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SignalR vs Socket.IO

Discover how SignalR compares to Socket.IO, and understand which is right for your use case, based on dimensions such as core features, pricing, reliability, and scalability.

What is SignalR?

An open-source library that simplifies adding real-time web functionality to apps. It is integrated into the ASP.NET Core web development stack and provides a mechanism for two-way remote procedure calls between client and server.

Suitable for:

  • Apps that require high frequency updates from the server, like gaming, social networks, voting, auction, maps, and GPS apps.
  • Dashboards and monitoring apps
  • Collaborative apps
  • Apps that require notifications

Not suitable for:

-Stateless applications -Apps with high scalability requirements -Apps with high throughput requirements

Pros:

  • Open source
  • Free to use

Cons:

  • Self-hosted
  • Complex to manage

What is Socket.IO?

Socket.IO is a library created in 2010 that provides realtime, bi-directional communication between clients and servers. It allows the management of connections, sending and receiving messages, and more. Built on top of the WebSocket protocol, it provides additional capabilities compared to raw WebSockets. WebTransport (a WebSocket alternative) is also supported.

Suitable for:

  • Chat and messaging
  • Dashboards
  • Mulitplayer games

Not suitable for:

  • Audio & video

Pros:

  • Multiplexing and data broadcast support
  • Disconnection detection and automatic reconnections
  • Adapters for horizontal scaling
  • Fallback support

Cons:

  • Message ordering guarantees are at most once / least once only
  • Memory leakage issues
  • Not multi-region

Compare SignalR and Socket.IO

Let’s compare SignalR and Socket.IO, looking at key dimensions such as their core features, pricing, integrations, QoS, performance, and security and compliance.

Disclaimer:This comparison was created based on documentation and resources freely available online about SignalR and Socket.IO. The content was last updated on 11 Jul 2024 for SignalR and on 10 Jun 2024 for Socket.IO. Be sure to double-check everything before you make any decisions. If you do find anything incorrect or out of date, then please contact us.

Core features
Pub/Sub messaging

Reduces communication code complexity, simplifying the process of building highly functional and architecturally complex realtime apps.

SignalR

Partial

The SignalR SDKs do not provide a topic abstraction out of the box, but they provide a "groups" abstraction which lets you implement something similar.

Read more
Socket.IO

No

Need to rely on a third party - e.g. use a Redis adapter to broadcast events to clients through the Redis pub/sub mechanism.

Read more
Chat capabilities

Accelerates the time to implement rich chat experiences with features such as read receipts, typing indicators, and more.

SignalR

Yes

SignalR (ASP.net) allows you to implement chat capabilities.

Read more
Socket.IO

Partial

As it's a library, you need to create the chat capabilities yourself. But this can be done using Socket.IO.

Collaboration capabilities

Enables you to quickly integrate realtime collaborative features like live cursors, member location, avatar stacks, and component locking.

SignalR

No

Socket.IO

Partial

As it's a library, you need to implement collaboration capabilities yourself. But you can do this using Socket.IO itself.

State sync capabilities

Enables realtime data synchronization across devices and users, ensuring a cohesive and up-to-date user experience.

SignalR

No

Socket.IO

No

The library does not support this. You would need to create a bespoke state sync capability or integrate a third party library to get state synchronisation.

Presence

Maintaining a view of which users are connected, and their associated metadata, enables their online status to be updated in realtime.

SignalR
Socket.IO

Partial

It is the duty of your application to link a Socket.IO connection to a user account.

Read more
Occupancy

High-level metrics about the clients currently connected to a channel make it simple to show things such as connected user count, or display which channels are the most popular.

SignalR

No

Socket.IO

Partial

Rooms are available. It is possible to query for rooms and SIDs.

See more
Message interactions

Enables interaction with previously-sent messages, facilitating the implementation of features like message reactions and threads.

SignalR

No

Socket.IO

Partial

You would need to build the message interaction functionality yourself on top of Socket.IO.

Learn more
Message history

Enables clients to catch up on missed messages when inactive, ensuring a user doesn’t miss any important messages.

SignalR

No

Socket.IO

No

The Socket.IO server does not store messages. Your application has to persist messages somewhere for the clients that are not currently connected.

