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Cryptocurrency Exchange Platform - OpenDAX

Guide | API Docs | Consulting | Community

Rango is part of OpenDAX Trading Platform


Rango is a general purpose websocket server which dispatch public and private messages from RabbitMQ. Rango is made as a drop-in replacement of Ranger built in ruby. It was designed to be very fast, scalable with a very low memory footprint.


To simplify the migration from Ranger all environement variables are the same:

RANGER_HOST Hostname to expose the websocket connection
RANGER_PORT 8080 Websocket server port
RABBITMQ_HOST localhost RabbitMQ hostname to connect to
RABBITMQ_PORT 5672 RabbitMQ port
RABBITMQ_USER guest Username used to authenticate to RabbitMQ
RABBITMQ_PASSWORD guest Password used to authenticate to RabbitMQ


Rango exposes metrics in Prometheus format on the port 4242.

Rango metrics

rango_hub_clients_count gauge Number of clients currently connected
rango_hub_subscriptions_count gauge Number of user subscribed to a topic

HTTP metrics

promhttp_metric_handler_requests_in_flight gauge Current number of scrapes being served.
promhttp_metric_handler_requests_total counter Total number of scrapes by HTTP status code.

Process metrics

process_cpu_seconds_total counter Total user and system CPU time spent in seconds.
process_max_fds gauge Maximum number of open file descriptors.
process_open_fds gauge Number of open file descriptors.
process_resident_memory_bytes gauge Resident memory size in bytes.
process_start_time_seconds gauge Start time of the process since unix epoch in seconds.
process_virtual_memory_bytes gauge Virtual memory size in bytes.
process_virtual_memory_max_bytes gauge Maximum amount of virtual memory available in bytes.

Go standard metrics

go_gc_duration_seconds{quantile} summary A summary of the pause duration of garbage collection cycles.
go_goroutines gauge Number of goroutines that currently exist.
go_info{version} gauge Information about the Go environment.
go_memstats_alloc_bytes gauge Number of bytes allocated and still in use.
go_memstats_alloc_bytes_total counter Total number of bytes allocated, even if freed.
go_memstats_buck_hash_sys_bytes gauge Number of bytes used by the profiling bucket hash table.
go_memstats_frees_total counter Total number of frees.
go_memstats_gc_cpu_fraction gauge The fraction of this program's available CPU time used by the GC since the program started.
go_memstats_gc_sys_bytes gauge Number of bytes used for garbage collection system metadata.
go_memstats_heap_alloc_bytes gauge Number of heap bytes allocated and still in use.
go_memstats_heap_idle_bytes gauge Number of heap bytes waiting to be used.
go_memstats_heap_inuse_bytes gauge Number of heap bytes that are in use.
go_memstats_heap_objects gauge Number of allocated objects.
go_memstats_heap_released_bytes gauge Number of heap bytes released to OS.
go_memstats_heap_sys_bytes gauge Number of heap bytes obtained from system.
go_memstats_last_gc_time_seconds gauge Number of seconds since 1970 of last garbage collection.
go_memstats_lookups_total counter Total number of pointer lookups.
go_memstats_mallocs_total counter Total number of mallocs.
go_memstats_mcache_inuse_bytes gauge Number of bytes in use by mcache structures.
go_memstats_mcache_sys_bytes gauge Number of bytes used for mcache structures obtained from system.
go_memstats_mspan_inuse_bytes gauge Number of bytes in use by mspan structures.
go_memstats_mspan_sys_bytes gauge Number of bytes used for mspan structures obtained from system.
go_memstats_next_gc_bytes gauge Number of heap bytes when next garbage collection will take place.
go_memstats_other_sys_bytes gauge Number of bytes used for other system allocations.
go_memstats_stack_inuse_bytes gauge Number of bytes in use by the stack allocator.
go_memstats_stack_sys_bytes gauge Number of bytes obtained from system for stack allocator.
go_memstats_sys_bytes gauge Number of bytes obtained from system.
go_threads gauge Number of OS threads created.

Start the server



In rango there are three stream scopes: public, private and prefixed.


Anyone can register to Public streams, even anonymous users, like orderbook updates, klines and tickers. AMQP message with routing key public.market_id.event ( are routed as public messages.


With Private stream the user will receive only the message addressed to him, for example its own order updates or trades. AMQP messages with routing key private.UID.event ( are routed as private messages.


Prefixed stream scopes are restricted based on user role (RBAC). For example, a specific prefix can be configured so only users with role admin or superadmin will receive messages of this stream. AMQP message with routing key (prefix).market_id.event (admin.btcusd.sys) are routed as prefixed messages.

Configure RBAC prefix streams

To allow specific user roles to connect to prefixed stream, set RANGO_RBAC_EXAMPLE env, where EXAMPLE is the name of the prefix. Without this env, nobody will be allowed to subscribe. One specific environment variable should be set for each rbac stream.

For example you can configure the streams admin, sys and accounting as follow:

export RANGO_RBAC_ADMIN=admin,superadmin
export RANGO_RBAC_SYS=admin,superadmin,operator
export RANGO_RBAC_ACCOUNTING=accountant,operator

User with role 'accountant' will received messages with route for example.

Connect to public channel

wscat --connect localhost:8080/public

Connect to private channel

wscat --connect localhost:8080/private --header "Authorization: Bearer ${JWT}"


Subscribe to a stream list


Unsubscribe to one or several streams



Barong JWT is released under the terms of the Apache License 2.0.


Maintained by Openware and used in its cryptocurrency exchange software stack.