Deploy with Confidence

Battle-hardened by some of the most demanding web apps for over a decade, Passenger® is considered one of the most performant, secure and mature app servers currently available.

User Friendly

We've made sure Passenger remains incredibly easy to set up and use.

One command

That’s all it takes to run our automated installer! Passenger’s installation process includes either automatic NGINX or automatic Apache integration to reduce work and moving parts on your end.

Passenger also plays nicely with other tech that is commonly found in today’s server stacks, like Docker.
Rubygem, APT and YUM packages
Docker integration & more
Features stars Features secure Features analysis Features resilient ship Features watchdog Features rock1 Features rock2 Features rock3 Features rock4

Reliable & Secure

Passenger was designed with security and stability in mind. This kind of attention to detail allows you to use Passenger to power even the most business critical apps with confidence.


Passenger quietly restarts applications that crash, hang, or leak memory. Application updates don't interrupt the service, and error resistance stops flawed updates.


Passenger defends against slow client attacks and common HTTP parser exploits, and uses privilege separation to keep intruders contained.


Passenger experiences fewer dropped or errored requests than other app servers, and can limit application memory use and response times.


Root out issues like stuck apps or memory leaks with request inspection, backtrace dumps, and accurate CPU and memory stats.

Easy debugging

Inspect or modify code on the fly by attaching a live IRB console, Ruby debugger, or low-level GDB to your running app.


The new standard in DevOps, Passenger® 6 is infrastructure independent.

Fast, Efficient & Scalable

Passenger utilizes C++ to leverage the bare metal of your servers as much as possible for maximum efficiency and performance. Passenger also supports evented I/O for maximum scalability.


Passenger leverages your CPU’s hardware cache to serve up pages at up to 100x higher rates than competing solutions. Unlike alternative solutions, this built-in feature can be enabled with a single line config.
Features turbocaching Turbocaching leverages your CPU’s ultrafast L1 and L2 caches to store & access data on. This minimizes the need for the CPU to do data fetch cycles to RAM, and can result in 100x more requests p/sec.

Outstanding Features

Passenger utilizes Vectored IO (a.k.a. scatter/gather IO) internally to prevent the copying of buffer data needlessly during concatenation. This means that Passenger is extremely memory-efficient and minimizes the amount of system calls to achieve maximum CPU efficiency!
Zero copy

Maximum Scalability

Passenger supports evented I/O and multiple concurrency models to ensure that requests are handled both rapidly and efficiently from a single Passenger instance.
Features more stars

Premium Features

The premium features are for businesses that want to go the extra mile to deliver the best quality of life for their web apps and customers.
Rolling restarts

Rolling Restarts

Redeploy your application without downtime or large memory overhead to reduce cost and minimize customer impact.

Multithreading Ruby only

Optimize your applications’ use of CPU power and memory for the most efficient use of your hardware.
Error resistance

Error Resistance

Automatically cancel deployment when Passenger detects errors, to minimize customer impact.
Live debugging

Live Debugger Ruby only

Allow your engineers to connect to your live application to find and resolve issues without impacting performance.
Mass deployment

Mass Deployment

Easily manage hundreds of applications with a single command and save big on operational costs.
Resource limiting

Resource Limits

Passenger curbs application resource use to ensure stability and reduce operational costs.

Comparison Table

Passenger is currently one of the most feature rich app servers available. Here's how it compares to others. But why not also experience it for yourself? get started in 10 minutes
Passenger enterprise
Passenger open source
Multi-CPU-Core Utilization
Fair Traffic Distribution
Copy-On-Write Preloading
Request Buffering
WebSocket-compatible Response Buffering
Basic Documentation and Config Reference
In-Depth Documentation (End-To-End Tutorials, Use Cases, Related Tools)
Deep Web Server Integration
Process Autoscaling
Multitenant (n apps, 1 instance)
Generic Language Support
Automatic Privilege Separation
OS Packages (APT, RPM)
CPU / Memory / Process Stats
Memory-efficient Zero-downtime
Rolling Restarts
Error Detection
Live Debugging
Mass Deployment
Downtime Prevention
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