Restbed: asynchronous C++ HTTP framework with WebSockets, SSE, and TLS support

Restbed targets C++ applications that need HTTP handling without a separate server process

The project's stated goal is to bring asynchronous RESTful functionality to C++ applications directly, which is a different approach from placing a C++ backend behind nginx or Apache and connecting them through a socket or CGI mechanism. An application built on Restbed listens for HTTP connections itself, handles request routing, and sends responses, all within the same native process.

The README quotes a Solutions Architect from Bellrock Technology: "It's akin to embedding NGINX into your companies own product line." That analogy captures the architectural intent, though it is one user's description rather than a measured claim. The value is that teams writing embedded software, device firmware, or self-contained desktop utilities can expose an HTTP interface without shipping a separate server alongside their binary.

The README lists deployment targets as mobile, tablet, desktop, and embedded environments, alongside a stated enterprise-class positioning. Those two ends of the spectrum suggest the framework was designed with portability and a small runtime footprint in mind, though the README does not document minimum OS versions or compiler requirements.

Version 5.0.0 LTS in 2026 followed a nearly five-year gap from 4.8

The release history in the repository shows three releases: version 4.7 on 2020-04-01, version 4.8 on 2021-08-24, and version 5.0.0 on 2026-04-06. The 4.8 release is described in the release notes as Unix Domain sockets, assorted bug fixes, and dependency updates. Version 5.0.0 is labeled as LTS, indicating it is a Long Term Support release.

The gap between 4.8 and 5.0.0 is roughly four and a half years. For a project that jumped from minor to major version during that interval, the 5.0.0 release likely carries architectural changes, though the release notes visible in the repository only give the LTS designation without detailing what changed. The changelog.txt file at the repository root would be where the full change record lives.

The last push to the repository was on 2026-06-23, and the repository is not archived. The LTS label on the current release suggests the project intends to provide a stable target for teams that pin versions for extended periods.

WebSockets, Server-Sent Events, and Comet represent three distinct push models

Three entries in the feature table address server-to-client communication, each with a different protocol model.

WebSockets provide full-duplex communication over a single TCP connection: both client and server can send data at any time without a new request. Server-Sent Events enable one-way streaming from server to client, specifically for text-based event data, which the README describes as suited to real-time notifications or updates generated on the server. Comet is the long-polling model, where the server holds an HTTP connection open until it has data to push, then responds and the client immediately opens another connection.

Having all three in one framework gives a C++ application the ability to choose the push mechanism that fits the client environment. WebSockets require a client-side WebSocket library. Server-Sent Events work with the browser's native EventSource API without additional JavaScript. Long polling works with any HTTP client that can hold a connection open, including older clients that do not support WebSockets.

The feature table in the README links each of these to an example document under docs/example/ in the repository, so there are concrete code samples to consult before committing to any of them.

SSL/TLS, HTTP Pipelining, path parameters, compression, and custom methods are in the feature table

Beyond the push models, the visible portion of the feature table covers several other capabilities.

SSL/TLS handles secure communication, which the README describes as transmitting private data online. HTTP Pipelining allows multiple HTTP requests to be sent on a single TCP connection without waiting for each response before sending the next, a technique that reduces round-trip overhead on high-latency connections.

Path parameters let you annotate URIs with identifiers such as resource keys and revision numbers, which is the standard pattern for REST resource addressing. Query parameters are handled automatically through built-in parsing rather than manual string splitting. Multi-path resources let a single resource handler respond to more than one URI path, which the README says improves readability.

Compression support covers GZip and Deflate according to the README, though the description says it adapts to any compression form. Customizable HTTP methods allow adding verbs beyond the standard set. Logging is customizable at the output destination and format. The README table is truncated in the repository at the Encoding row, so there may be additional features not visible here.

The build system is Autotools; the docs/ directory holds the installation guide

The top-level repository layout contains configure.ac, Makefile.am, and autogen.sh, which are the three primary files of an Autotools build. There is also a restbed.pc.in file, which indicates the build generates a pkg-config descriptor that downstream projects can use to locate the library and its compiler flags.

The README does not reproduce build or installation commands. Documentation is in the docs/ directory, which the feature table links to for each example, including an HTTPS_SERVICE example under docs/example/HTTPS_SERVICE.md that covers TLS configuration. The legal/ directory contains additional licensing documents beyond the LICENSE file at the root.

For teams that use vcpkg or Conan to manage C++ dependencies, neither package manager is mentioned in the README, so availability through those channels is not confirmed by the repository material and would need to be verified separately. The homepage listed in the repository metadata is http://www.corvusoft.co.uk.

Custom license and a company domain suggest terms differ from Apache or MIT

GitHub classifies Restbed's license as Other because it does not match a recognized open-source template. The LICENSE file at the repository root contains the actual terms, and the legal/ directory holds additional documents. Anyone distributing a product that embeds Restbed, or shipping a modified version, needs to read those files in full.

The copyright.txt file at the repository root is a second document worth checking alongside LICENSE. The project's homepage points to corvusoft.co.uk, which is a company domain. That combination, a custom license and a commercial company behind the project, is consistent with a dual-licensing model where open-source use under one set of terms and commercial use under another are both available. The README does not state this explicitly, so the actual licensing structure requires reading the LICENSE and legal/ documents, not inferring it from the project structure.

When the asynchronous session model adds complexity you do not need

Restbed's asynchronous design is appropriate when the application needs to handle many concurrent HTTP connections without blocking threads. For a C++ program that handles one or a handful of simultaneous API calls, that model introduces a session-management layer that a simpler synchronous library would not require.

Boost.Beast is the most common alternative in the C++ ecosystem for HTTP and WebSocket handling. It operates at a lower level than Restbed, closer to the raw Boost.Asio I/O layer, and gives the programmer explicit control over connection handling, SSL contexts, and message parsing. The tradeoff is substantially more boilerplate per endpoint: you compose the protocol behavior yourself rather than registering resource handlers and letting the framework manage sessions.

For teams already using Boost.Asio elsewhere in a codebase, Boost.Beast is the natural fit because it shares the same executor model. For teams that want a resource-routing abstraction with fewer lines of setup per endpoint, Restbed's model is closer to a typical web framework. The gap between the two is the gap between a toolkit and a framework: more control in Boost.Beast, less setup code in Restbed.

Editorial conclusion

Restbed fits C++ projects that need to expose an HTTP API or handle WebSocket connections from within a native binary, without routing traffic through a separate server process. Skip it when a custom-licensed C++ dependency is a procurement concern, or when you need a synchronous request-response model without asynchronous session management. Before adopting v5.0.0 LTS, confirm the license terms in LICENSE are compatible with your distribution requirements, and check docs/ for platform details, since the README names mobile, tablet, desktop, and embedded as targets but does not give minimum OS or compiler versions.

Frequently asked questions

Official sources

1. Corvusoft/restbed on GitHub
2. Issues
3. Project website
4. README
5. Releases