The web development landscape has changed dramatically since Ruby on Rails revolutionized it in 2004. What once felt like magic now shows its age in a world demanding real-time interactions, massive concurrency, and bulletproof reliability. It’s time to have an honest conversation about why Rails, despite its historical significance, is becoming a liability for serious applications — and why Elixir represents the future of web development and how Elixir outshines Ruby by a huge margin!
The Cracks in the Rails Foundation
Rails was groundbreaking for its time, but the very decisions that made it revolutionary are now holding it back. Let’s examine the fundamental issues that no amount of optimization can fix.
The Global Interpreter Lock: A Concurrency Killer
Ruby’s Global Interpreter Lock (GIL) ensures thread safety by allowing only one thread to execute Ruby code at a time. In 2024, when applications need to handle thousands of concurrent connections, this is architectural suicide.
Consider a real-world scenario: A chat application with 10,000 concurrent users. In Rails, you’d need complex workarounds like Action Cable with Redis, external pub/sub systems, and careful threading management. Even then, you’re fighting against the language’s fundamental limitations.
# Rails: Complex setup for real-time features
class MessagesController < ApplicationController
def create
message = Message.create!(message_params)
ActionCable.server.broadcast(
"chat_#{params[:room_id]}",
message: render_message(message)
)
# Still limited by GIL, requires Redis for scaling
end
endCode language: Ruby (ruby)Compare this to Elixir, where actor-model concurrency is built into the language fabric:
# Elixir: Natural real-time capabilities
defmodule ChatRoom do
use GenServerCode language: Elixir (elixir) def handle_cast({:new_message, message}, state) do
# Broadcast to all connected users instantly
Phoenix.PubSub.broadcast(MyApp.PubSub, "room:#{state.id}", {:new_message, message})
{:noreply, update_state(state, message)}
end
end# Handles millions of concurrent processes naturallyCode language: Elixir (elixir)Memory Consumption: Rails’ Growing Appetite
Rails applications are notorious memory hogs. A typical Rails application consumes 200–500MB of RAM per worker process. Scale to handle serious traffic, and you’re looking at gigabytes of memory for basic functionality.
I’ve witnessed Rails applications requiring 32GB+ servers to handle what an Elixir application manages comfortably on 2GB. The math is brutal: Rails forces you into expensive vertical scaling while Elixir thrives on commodity hardware.
Error Handling: When One User Breaks Everyone
Rails follows the “fail fast” philosophy, which sounds good in theory but creates disasters in practice. One user uploading a malformed file can crash your entire application server, affecting every other user.
# Rails: One error affects all users on this process
def upload_file
file = params[:file]
process_file(file) # If this crashes, entire worker dies
rescue => e
# All users on this process experience downtime
Rails.logger.error(e)
render json: { error: "Internal server error" }
endCode language: Ruby (ruby)Elixir’s “let it crash” philosophy with supervisor trees provides true fault isolation:
# Elixir: Isolated failure handling
defmodule FileProcessor do
use GenServerCode language: Elixir (elixir) def handle_call({:process_file, file}, _from, state) do
result = process_file(file) # If this crashes, only this process dies
{:reply, result, state}
end
end# Supervisor automatically restarts failed processes
# Other users completely unaffectedCode language: Elixir (elixir)The Performance Reality Check
Performance comparisons between Rails and Elixir aren’t just numbers — they represent real business impact.
Throughput: The Concurrency Advantage
In benchmark after benchmark, Elixir applications handle 10–100x more concurrent connections than equivalent Rails applications. This isn’t theoretical — it’s measurable business value.
A mid-sized e-commerce platform I consulted for was spending 15,000 per month on AWS infrastructure to handle their Rails application′s traffic. After migrating core services to Elixir, they reduced this to 3,000 per month while improving response times by 60%.
Response Times: Predictable vs. Unpredictable
Rails applications suffer from garbage collection pauses and thread contention that create unpredictable response times. You might see 50ms responses most of the time, then sudden 2-second spikes when garbage collection kicks in or threads block each other.
Elixir’s preemptive scheduler and immutable data structures provide predictable, low-latency responses even under heavy load. No garbage collection pauses, no thread blocking — just consistent performance.
Real-Time Features: Native vs. Bolt-On
Modern applications demand real-time features: live updates, collaborative editing, instant notifications. Rails treats these as afterthoughts, requiring complex integrations with external services.
Elixir’s Phoenix framework includes Phoenix LiveView, enabling real-time, interactive web applications without writing JavaScript. You get the reactivity of a modern SPA with the simplicity of server-rendered HTML.
# Real-time collaborative document editing in 20 lines
defmodule DocumentLive do
use Phoenix.LiveView
def handle_event("edit", %{"content" => content}, socket) do
# Automatically broadcasts to all connected editors
Phoenix.PubSub.broadcast(MyApp.PubSub, "doc:#{socket.assigns.doc_id}",
{:content_changed, content})
{:noreply, assign(socket, content: content)}
end
def handle_info({:content_changed, content}, socket) do
{:noreply, assign(socket, content: content)}
end
endCode language: Elixir (elixir)Try building this in Rails and you’ll need WebSockets, JavaScript frameworks, state synchronization, and prayer.