Learn more
Push notifications

Cross-platform push notifications make it possible to deliver important and timely messages to users even when they’re inactive.

SignalR

No

Microsoft Azure Web PubSub has no native push notification functionality. Microsoft has a separate service for this - Azure Notification Hubs.

Read more
Socket.IO

No

Socket.IO not support Push notifications. You would need to build this capability yourself and/or use another library.

Learn more
Message delta compression

Minimizes bandwidth and can reduce latency, particularly in scenarios where continuous updates are sent.

SignalR

No

Socket.IO

No

Programmatic management

Enables the automation of provisioning, management, and testing of service resources, simplifying integration with existing development workflows such as CI.

SignalR

No

Socket.IO

Yes

The Socket.IO server is initialised in code. It is possible to configure the socket.IO server's configuration in code as well.

Learn more
Pricing
Free plan

With a free plan, you can test the service’s functionality and compatibility with your project before committing to a paid plan.

SignalR

Yes

Self-hosted and free.

Socket.IO

Yes

Open Source framework that uses the MIT license.

Pricing model

The pricing model should align with your project's expected load, usage patterns, and budget in order to be cost-effective and efficient.

SignalR

N/A (self-hosted)

Socket.IO

Open Source framework that uses the MIT license.

Integrations & interoperability
SDKs

Supporting multiple languages and platforms offers greater flexibility when building cross-platform realtime apps.

SignalR

Client SDKs:

  • ASP.NET Core
  • Java
  • JavaScript (browser, Node)
  • C++ (experimental)
  • Swift (experimental)

Server SDKs:

  • ASP.NET Core
Socket.IO

Client and Server APIs only.

  • C++
  • Swift
  • Java
  • Javascript
  • Typescript
  • Node.js
  • Python
  • Golang
  • Rust
  • Dart
  • .NET
  • Kotlin
Supported realtime protocols

Support for multiple protocols provides the flexibility to choose a protocol that best suits your project’s requirements.

SignalR
  • WebSockets
  • Server-sent events (SSEs)
  • Long polling
Socket.IO
  • WebSocket
  • WebTransport
  • HTTP
Serverless functions

Enables integration with third-party cloud providers by facilitating the execution of custom code against messages to perform business logic like on-the-fly translation.

SignalR

None.

Socket.IO

No

It is not possible to trigger serverless functions with Socket.IO on it's own.

See this Reddit post for more info
Streaming & queueing

Provides a dependable method to reroute messages from the service to third-party streams and queues for further processing.

SignalR

No

Socket.IO

No

Socket.IO does not offer native queues and streaming.

Observability services

Enables realtime monitoring and troubleshooting by offering insights into service behavior directly in your observability platform of choice.

SignalR

Partial

SignalR is integrated with ASP.net Core metrics, and these can be reported to a monitoring system at regular intervals.

Read more
Socket.IO

Yes

The Socket.IO admin UI can be used to have an overview of the state of your Socket.IO deployment.

CI/CD tools

Makes it possible to provision and configure service infrastructure as part of a CI or CD pipeline, enabling repeatable and reliable deployments.

SignalR

No

Self-hosted, so you will have to implement your own.

Socket.IO

No

Quality of Service
Scalability

Scalability is vital as it ensures the service can handle increased data load or users without compromising performance.

SignalR

N/A (self-hosted)

Socket.IO

No published metrics. Socket.IO servers don’t communicate between them, so you need a way to route events to all clients, even if they are connected to different servers. This is made possible by using adapters, of which the Redis adapter seems to be the most popular choice.

Guaranteed message delivery

Ensures messages are never lost during transmission, even in the presence of network disruptions.

SignalR

No

Socket.IO

Partial

By default, Socket.IO provides an "at most once" guarantee of delivery. From the client side, you can achieve an at least once guarantee with acknowledgements and timeouts.

Guaranteed message ordering

Maintains the sequence of messages as they were sent. This is particularly important in apps where the chronological order of messages is essential for meaningful communication.

SignalR

No

Socket.IO

Yes

Socket.IO guarantees ordering, no matter which low-level transport is used.

