Alternatives to Socket.IO
Compare Socket.IO alternatives for your business or organization using the curated list below. SourceForge ranks the best alternatives to Socket.IO in 2026. Compare features, ratings, user reviews, pricing, and more from Socket.IO competitors and alternatives in order to make an informed decision for your business.
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1
Azure Web PubSub
Microsoft
Azure Web PubSub is a fully managed service that enables developers to build real-time web applications using WebSockets and the publish-subscribe pattern. It supports native and serverless WebSockets, allowing for scalable, bi-directional communication without the need to manage infrastructure. This service is ideal for applications such as chat rooms, live broadcasting, and IoT dashboards. Supports real-time publish-subscribe messaging for web application development through native and serverless WebSocket support. Built-in support for large-scale client connections and highly available architectures, enabling applications to handle numerous simultaneous users. Offers support for a wide variety of client SDKs and programming languages, facilitating seamless integration into existing applications. Provides built-in security features, including Azure Active Directory integration and private endpoints, to help protect data and manage access. -
2
ejabberd
ProcessOne
ejabberd XMPP server simplifies critical administration and key usage statistics through an easy-to-use and customizable management module for administrators. ejabberd XMPP server statistics module is compatible with Nagios, the industry standard IT infrastructure monitoring tool. ejabberd XMPP server supports more interaction with the browser and the web app, facilitating real-time messaging. The use of WebSockets provides the ability to seamlessly send and receive messages while a browser tab is opened. BOSH capability is provided as a fallback for XMPP server connection. ejabberd XMPP server mobile reliability layer helps manage mobile network’s disconnection, message deliveries, consistent conversation on any online device, IoT, chat server, IM service, push notification and mobile interfaces. -
3
MigratoryData
MigratoryData
Enterprises running real-time web and mobile apps struggle with latency, bandwidth, and scalability issues, which negatively impact the total cost of ownership as well as the real-time experience of their users. These issues are inherent to the traditional techniques, such as HTTP polling or long polling, employed to achieve real-time communication using web and application servers. To overcome these issues, we created MigratoryData, a real-time messaging technology leveraging the WebSockets standard, streaming data to and from users over persistent WebSocket connections in milliseconds and with minimal traffic overhead. Unlike other real-time messaging technologies, MigratoryData has been designed to scale to a large number of users. It has been benchmarked to stream real-time data to 10 million concurrent users from a single commodity server. -
4
AIOHTTP
AIOHTTP
Supports both client and server side of HTTP protocol, both client and server web-sockets out-of-the-box, and avoids callback hell and web-server with middlewares and pluggable routing. -
5
Kestrel
Microsoft
Kestrel is a cross-platform web server for ASP.NET Core. Kestrel is the web server that's included and enabled by default in ASP.NET Core project templates. Kestrel supports HTTPS, HTTP/2 (except on macOS), Opaque upgrade used to enable WebSockets, Unix sockets for high performance behind Nginx. Kestrel is supported on all platforms and versions that .NET Core supports. Some browsers require granting explicit permission to trust the local development certificate. Project templates configure apps to run on HTTPS by default and include HTTPS redirection and HSTS support. The Kestrel web server has constraint configuration options that are especially useful in Internet-facing deployments. There's a separate limit for connections that have been upgraded from HTTP or HTTPS to another protocol (for example, on a WebSockets request). The default maximum request body size is 30,000,000 bytes, which is approximately 28.6 MB. -
6
websockets
Python Software Foundation
An implementation of the WebSocket Protocol (RFC 6455 & 7692). websockets is a library for building WebSocket servers and clients in Python with a focus on correctness, simplicity, robustness, and performance. Built on top of asyncio, Python’s standard asynchronous I/O framework, it provides an elegant coroutine-based API. websockets is heavily tested for compliance with RFC 6455. Continuous integration fails under 100% branch coverage. websockets is built for production. For example, it was the only library to handle backpressure correctly before the issue became widely known in the Python community. Memory usage is optimized and configurable. A C extension accelerates expensive operations. It’s pre-compiled for Linux, macOS, and Windows and packaged in the wheel format for each system and Python version. websockets takes care of everything under the hood so you can focus on your application!Starting Price: Free -
7
Pusher Channels
Pusher
