GripMock

Overview

GripMock is aimed at developers who need to exercise gRPC clients without depending on a live service. Its standout advantage is control over varied and streaming responses; the trade-off is a self-hosted setup that your team must run and maintain.

It suits development and automated tests more than teams seeking a hosted mock service or a graphical client for making ad hoc calls.

Key features

Shape requests and responses

Rules can match request values and headers using equality, partial matches, regular expressions, globs, or any-of conditions, with priorities for overlapping stubs. That flexibility makes it practical to cover multiple client paths with one mock server. Dynamic templates can draw on request data, headers, and stream position, while status errors and delays help exercise error handling and timeout behavior.

Streaming and live editing

GripMock handles unary, server-streaming, client-streaming, and bidirectional gRPC calls, a useful breadth for services whose behavior cannot be represented by a single request and reply. The dashboard can show loaded, matched, used, and unused stubs, and lets developers create, change, or remove them while the server is running. Those controls speed iteration, but do not eliminate the work of managing the server and its stub definitions.

Service definitions and integrations

It accepts .proto files and compiled .pb descriptors, including descriptors supplied to a running server without restarting it. It can also start from a Buf Schema Registry module reference. Docker, Homebrew, release binaries, shell script, and Go installation give teams several ways to fit it into their environment; an embedded Go SDK avoids a separate container or binary in Go tests. An official GitHub Actions guide supports CI use.

gRPC-Web and server reflection extend its reach beyond basic gRPC calls. Native TLS and optional mutual TLS address encrypted connections and client-certificate authentication. OTLP trace export and a Prometheus-scrapable /metrics endpoint help teams observe the mock server. MCP endpoints also enable AI agents and tool-driven automation, though their value depends on whether those workflows are part of a team's toolchain.

Pricing

GripMock is free and open source under the MIT License, with no paid tiers described. That makes it accessible for personal, commercial, and CI use without a per-seat price, while leaving deployment and operational responsibility with the user. The project directs bug reports and questions to GitHub issues.

Platforms

GripMock is self-hosted and supports Linux, macOS, and Windows, with API and web interfaces. Docker, native installation routes, and the in-process Go SDK provide different deployment options; it is not a hosted service that removes server administration.

Who it's for

Choose GripMock if you build gRPC clients or services and need repeatable tests for request variations, streaming behavior, failures, or timeouts. It is especially suitable for local development, CI, and containerized test environments, and the Go SDK is a strong fit for Go test suites. Look elsewhere if you want a managed service or primarily need a desktop tool for manually sending gRPC requests.

Pros and cons

• Pros: Flexible matching and dynamic responses support realistic scenario coverage without a backend.
• Pros: All four gRPC call patterns, including bidirectional streaming, are supported.
• Pros: Live stub editing, descriptor loading, and multiple installation paths suit iterative development and CI.
• Cons: Self-hosting means users must operate the server and integrate it into their own environments.
• Cons: The Go SDK's in-process convenience is specific to Go tests; other environments need a separate deployment.

Alternatives

For more options, browse gRPC Tools.

• Bandura is another free option for Linux, macOS, Windows, and self-hosted use; choose it if you want an alternative gRPC tool with a commercial licence option.
• BloomRPC Extended is free on Linux, macOS, and Windows; consider it if you want a desktop alternative.
• FintX has a free open-source plan with unlimited gRPC clients, saved requests, tabs per method, and projects; choose it for a client-oriented workflow rather than GripMock's mock-server focus.
• grpcui is a free, MIT-licensed option available on Linux, macOS, Windows, self-hosted, and web; consider it when you want a different open-source gRPC tool.
• Kreya has a free individual plan, limited to the latest request in its history, and a free trial; choose it if a client application suits your workflow better than a mock server.
• Evans is a free open-source gRPC client for Linux, macOS, and Windows; pick it when you need a client rather than a mock server.
• grpcmd is a free option for Windows, macOS, and Linux.
• ProtoCall is a freemium option for web, Windows, macOS, and Linux.

Verdict

GripMock is a strong choice for developers who need a free, configurable gRPC mock server for local work and automated tests, particularly when streaming and request-dependent behavior matter. Choose it for the control and breadth of its mock scenarios; look elsewhere if you need a hosted service or a client-first tool.