Read more
Exactly-once message delivery

Guarantees that each message is processed exactly once, preventing data inconsistencies that can arise from duplicate processing or missing messages.

SignalR

No

Socket.IO

No

At least once or at most once only.

Performance & availability
Uptime Guarantee

An uptime guarantee instills confidence in the reliability of the service and protects your business from the negative impacts of downtime.

SignalR

N/A

Socket.IO

No

It is a library, not a platform.

Global edge network

By bringing servers (Points of Presence, or PoP) geographically closer to the devices of end users, and routing requests to the nearest PoP, global latency is reduced to a minimum.

SignalR

No

Socket.IO

No

Multi-region data replication (message durability)

By replicating data across multiple regions, the risk of data loss or downtime is greatly mitigated since if data is lost or a server fails in one region, the information can be retrieved from another.

SignalR

No

Socket.IO

No

No single point of failure or congestion

Having no single point of failure means a system is resilient and can continue to operate even if one part fails. Avoiding a single point of congestion ensures messages flow efficiently across the system and avoids bottlenecks that could lead to performance issues under load.

SignalR

No

Socket.IO

No

As Socket.IO is a library, the implementation of it dictates points of failure and congestion.

Latency

Low latency is crucial for realtime apps as it ensures swift and efficient data transmissions, providing a smoother and more responsive user experience.

SignalR

N/A (self-hosted)

Socket.IO

Unknown

Security & compliance
API key authentication

Simplifies the authentication code on trusted servers compared to requesting, managing, and refreshing tokens.

SignalR

No

Socket.IO

No

Token-based authentication

Provides a means to securely authenticate user devices against your user management system.

SignalR

Yes

It is possible to use token based authentication with ASP.net Core.

Read more
Socket.IO

No

No native Token based auth. It is possible to use middlewares.

Single Sign-On (SSO) authentication

SSO streamlines login processes, boosts security by minimizing password use, and meets compliance needs for secure data access management.

SignalR

Yes

This is possible in conjunction with an identity platform like Microsoft Entra.

Read more
Socket.IO

No

No native SSO. It is possible to use middlewares.

Rules for permissions and operations

Provides control over which users can subscribe and publish to certain channels.

SignalR

Yes

You can restrict access to hubs and hub methods to users matching specific authorization policies.

Read more
Socket.IO

No

End-to-end encryption

Ensures that the data transmitted between the client and the API server remains confidential and secure while in transit.

SignalR

No

You would need to implement this yourself.

Socket.IO

No

Encryption at rest

Ensures data stored by the service is secure and compliant, while also mitigating the risks of a data breach.

SignalR

No

Socket.IO

No

Compliance

Compliance with regulations can impact your ability to meet legal obligations in your industry.

SignalR

N/A

Socket.IO

None.

Alternatives to SignalR and Socket.IO

Whilst both SignalR and Socket.IO are worth considering as options for realtime experiences, they aren’t without their limitations. We suggest evaluating them against the following alternatives to make sure you find the right solution for your needs.

Alternatives to SignalR

Socket.IO is a library that provides realtime, bi-directional communication between clients and servers. It allows the management of connections, sending and receiving messages, and more.

Microsoft Azure Web PubSub is a fully managed PubSub offering. It is available as part of Microsoft's Azure Cloud Computing platform.

Pusher is a first-generation pub/sub messaging service that provides bi-directional hosted APIs for adding realtime features to applications.

Alternatives to Socket.IO

Azure SignalR is an Azure-hosted, fully managed realtime framework built on top of an open-source software library for Microsoft ASP.NET.

PubNub is a developer API platform that powers the realtime infrastructure in apps to build engaging Virtual Spaces where online communities can connect.

Pusher is a first-generation pub/sub messaging service that provides bi-directional hosted APIs for adding realtime features to applications.

Discover how SignalR and Socket.IO stack up against Ably

Ably is the definitive realtime experience platform of the internet. See how we compare to SignalR and Socket.IO on key dimensions such as core features, pricing, integrations, QoS, performance, and security and compliance.

Try Ably for free to discover the benefits for yourself

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  • 6M Monthly messages
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