Pusher Channels is a hosted API which allows you to quickly and easily bring rich realtime features to your apps; from dashboards to gaming, collaborative editing, live maps and more, simplify your stack and simply integrate Pusher’s managed WebSocket connections to build the features your users expect into any web or mobile app. Whenever something changes in your system a single API call to Channels will prompt a WebSocket update so that you can instantly update the UI in your users’ apps. Whether you have one connection or millions, ultra-low latency with automatic fallback means Channels works anywhere. Pusher delivers billions of messages every month across browsers, mobile and IoT with the event-based API. Pusher manages and scales the realtime infrastructure, as a reliable and cost-effective alternative to building, maintaining and scaling in-house, so you can concentrate on your product.Starting Price: $49 -
8
Cowboy
99s
Cowboy is the ultimate server for the modern Web with support for Websocket, HTTP/2 and REST. Cowboy is a small, fast and modern HTTP server for Erlang/OTP. Cowboy aims to provide a complete modern Web stack. This includes HTTP/1.1, HTTP/2, WebSocket, server-sent events and Webmachine-based REST. Cowboy comes with functions for introspection and tracing, enabling developers to know precisely what is happening at any time. Its modular design also easily enables developers to add instrumentation. Cowboy is a high-quality project. It has a small code base, is very efficient (both in latency and memory use) and can easily be embedded in another application. Cowboy is clean Erlang code. It includes hundreds of tests and its code is fully compliant with the Dialyzer. It is also well documented and features a function reference, a user guide and numerous tutorials. Knowledge of the HTTP protocol is recommended but not required, as it will be detailed throughout the guide. -
9
Finage
Finage
Financial data & solutions for everyone. Real-time Stock, Forex and Cryptocurrency market data via API, WebSocket & Widgets. Finage has more than 28.000+ symbols in real-time. We bring together everything that’s required to build financial applications that need Real-Time stock, forex and cryptocurrency data via APIs and WebSocket. You can reach more than 25.000+ U.S. stock data via Finage's Real-Time WebSocket and APIs. You can also use the 15-year Historical Data API for the U.S stocks as well. Finage offers more than 1300+ currencies in real-time & Historical Data API. Forex data all in one place, so you can access our full selection of data. We offer you more than 1500+ cryptocurrencies via API and WebSocket. Finage has the most popular cryptocurrencies as Real-time. Visuality is the best way to demonstrate complex data for easy understanding. Select custom widgets with different color schemes to best fit best on your platform. Available across most of popular platforms.Starting Price: $99 per month -
10
API Tester
API Tester
API Tester is a completely free mobile app available on iOS, Android, macOS, and watchOS. It is a functional API testing tool that allows users to complete compound tasks on any device. - Test any API on the go: REST, GraphQL, WebSocket, SOAP, JSON RPC, XML, HTTP, HTTPS. - GET, POST, PUT, PATCH, DELETE, etc. HTTP request methods are supported. - Perform the API calls with any kind of request data encoding and transfer type. - Import collections from Swagger, Postman, and YAML, or import requests using cURL, as well as export created requests via link or cURL. - Use a powerful GraphQL editor with full-scale experience. - WebSocket testing tool is available: handles connection and message exchange via WS or WSS. The API Tester mobile app allows you to get the job away from your workstation. Save time, work from anywhere!Starting Price: Completely free -
11
OpenMail
OpenMail
OpenMail gives AI agents a dedicated email address. Provision an inbox with one CLI command or API call, each agent gets its own address, not a shared inbox or forwarding alias. Inbound email arrives instantly via webhook or WebSocket, parsed and threaded, with no polling required. Replies land in context so agents can respond without any new interface on the human side. Attachments: PDFs, CSVs, images, spreadsheets, Word documents are automatically converted to LLM-ready text; the agent never touches raw MIME. The API is small by design: one call to provision, standard calls to send, webhooks or WebSocket to receive. Integrates with LangChain, n8n, Make, Vercel AI SDK, and OpenClaw. Custom domains supported. Runs in the EU, GDPR-covered, 99.9% uptime SLA, SOC 2 in progress.Starting Price: 9 EUR -
12
ContextForge MCP Gateway is an open source Model Context Protocol (MCP) gateway, registry, and proxy platform that provides a unified endpoint for AI clients to discover and access tools, resources, prompts, and REST or MCP services in complex AI ecosystems. It sits in front of multiple MCP servers and REST APIs to federate and unify discovery, authentication, rate-limiting, observability, and traffic routing across diverse backends, with support for transports such as HTTP, JSON-RPC, WebSocket, SSE, stdio, and streamable HTTP, and can virtualize legacy APIs as MCP-compliant tools. It includes an optional Admin UI for real-time configuration, monitoring, and log visibility, and is designed to scale from standalone deployments to multi-cluster Kubernetes environments with Redis-backed federation and caching for performance and resilience.
