specified user from the password file.


Choose the hash to use. Can be one of sha512-pbkdf2 or sha512. Defaults to sha512-pbkdf2. The sha512 option is provided for creating password files for use with Mosquitto 1.6 and earlier.


This option can be used to upgrade/convert a password file with plain text passwords into one using hashed passwords. It will modify the specified file. It does not detect whether passwords are already hashed, so using it on a password file that already contains hashed passwords will generate new hashes based on the old hashes and render the password file unusable.


The password file to modify.


The username to add/update/delete.


The password to use when in batch mode.

mosquitto_sub returns zero on success, or non-zero on error. If the connection is refused by the broker at the MQTT level, then the exit code is the CONNACK reason code. If another error occurs, the exit code is a libmosquitto return value.

MQTT v3.1.1 CONNACK codes:

0 Success
1 Connection refused: Bad protocol version
2 Connection refused: Identifier rejected
3 Connection refused: Server unavailable
4 Connection refused: Bad username/password
5 Connection refused: Not authorized

MQTT v5 CONNACK codes:

0 Success
128 Unspecified error
129 Malformed packet
130 Protocol error
131 Implementation specific error
132 Unsupported protocol version
133 Client ID not valid
134 Bad username or password
135 Not authorized
136 Server unavailable
137 Server busy
138 Banned
139 Server shutting down
140 Bad authentication method
141 Keep alive timeout
142 Session taken over
143 Topic filter invalid
144 Topic name invalid
147 Receive maximum exceeded
148 Topic alias invalid
149 Packet too large
148 Message rate too high
151 Quota exceeded
152 Administrative action
153 Payload format invalid
154 Retain not supported
155 QoS not supported
156 Use another server
157 Server moved
158 Shared subscriptions not supported
159 Connection rate exceeded
160 Maximum connect time
161 Subscription IDs not supported
162 Wildcard subscriptions not supported

Add a user to a new password file:

•mosquitto_passwd -c /etc/mosquitto/passwd ral

Delete a user from a password file

•mosquitto_passwd -D /etc/mosquitto/passwd ral

mosquitto bug information can be found at

mosquitto(8), mosquitto.conf(5), mqtt(7)

Roger Light <>

08/16/2022 Mosquitto Project