GripMock

Overview

GripMock is a self-hosted mock server for teams building or testing gRPC services, especially when a live backend is unavailable or undesirable. Its strongest case is controlled testing: it can model request-dependent replies, streaming calls, and failure conditions without requiring a backend.

Deployment choices span standalone installations and a Go SDK embedded in the test process, though users should expect to run and manage the server themselves.

Key features

Matching and response control

Stubs can match request inputs and headers with exact, partial, regex, glob, and any-of rules, and priorities help decide between overlapping matches. This range supports tests that need to distinguish realistic request variants rather than return one fixed response. Dynamic templates can use payloads, headers, and stream position, while configurable status errors and delays let teams cover client error handling and timeout behavior.

Streaming and live editing

Support for unary, server-streaming, client-streaming, and bidirectional calls makes GripMock relevant beyond simple request-response tests. Its dashboard at http://localhost:4771/ shows loaded and matched stubs, including which remain unused, and permits creating, editing, and deleting stubs while the server runs. That is useful when adjusting a scenario during development, but it does not remove the need to own the server setup.

Service definitions and integrations

GripMock accepts .proto files and compiled .pb descriptors, including descriptors pushed from 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 cover varied workflows, and an official GitHub Actions guide helps fit it into CI. A Go SDK can run GripMock inside the test process without a separate container or binary, a practical option for Go test suites that want fewer external moving parts.

Native gRPC TLS and optional mutual TLS client-certificate authentication address encrypted and certificate-authenticated setups. OTLP trace export and a Prometheus-scrapable /metrics endpoint provide observability hooks. MCP endpoints extend it to AI-agent and tool-driven automation, while gRPC-Web support and server reflection broaden its protocol-related capabilities.

Pricing

GripMock is free and open source under the MIT License, with no paid tiers or seat and quota distinctions described. That makes it straightforward to use across local development and CI without a software license cost; the trade-off is self-hosting and handling the server as part of your test environment. Bug reports and questions go through GitHub issues.

Platforms

GripMock is listed for Linux, macOS, and Windows, as well as web, API, and self-hosted use. The dashboard is accessed through the running server, while installation options include Docker, binaries, Homebrew, shell script, and Go.

Who it's for

GripMock suits gRPC developers and test engineers who need repeatable backend-independent scenarios, particularly teams covering streaming behavior, matching edge cases, failures, or timeouts. CI users can follow the Docker workflow, while Go teams can embed it in tests. It is a weaker fit for someone seeking a hosted mock service or a graphical gRPC client rather than a server they operate.

Pros and cons

• Pros: Flexible matching, dynamic replies, and error or delay controls support more varied tests than fixed-response stubs.
• Pros: All four gRPC call patterns are supported, with live dashboard editing and visibility into unused stubs.
• Pros: Multiple install paths, a Go SDK, GitHub Actions guidance, and schema-registry support fit different development and CI setups.
• Cons: The self-hosted deployment model means users must arrange and maintain the server environment.
• Cons: Questions and bug reports are directed to GitHub issues, rather than a stated dedicated support channel.

Alternatives

For a gRPC client interface rather than a mock server, consider grpcui, a free, MIT-licensed option for Linux, macOS, Windows, web, and self-hosted use. Kreya is another client-oriented alternative, with a free individual plan that limits request history to the latest request; it is freemium and not open source.

BloomRPC Extended is a free desktop alternative for Linux, macOS, and Windows. FintX offers a free open-source plan with unlimited gRPC clients, request autosave, import/export, per-method tabs, a JSON editor, and projects on Linux, macOS, and Windows.

Bandura provides a free plan for personal and commercial use without accounts, paid seats, or feature tiers, and lists a separate commercial licence. Evans is a free open-source gRPC client for Linux, macOS, and Windows; grpcmd is a free option for those same desktop platforms. ProtoCall is a freemium alternative for web, Windows, macOS, and Linux.

Browse more options in gRPC Tools.

Verdict

Choose GripMock if your priority is a self-hosted gRPC mock server with nuanced matching, streaming coverage, and practical failure controls. Its free MIT licensing and in-process Go SDK make it particularly compelling for development and automated tests. Look elsewhere if you need a hosted service or a gRPC client rather than a server to integrate into your environment.