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13
AG-UI
AG-UI
AG-UI is an open, lightweight, event-based protocol that standardizes how AI agents connect to user-facing applications. Built for simplicity and flexibility, it enables seamless integration between AI agents, real-time user context, and user interfaces. AG-UI is designed for agent-human interaction: during agent executions, backends emit events compatible with standard AG-UI event types, and agent backends can accept simple AG-UI-compatible inputs as arguments. It works with any event transport, including SSE, WebSockets, webhooks, and other streaming systems, while providing a flexible middleware layer that ensures compatibility across diverse environments. AG-UI brings agents into user-facing applications and complements the wider agentic protocol stack: MCP gives agents tools, A2A allows agents to communicate with other agents, and AG-UI connects agents directly to the user interface.Starting Price: Free -
14
BlockVigil
BlockVigil
Designed for entrepreneurial software developers, BlockVigil is the ultimate developer tool to build and scale blockchain apps with just a few lines of code. We allow you to build full-stack apps on blockchain, without learning protocol specifics. Smart contracts are quickly deployed through our system and the resulting API is instantly available to start testing. Use webhooks and WebSockets to integrate with third-party services in real-time with minimal technical effort. Our docs cater to every developer, all the way from beginners to advanced. We also provide examples to build upon. Use webhooks, WebSockets and Zapier to execute powerful off-chain and real-world workflows. BlockVigil's API gateway makes it super easy to build your blockchain apps, so you can quickly build and scale with just a few lines of code, from web developers to app developers. -
15
Lucid KV
Lucid KV
Lucid is currently in a development stage but we want to achieve a fast, secure and distributed key-value store accessible through an HTTP API, we also want to propose persistence, encryption, WebSocket streaming, replication and a lot of features. Private Keys Storing, IoT (to collect and save statistics data), Distributed cache, service discovery, distributed configuration, blob storage etc. -
16
Mako Server
Real Time Logic LLC
The Mako Server is a compact, event-driven web and application server designed for resource-constrained systems. Engineered for embedded environments, it combines a lightweight HTTP/HTTPS server with a Lua scripting engine, enabling high-level development with direct access to low-level C code. Its architecture delivers high performance, low memory use, and secure integration, making it ideal for systems that can’t support heavier frameworks but require dynamic web interfaces or APIs. The server supports live updates, built-in debugging, and Lua Server Pages (LSP), offering PHP-like scripting optimized for embedded use. Common use cases include device portals, diagnostic dashboards, REST APIs, and real-time WebSocket interfaces. Lua’s speed and small footprint align perfectly with the Mako Server’s goals. More than just a web server, Mako is a comprehensive framework that enables developers to integrate modern, secure, web-enabled features into compact devices.Starting Price: $498.00 -
17
finlight.me
finlight.me
finlight.me is a powerful, developer-first news API that delivers real-time and historical financial, geopolitical, and market-moving news from a wide range of trusted sources in clean JSON format. It supports advanced querying, including keyword search with boolean operators, date/time filtering, source inclusion/exclusion, language options, sorting, and pagination, enabling precision targeting. The API offers both REST and WebSocket endpoints, the latter providing streaming delivery of new articles matching live queries, complete with sentiment analysis labels and confidence scores. Extended article endpoints include full content and summaries depending on the subscription tier. finlight’s AI-powered sentiment tagging and market-impact insights equip developers with actionable context, while support for WebSocket streaming allows for real-time alerts and deep analytics.Starting Price: $29 per month -
18
GPT‑5.3‑Codex‑Spark
OpenAI
GPT-5.3-Codex-Spark is an ultra-fast coding model designed for real-time collaboration inside Codex. Built as a smaller version of GPT-5.3-Codex, it delivers over 1000 tokens per second when served on low-latency Cerebras hardware. The model is optimized for interactive coding tasks, enabling developers to make targeted edits and see results almost instantly. With a 128k context window, Codex-Spark supports substantial project context while maintaining speed. It focuses on lightweight, precise edits and does not automatically run tests unless prompted. Infrastructure upgrades such as persistent WebSocket connections significantly reduce latency across the full request-response pipeline. Released as a research preview for ChatGPT Pro users, Codex-Spark marks the first milestone in OpenAI’s partnership with Cerebras. -
19
TekSIP
KaplanSoft
