gRPC Swagger

gRPC Swagger is a free, open-source debugging tool for discovering and calling gRPC methods through Swagger UI. It uses gRPC reflection to find services and display method definitions and parameters. To connect a service, register its host and port; the tool then scans for available services. Calls can be made with Swagger UI’s “Try it out” control, using JSON-formatted request data and headers. The gRPC service must have reflection enabled, though the setup instructions say proto files and related implementations need no changes. The project can run from a released JAR or be built from source, and defaults to port 8080. Configuration can control whether registered services are listed and how long an inactive registration remains before expiration. Its documented API includes service registration, service listing, method calls, and Swagger UI documentation. The software is self-hosted and available under the MIT License. The releases page lists version 0.1.8 as the latest release, described as fixing duplicate services after registration.

gRPC Swagger provides a focused interface for discovering and exercising reflected gRPC services. Reflection must be enabled on the service for discovery to work.

This tool suits developers who need to inspect or call gRPC methods through Swagger UI. It requires a gRPC service with reflection enabled.

gRPC Swagger is a self-hosted debugging utility that turns reflected gRPC services into an interactive Swagger UI. It is best for developers who control a service and want to inspect its methods and make browser-based calls. Its focused workflow is worthwhile when reflection is available, but that prerequisite rules out services that cannot expose it.

Overview

Register a gRPC endpoint with its host and port, and the application scans for services exposed by that endpoint. Swagger UI presents each method’s definition and parameters, then offers a “Try it out” control for making a call. Request bodies and headers use JSON; the headers are forwarded to the server as gRPC metadata.

This creates a short path from service discovery to an actual diagnostic request without changing proto files or their related implementations. It is a practical fit for development and troubleshooting, while teams that cannot enable server reflection need another approach.

Key features

• Reflection-based discovery: The endpoint registration and scan are driven by gRPC reflection, so definitions stay tied to what the running service exposes. The benefit is avoiding a separate catalog to maintain; the cost is that discovery fails when reflection is disabled.
• Swagger UI exploration: Method and parameter definitions are visible in a familiar API-documentation interface. “Try it out” turns that reference into a test call, which is more direct than constructing every request in a separate client.
• JSON requests and metadata: Supplying request data and headers as JSON gives calls a consistent input format. Headers become gRPC metadata, allowing diagnostic calls that need those values without leaving the interface.
• Service lifecycle controls: Configuration can allow or prevent listing registered services and can expire an inactive registration after a chosen number of seconds. Those controls help limit stale entries in a shared debugging setup.
• Documented API: Endpoints cover service registration, service listing, method invocation, and Swagger UI documentation. That makes the tool usable as a component in workflows that need more than the browser screen.
• Flexible deployment: Run a released JAR or build from source; the default port is 8080. This suits teams that prefer a packaged self-hosted utility as well as those that need to compile their own deployment.

Pricing

Open source — free: The MIT-licensed software has no paid plan, trial period, seat charge, or usage fee. The license permits use without charge subject to its stated conditions. A free, self-hosted distribution is a strong match for individual developers and teams comfortable operating their own debugging service; it does not provide a hosted option that removes deployment responsibility.

Platforms

gRPC Swagger is offered for API, web, and self-hosted use. The JAR and source-build options support deployment in an environment you control, with Swagger UI supplying the browser-facing interface. It is not presented as a native desktop application.

Who it's for

This is aimed at gRPC developers, QA engineers, and operators who need to inspect reflected services and issue controlled calls during development or troubleshooting. It is especially suitable when proto and implementation files should remain untouched and a browser workflow is preferable. It is a poor choice for services where reflection cannot be enabled, or for users seeking a managed SaaS rather than a self-hosted deployment.

Pros and cons

Pros

• Direct discovery: Reflection exposes live service and method definitions without maintaining parallel descriptions.
• Calls from the documentation view: “Try it out” keeps inspection and invocation in one interface.
• Useful metadata handling: JSON headers are passed through as gRPC metadata for requests that require them.
• No license cost: MIT licensing and a $0 plan remove purchase and seat-budget barriers.
• Operational controls: Listing and inactivity-expiration settings help manage registered endpoints.

Cons

• Reflection is mandatory: Services that do not expose reflection cannot be discovered through the tool.
• Self-hosting is required: You must run the JAR or build and operate the application yourself.
• Browser calls depend on JSON: Users wanting another request or metadata format have no documented alternative in this product.

Alternatives

For a broader directory of related utilities, browse gRPC Tools.

• Chiko is a free MIT-licensed option; choose it when its general-purpose workflow suits you better than reflection-driven Swagger calls.
• ghz is an open-source gRPC load-testing CLI and Go package for API, Linux, and self-hosted use; pick it when load testing matters more than browser documentation.
• gRPC CLI runs on Linux, macOS, and Windows for unary RPC calls; choose it when a command-line client and broad desktop OS coverage are priorities.
• grpcmock-go provides open-source Go testing utilities; it is the better fit for mocking and test construction.
• Kreya offers a free plan for individuals with request history limited to the latest request; choose it for a desktop-oriented alternative with a free trial.
• protoc-gen-doc generates documentation from protobuf definitions; pick it when static documentation, rather than live reflected calls, is the goal.
• sabledocs is an open-source static generator requiring Python 3.11+ and a Protobuf descriptor file; choose it for descriptor-based documentation output.
• Bandura has a free plan with no account or feature tiers and a separate $59 one-time commercial licence; it suits readers comparing licensing choices beyond this MIT project.

Verdict

Choose gRPC Swagger if you control reflected gRPC services and want a free, self-hosted route from endpoint registration to documented browser calls. Its main reason to look elsewhere is equally clear: without server reflection, it cannot discover what you need to debug.