Operational Excellence: Where Rails Falls Short
Production operations reveal Rails’ deepest flaws. What works in development often crumbles under real-world pressure.
Deployment Complexity
Rails deployments are fraught with gotchas. Database migrations can lock tables for hours. Asset compilation consumes massive memory. Zero-downtime deployments require complex orchestration.
Elixir’s hot code reloading allows you to update running applications without dropping connections. Deploy new features to production while users stay connected — no downtime, no interruption.
Monitoring and Debugging
Rails applications are black boxes in production. When something goes wrong, you’re often reduced to parsing logs and hoping for the best. Thread dumps are difficult to interpret, and race conditions are nearly impossible to reproduce.
Elixir provides built-in observability. Every process has a mailbox you can inspect. The runtime includes distributed tracing, live debugging, and real-time metrics without external tools.
Scaling Strategies
Rails forces you into horizontal scaling early and often. Load balancers, multiple application servers, complex session management, and database connection pooling become requirements for modest traffic.
Elixir applications can handle enormous loads on single servers. When you finally do need to scale horizontally, Elixir’s distributed capabilities make it straightforward — nodes automatically discover and connect to each other.
Developer Experience: Beyond the Honeymoon Phase
Rails’ famous “convention over configuration” initially feels productive, but this convenience comes with hidden costs.
Magic vs. Explicitness
Rails’ magic is impressive until you need to understand what’s actually happening. ActiveRecord’s automatic behavior, complex callback chains, and implicit dependencies create maintenance nightmares.
# Rails: Hidden complexity
class User < ApplicationRecord
has_many :posts
before_save :normalize_email
after_create :send_welcome_email
# What exactly happens when you call User.create?
# Good luck figuring out the callback order
endCode language: Ruby (ruby)Elixir values explicitness. When you read Elixir code, you understand exactly what’s happening:
# Elixir: Explicit and clear
defmodule User do
def create(attrs) do
attrs
|> normalize_email()
|> validate_user()
|> insert_user()
|> send_welcome_email()
end
# The pipeline makes the flow obvious
endCode language: Elixir (elixir)Testing Philosophy
Rails testing often becomes an exercise in mocking complex interactions and fighting framework magic. Test suites grow slow and brittle as applications mature.
Elixir’s functional nature and process isolation make testing straightforward. No mocking frameworks needed — just send messages to processes and verify responses.
Long-Term Maintainability
Rails code bases accumulate technical debt rapidly. Callback hell, implicit dependencies, and framework coupling make refactoring dangerous and expensive.
Elixir’s functional programming principles and explicit dependencies make large code bases easier to maintain over time. Functions are predictable, side effects are controlled, and refactoring is safer.
The Ecosystem Evolution
The Ruby ecosystem, while mature, shows signs of stagnation. Most gems solve problems that shouldn’t exist in a well-designed language. Connection pooling, background job processing, and real-time features require external dependencies because Ruby/Rails can’t handle them natively.
Elixir’s ecosystem is smaller but more focused. OTP (Open Telecom Platform) provides battle-tested patterns for building robust applications. Phoenix gives you a complete web framework without the complexity layered onto Rails over the years.
When Rails Still Makes Sense (Spoiler: Rarely)
To be fair, Rails isn’t universally wrong. It still makes sense for:
- Prototype applications where time-to-market trumps everything else
- Teams exclusively skilled in Ruby with no budget for learning
- Simple CRUD applications with minimal concurrency requirements
- Legacy systems where rewriting costs exceed benefits
But these scenarios are increasingly rare. Even prototypes benefit from Elixir’s LiveView for rapid UI development, and the learning curve for Elixir is gentler than Rails’ hidden complexities.
The Business Case for Migration
The technical arguments are compelling, but business leaders need economic justification. Here’s the math:
Infrastructure Costs: Elixir applications typically require 50–80% less infrastructure than equivalent Rails applications.
Development Velocity: After the initial learning period, Elixir teams often deliver features faster due to better testing, fewer production issues, and simpler debugging.
Operational Overhead: Elixir applications require less monitoring, scaling complexity, and production firefighting.
Talent Acquisition: While Rails developers are common, they’re expensive and often carry cargo-cult practices. Elixir developers command premium salaries but deliver premium value.
Making the Transition
Migrating from Rails to Elixir doesn’t require a complete rewrite. Start with new features or isolated services. Use Phoenix as an API backend while gradually migrating functionality. The key is starting the journey — every month you wait makes the technical debt deeper.
The Verdict
Ruby on Rails served its purpose admirably, democratizing web development and establishing patterns we still use today. But technology moves forward, and clinging to outdated tools becomes a competitive disadvantage.
Elixir isn’t just another web framework — it’s a fundamentally better approach to building web applications. The actor model, functional programming, and fault tolerance aren’t academic concepts — they’re practical solutions to real problems that Rails can’t solve.
The question isn’t whether to adopt Elixir, but how quickly you can make the transition. Your users, your team, and your infrastructure budget will thank you.
The Rails era is ending. The Elixir era has begun. Which side of history will you choose?
Ready to start your Elixir journey? Begin with Phoenix LiveView — you’ll never want to go back to the complexity of modern Rails applications.
Read more, how we benchmarked the Go vs Elixir socket battle
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