TekSIP is a SIP Registrar and SIP Proxy for Windows. TekSIP supports UDP, TCP, TLS and WebSocket (IPv4 & IPv6) transports. TLS and Secure WebSocket are supported in only commercial editions. TekSIP is tested on Microsoft Windows Vista, Windows 7/8/10/11 and Windows 2008-2022 server. TekSIP can be deployed as a signaling server for WebRTC based SIP phones. TekSIP complies with RFC 3261, RFC 3263, RFC 3311, RFC 3581 and RFC 3891. It supports NAT traversal and ENUM. Please see technical details about NAT traversal in Readme. You can select IP address to be listened and alternative SIP endpoints for outgoing calls. You can also log session details into a log file and monitor active registrations and sessions in real-time. You can monitor number of active registrations and sessions using Windows Performance Monitor (Perfmon.exe). TekSIP can redirect calls to alternate endpoint when called endpoint is unavailable (Off-line, busy...). Active SIP session can be terminated via GUI.Starting Price: $239 -
20
EODHD
EODHD
EODHD is a financial data API platform that provides developers and analysts with access to a comprehensive range of global market data through a single, unified interface. It offers over 30 years of historical data along with real-time and intraday feeds across more than 60 stock exchanges, covering over 150,000 tickers, including stocks, ETFs, mutual funds, bonds, Forex pairs, and digital currencies. It delivers multiple types of datasets such as end-of-day prices, live OHLCV data, corporate actions like splits and dividends, financial news, technical indicators, macroeconomic data, and stock screeners, all accessible via REST APIs and WebSocket connections. It delivers multiple types of datasets such as end-of-day prices, live OHLCV data, corporate actions like splits and dividends, financial news, technical indicators, macroeconomic data, and stock screeners, all accessible via REST APIs and WebSocket connections.Starting Price: $19.99 per month -
21
OpenAgents
OpenAgents
OpenAgents is an open source framework and platform for building, connecting, and deploying networks of AI agents that can discover, communicate, collaborate, and solve problems together rather than operating in isolation, enabling developers to launch and join agent communities that work at scale and share resources seamlessly. It provides infrastructure for AI agent networks where each network acts as a self-contained community with peer discovery, message passing, and coordinated collaboration over flexible protocols such as HTTP, WebSocket, and gRPC, and is designed to be protocol-agnostic and compatible with popular large language model providers and agent frameworks to support diverse deployment scenarios. Users can build their own agents with simple configurations or integrate custom logic and tools, connect them to one or more networks, and manage interactions using OpenAgents’ standard interfaces.Starting Price: Free -
22
AliwareMQ for IoT
Alibaba Cloud
AliwareMQ for IoT is a message service that is designed specifically for IoT and mobile Internet (MI). The service can be applied to multiple scenarios, including live streaming, financial payments, smart catering, instant messaging, mobile apps, smart devices, and Internet of Vehicles. Message Queue for MQTT supports multiple protocols including MQTT and WebSocket to enable two-way communications between devices and the cloud. In this way, messages can be exchanged in multiple business models including C2C, C2B, and B2C to achieve Internet of Everything. -
23
Inworld Realtime STT
Inworld
Inworld Realtime STT is a realtime streaming STT API that understands users beyond their words. It combines low-latency speech recognition with voice profiling, extracting emotion, vocal style, accent, age, and pitch directly from raw audio so downstream LLMs and TTS systems can respond with more adaptive, expressive behavior. Developers can stream audio in real time, transcribe complete files, or extract voice profile signals through one unified API, with realtime bidirectional streaming over WebSocket, synchronous transcription for full audio files, voice profile signals on every streaming chunk, and multi-provider support through a single model ID. Every audio chunk can produce a realtime profile of the speaker with confidence scores, giving LLMs structured context such as whether a user sounds sad, frustrated, soft, high-pitched, or calm.Starting Price: Free -
24
Apache Tomcat
Apache
The Apache Tomcat® software is an open source implementation of the Jakarta Servlet, Jakarta Server Pages, Jakarta Expression Language, Jakarta WebSocket, Jakarta Annotations and Jakarta Authentication specifications. These specifications are part of the Jakarta EE platform. Apache Tomcat software powers numerous large-scale, mission-critical web applications across a diverse range of industries and organizations. Some of these users and their stories are listed on the PoweredBy wiki page. The Apache Tomcat Project is proud to announce the release of version 10.0.10 of Apache Tomcat. This release implements specifications that are part of the Jakarta EE 9 platform. -
25
CCXT Pro
CCXT Pro
CCXT Pro is a professional tool for algorithmic crypto-trading. It is a high-performance superset of the CCXT library, one of the world's leading open-source frameworks for crypto finance. CCXT Pro includes the standard CCXT library and wraps it with powerful new features and useful enhancements. Unified public and private WebSockets APIs. Efficiency, higher speeds, and lower latencies. Less traffic, fewer bandwidth requirements. Priority in development and maintenance. Dedicated and responsive technical support. Backward compatibility with CCXT.Starting Price: $29 per month -
26
Yaak
Yaak
Yaak is a fast, lightweight, and privacy-focused desktop API client designed for developers to test, debug, and interact with APIs in a clean and efficient environment without relying on cloud services. It works entirely offline, storing all data locally on the user’s machine with encrypted secrets and zero telemetry, ensuring full control over sensitive information and eliminating the need for accounts or external servers. It supports a wide range of protocols, including REST, GraphQL, gRPC, WebSockets, and Server-Sent Events, allowing developers to work with different types of APIs in a single interface. It includes features such as dynamic request templating with variables and functions, request chaining, and full debugging tools for inspecting headers, cookies, payloads, and responses. Yaak also integrates with Git by storing workspaces as plain files, enabling version control and collaboration while maintaining security through encrypted data handling.Starting Price: $79 per year -
27
Eclipse Jetty
Eclipse Foundation
Jetty provides a web server and servlet container, additionally providing support for HTTP/2, WebSocket, OSGi, JMX, JNDI, JAAS and many other integrations. These components are open source and are freely available for commercial use and distribution. Jetty is used in a wide variety of projects and products, both in development and production. Jetty has long been loved by developers due to its long history of being easily embedded in devices, tools, frameworks, application servers, and modern cloud services. Full-featured and standards-based. Open source and commercially usable, flexible and extensible, small footprint, embeddable, asynchronous, enterprise scalable, and dual-licensed under Apache and Eclipse. Large clusters, such as Facebook Presto. Cloud computing, such as Google AppEngine. With the direction of Java and the JakartaEE project (formerly JavaEE) in 2020, the current recommended version of Jetty for use depends upon the servlet API version, desired licensing, etc. -
28
MaticVigil
MaticVigil
We allow you to build full-stack apps on Ethereum via Matic Network, without learning protocol specifics. Our docs cater to every developer, all the way from beginners to those already building apps via web3, and provide examples to build upon. Smart contracts are quickly deployed through our system and the resulting Open API spec along with webhook and WebSockets are instantly available to start testing. Supercharge and extend your blockchain apps with our integration services over Websockets, Webhooks, Zapier, Slack, IFTTT. The possibilities are endless. MaticVigil is an API gateway on top of the Matic-network EVM-compatible sidechain. It enables a developer to write code to interact with value transfers and transactions on Matic as if it were talking to just another web service REST API over HTTP. You can focus on coding "business logic" without worrying about the "protocol logic" behind the scenes. -
29
Artillery
Artillery
Artillery is a full-stack performance and reliability testing platform that helps teams keep apps fast and reliable with load testing, scalable Playwright E2E testing, and production monitoring in one toolkit. It is modern, powerful, easy to use, incrementally adoptable, and built to work with coding agents. Engineering teams use Artillery to test and optimize applications so they stay performant and resilient under high load, testing everything from APIs to full browser experiences with the same TypeScript and JavaScript skills they already have. Artillery supports HTTP APIs, WebSocket and Socket.io services, SOAP, GraphQL, and complex web apps with real browsers. It includes built-in distributed load testing, allowing teams to run cloud-scale, multi-region tests on AWS Lambda, AWS Fargate, or Azure Container Instances without setting up or managing infrastructure.Starting Price: $199 per month -
30
Tornado Web Server
Tornado
Tornado is a Python web framework and asynchronous networking library, originally developed at FriendFeed. By using non-blocking network I/O, Tornado can scale to tens of thousands of open connections, making it ideal for long polling, WebSockets, and other applications that require a long-lived connection to each user. Tornado is different from most Python web frameworks. It is not based on WSGI, and it is typically run with only one thread per process. While some support of WSGI is available in the tornado.wsgi module, it is not a focus of development and most applications should be written to use Tornado’s own interfaces (such as tornado.web) directly instead of using WSGI. In general, Tornado code is not thread-safe. Tornado is integrated with the standard library asyncio module and shares the same event loop (by default since Tornado 5.0). In general, libraries designed for use with asyncio can be mixed freely with Tornado. -
31
PENDAX
Compendium
A Javascript library allowing simplified interaction with advanced commands on a growing list of cryptocurrency exchanges and financial applications. Simplified exchange commands and interoperability. Our underlying high-frequency trading engine, PENDAX, is available for all developers, traders, financial analysts, and data scientists to build custom integrations on. It provides simple access to a variety of different use cases revolving around trading and data deployments. Current Feature Summary - Full Public and Private HTTP REST APIs for all supported platforms are integrated in an efficient manner for secondary deployment. - Aggregated commands are normalized between systems in the unified package making PENDAX extremely easy to integrate. - WebSocket and live data capabilities are included for all supported exchanges. - No subscription is needed for a "Professional" version of PENDAX.Starting Price: Free -
32
Infura
Infura
Infura's world-class infrastructure will ensure your decentralized application scales to meet your user demand. Connect your app immediately with our instant access APIs. We support JSON-RPC over HTTPS & WebSocket interfaces, providing request and subscription-based connections. Start using Infura with a single URL. Our 24/7 team of experts is ready to handle all network changes and upgrades so you can focus on building your applications. We believe in a future powered by decentralized networks and protocols. We provide world-class infrastructure for developers so you can spend your time building and creating. You can find valuable insights, add applications, and more through our Infura dashboard. Need help or have questions? Get answers in our active community, up-to-date status page, or dig directly into our expanding library of documentation.Starting Price: $50 per month -
33
CloudMQTT
CloudMQTT
CloudMQTT is a perfect solution for "Internet of Things" messaging between low-power sensors or mobile devices such as phones, embedded computers, or microcontrollers like the Arduino. CloudMQTT automates every part of the setup and running of your hosted mosquitto message broker. Let your team focus on what they do best - building your product. Leave server management and monitoring to the experts. Use CloudMQTT WebSocket client to view messages pushed from your device to the browser or publish messages from the browser to your device. This is ideal for testing and debugging since you can display live information from a device or sensor in real-time. Invite your co-workers and you will separate CloudMQTT accounts, but manage the same set of instances. You decide where to send notifications and who pays the bills.Starting Price: $5 per month -
34
SpeedyNodes
SpeedyNodes
SpeedyNodes is a service that blockchains companies and privates in an easy way to access nodes by JSON-RPC, HTTPS & WebSockets APIs. SpeedyNodes is a node provider that provides the infrastructure for building on blockchain. At SpeedyNodes we do provide reliable full, dedicated and Archive blockchain nodes. With our lightning-fast API, providing instant access to Ethereum, Polygon, Bitcoin, Binance and much more. Our service is very fast and responsive. Our positive feedback is very good . We are trying to get everyone onboard with our affordable prices. Our prices start from $50 with unlimited requests.Starting Price: $50 -
35
SurrealDB
SurrealDB
SurrealDB offers a dynamic and adaptable platform for business. With an integrated suite of cutting-edge database solutions, tools, and services, SurrealDB empowers your workforce to discover innovative answers using products meticulously crafted to meet their requirements. The query language in SurrealDB looks and works similarly to traditional-SQL, but allows for querying over time-series and connected graph data. SurrealQL is an advanced query language, with programming language functionality, that allows developers or data analysts to work with SurrealDB in the ways they choose. Connect directly to SurrealDB from any end-user client device. Run SurrealQL queries directly within web-browsers, ensuring that users can only view or modify the data that they are allowed to access. Highly-performant WebSocket connections allow for efficient bi-directional queries, responses and notifications. -
36
Specmatic
Specmatic
Specmatic offers a no-code, specification-driven, visual approach to API testing by leveraging API specifications to automatically execute positive and negative tests. Specmatic Studio offers broad format and protocol support across REST, SOAP, GraphQL, gRPC, WebSockets, and asynchronous messaging systems (message queues and event-driven APIs). The platform provides a comprehensive toolkit for API development and testing, utilizing specs as the single source of truth. Key features include: • Contract testing across various protocols • Service virtualization and mocking • Workflow and resiliency testing • Backward compatibility checks to prevent breaking changes • Open-source testing tools for OpenAPI, MCP and SOAP • Postman collection import for spec creation Specmatic focuses on functional correctness, contract compliance, resiliency, and compatibility testing. Genie assists API design, enabling interactive validation of the API spec prior to generating an MCP server.Starting Price: $2500 per month (50 seats) -
37
Massive
Massive
Massive is a market-data infrastructure platform built to provide real-time and historical financial data to developers, startups, and trading firms. It delivers institutional-grade market data across stocks, options, indices, currencies, and futures, all via a streamlined API, WebSocket, flat-file S3 access, or SQL query interface. The platform emphasizes low latency, direct connectivity to major exchanges (NYSE, NASDAQ, CBOE, OTC), and data normalization to eliminate survivorship bias and outdated pipelines. Massive positions itself as “modernizing Wall Street” by removing legacy bottlenecks and providing the same quality of market data typically reserved for large institutions, but now accessible to any app builder. The platform also includes extensive documentation, client libraries in Python, JavaScript, Go, and Java, tutorials, and example projects to accelerate integration.Starting Price: $29 per month -
38
Barchart OnDemand
Barchart
Our flexible cloud-based APIs make getting powerful data into your applications, workflows, and products simple. Through Amazon Web Services we maintain multiple data centers throughout the United States, ensuring optimal reliability and redundancy. Through server virtualization and built-in security procedures we can scale up our institutional ready services in a matter of seconds. We support both GET and POST requests as well as SOAP. Data can be delivered in multiple formats including XML, JSON and CSV, and can be streamed over WebSockets. We’re compatible with any operating system, such as Windows, Linux, iOS or Android, and any programming language, such as Python, Java, PHP, R, or ASP.NET. We embrace the cloud but also maintain physical data centers for specific client needs. Through our Equinix-based facilities we cater to low latency requirements and provide a true physical back-up. -
39
Layercode
Layercode
Layercode is a cloud-based developer platform that makes it easy to build production-ready, low-latency voice AI agents by handling the real-time infrastructure so you can focus on your agent’s logic; it manages WebSockets, voice activity detection, global edge deployment, and voice model integrations while giving you full control over how your agent thinks, speaks, and responds. It enables natural, fluid voice conversations with sub-second response times and human-like turn-taking, offers observability tools so you can inspect calls, latency, and failures in production, and fits naturally into modern TypeScript and Next.js stacks with simple CLI and SDK support so you can receive text and send text back. With Layercode, you can avoid vendor lock-in by hot-swapping leading voice and transcription model providers, maintain complete flexibility by plugging in your own AI agent backend, and deploy voice agents across web, mobile, and phone interfaces.Starting Price: $0.04 per minute -
40
Check24-7.in
Check24-7.in
With the 24-7Connect interface you enable us to communicate with your PMS data. Web sockets can also be used instead of webhooks. The web socket protocol is used for the transport, the interface remains unchanged. -
41
HarperDB
HarperDB
HarperDB is a distributed systems platform that combines database, caching, application, and streaming functions into a single technology. With it, you can start delivering global-scale back-end services with less effort, higher performance, and lower cost than ever before. Deploy user-programmed applications and pre-built add-ons on top of the data they depend on for a high throughput, ultra-low latency back end. Lightning-fast distributed database delivers orders of magnitude more throughput per second than popular NoSQL alternatives while providing limitless horizontal scale. Native real-time pub/sub communication and data processing via MQTT, WebSocket, and HTTP interfaces. HarperDB delivers powerful data-in-motion capabilities without layering in additional services like Kafka. Focus on features that move your business forward, not fighting complex infrastructure. You can't change the speed of light, but you can put less light between your users and their data.Starting Price: Free -
42
Agoston.io
Agoston.io
Get instant access to a self-generated GraphQL server. The backend automatically discovers your data model. Enjoy a comfortable development experience with a hot refresh on database changes. There is no limit to your needs for simple/complex queries or function calls. GraphQL is faster than other communication APIs because it removes over-fetching and under-fetching problems. It also comes with a WebSocket under the hood: subscribe to data-specific modifications in the database and offer exceptional real-time customer experience to your user. The proven permission system from Postgres offers the flexibility to allow operations from tables to specific columns and rows. Agoston relies on this robust permission system to guarantee access to data. Users only access what they are allowed to.Starting Price: $49 per month -
43
Ably
Ably
Ably is the definitive realtime experience platform. We power more WebSocket connections than any other pub/sub platform, serving over a billion devices monthly. Businesses like HubSpot, NASCAR and Webflow trust us to power their critical applications - reliably, securely and at serious scale. Ably’s products place composable realtime in the hands of developers. Simple APIs and SDKs for every tech stack, enable the creation of a host of live experiences - including chat, collaboration, notifications, broadcast and fan engagement. All powered by our scalable infrastructure.Starting Price: $49.99/month -
44
RoboTask
RoboTask
RoboTask is a macro automation software that can easily automate any series of tasks without writing code. The program allows to easily create simple macros, as well as highly complex automation, involving conditional logic, loops, custom variables, and other advanced options. Automation of work with files and folders; keyboard and mouse macro recorder. Emulation of mouse and keyboard actions and automated FTP/SFTP/FTPS file transfer (upload, download, synchronize). Email POP3/IMAP/SMTP automation (checking, sending and retrieving), SQL database automation, it works with Excel. Web automation (fill web forms, web actions). Working with images (convert, resize, crop, flip, watermark, etc.) and working with a clipboard, system registry, processes, regular expressions, etc. Built-in HTTP web server with WebSockets support. integration with Python, Javascript, Powershell, and much more! You can create a scheduled macro that runs one or more tasks at specified times.Starting Price: $150 one-time payment -
45
CoinAPI
CoinAPI
All cryptocurrency exchanges integrated under a single API. CoinAPI is a platform which provides fast, reliable and unified data APIs to cryptocurrency markets. We are a high-quality, one-stop-solution market data provider for cryptocurrency markets. All CoinAPI data is standardized. Market symbol details and asset codes are double-checked by real humans to ensure maximum quality. Our data is delivered to you on-demand using well-documented and simple HTTP RESTful API in JSON, XML or CSV formats. For more demanding integrations requiring real-time market data streaming, we have access through WebSocket and FIX protocols. We provide helper libraries for the most popular programming languages, so you can focus on the most important aspects instead of wasting time connecting the pieces together. We provide helper libraries for the most popular programming languages, so you can focus on the most important aspects instead of wasting time connecting the pieces together.Starting Price: $79 per month -
46
Bitstamp
Bitstamp
With a proven track record and a mature approach to the industry, we provide reliable trading of cryptocurrencies. Stay connected to the market with our mobile app. Featuring advanced order types and analytical tools for experienced traders, as well as a simple buy & sell interface for those just getting started. We provide premium access to crypto trading for both individuals and institutions through high liquidity, reliable order execution and constant uptime. Set up your own trading interface or deploy your algorithmic strategy with our high-performance FIX and HTTP APIs. Connect to our WebSocket for real-time data streaming. Premium 24/7 support available to all customers worldwide by phone or email. Dedicated account managers for partners. Instant card purchases are supported worldwide with a few exceptions. Deposit and withdraw funds easily from anywhere in the world. US customers can use ACH for instant deposits. -
47
gpt-4o-mini Realtime
OpenAI
The gpt-4o-mini-realtime-preview model is a compact, lower-cost, realtime variant of GPT-4o designed to power speech and text interactions with low latency. It supports both text and audio inputs and outputs, enabling “speech in, speech out” conversational experiences via a persistent WebSocket or WebRTC connection. Unlike larger GPT-4o models, it currently does not support image or structured output modalities, focusing strictly on real-time voice/text use cases. Developers can open a real-time session via the /realtime/sessions endpoint to obtain an ephemeral key, then stream user audio (or text) and receive responses in real time over the same connection. The model is part of the early preview family (version 2024-12-17), intended primarily for testing and feedback rather than full production loads. Usage is subject to rate limits and may evolve during the preview period. Because it is multimodal in audio/text only, it enables use cases such as conversational voice agents.Starting Price: $0.60 per input -
48
Kamailio
Kamailio
Kamailio® (successor of former OpenSER and SER) is an open-source SIP server released under GPLv2+, able to handle thousands of call setups per second. Kamailio can be used to build large platforms for VoIP and real-time communications, presence, WebRTC, Instant messaging, and other applications. Moreover, it can be easily used for scaling up SIP-to-PSTN gateways, PBX systems, or media servers like Asterisk™, FreeSWITCH™, or SEMS. Among the powerful features, are asynchronous TCP, UDP and SCTP, secure communication via TLS for VoIP (voice, video, text); WebSocket support for WebRTC; IPv4 and IPv6; simple instant messaging and presence with embedded XCAP server and MSRP relay; asynchronous operations; IMS extensions for VoLTE; ENUM; DID and least cost routing; load balancing; routing fail-over; accounting, authentication and authorization; support for many backend systems such as MySQL, Postgres, Oracle, Radius, LDAP, Redis, Cassandra, MongoDB, Memcached. -
49
Graffle
Graffle
Our thin layer over the Flow blockchain allows you to read, write, and query the blockchain using any language. Our indexers monitor the chain 24/7, store your events, and execute cadence at scale. Subset of tools and infrastructure to enhance non-fungible tokens with real-world utility. Emitting events to the chain with push guarantees, queuing and deferred execution. Setup an indexer and instantly get real-time streaming data directly to your webhook or WebSocket. Drill down into events and statistics around your traffic, webhooks, and APIs. We are actively looking for beta testers. Build a new dApp with Graffle. Aggregate at scale, gain insight, join our beta wait list today! -
50
Proxyman
Proxyman LLC
## Features * 🍏 **macOS-optimized:** Crafted with Swift and Objective-C, leveraging Apple SwiftNIO for high-performance networking. * 🖥️ **Apple Silicon ready:** Full compatibility with M1, M2, and M3 chips. * 🚀 **Modern OS support:** Designed for macOS Ventura and Sonoma. * 🌐 **Seamless traffic interception:** Effortlessly capture HTTP/HTTPS and WebSocket data from browsers, iOS, and Android. * 🎨 **User-friendly interface:** Sleek and intuitive design for ease of use. * 🔎 **Advanced filtering:** Multiple options for precise data analysis. * 📱 **Cross-platform setup:** Detailed guides for iOS simulator and physical iOS/Android devices. * 🛠️ **Essential debugging toolkit:** Compose, Repeat, Wildcard/Regex Filtering, Column Customization, and more. * 🔧 **Pro-level features:** Breakpoints, Local/Remote Mapping, Blacklisting. ...Starting Price: 69$
