Kratos is live · free · last verified 26 Oct 2026 · viability monitor
Kratos
Kratos is an open-source Go framework for building Protobuf-first microservices over HTTP and gRPC, with Blades for LLM agents.
Kratos earns its place when your team already lives in Go and Protobuf: one contract, both HTTP and gRPC, and middleware you can compose instead of reinvent. The v3 core is deliberately small, which is a strength until you need batteries — registry, persistence and deployment are yours to choose and run. Blades is the interesting wildcard; it gives Go shops a native path to LLM agents, though the ecosystem is younger than the microservice side.
Verdict generatedVerified 4d ago · liveness 63/100 · cite: rightaichoice.com/tools/kratos
- Go developers building cloud-native microservices over HTTP and gRPC
- Platform engineers standardizing one service skeleton across teams
- Teams that define APIs first in Protobuf and generate bindings
- Go teams adding LLM agents or workflows without a separate Python service
- Beginners unfamiliar with Go, gRPC or microservices layering
- Teams that want hosting, scaling and CI/CD handled for them
- Projects that need a full-stack framework with frontend support
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Skip Kratos if you want a managed platform that handles hosting, scaling and deployment policy for you, or if your stack has no Go, Protobuf or gRPC experience to build on.
Kratos's pricing fits teams whose volume aligns with the published tiers. Compare against the alternatives listed below for stage-specific value.
In short
Kratos — Kratos is an open-source Go framework for building Protobuf-first microservices over HTTP and gRPC, with Blades for LLM agents. Best for Go developers building cloud-native microservices over HTTP and gRPC, Platform engineers standardizing one service skeleton across teams, Teams that define APIs first in Protobuf and generate bindings. Free to use.
What is Kratos?
Kratos — Kratos is an open-source Go framework for building Protobuf-first microservices over HTTP and gRPC, with Blades for LLM agents. Best for Go developers building cloud-native microservices over HTTP and gRPC, Platform engineers standardizing one service skeleton across teams, Teams that define APIs first in Protobuf and generate bindings. Free to use.
Kratos is the Go framework for microservices that keeps complex systems legible. You write your API once in Protobuf, and Kratos gives HTTP and gRPC a single, consistent service contract — the same Greeter service can live on an HTTP server and a gRPC server inside one application. Around that core sit composable middleware for logging, authentication, rate limiting and tracing, so cross-cutting concerns stay out of your business logic. The framework also exposes interfaces for configuration sources, service discovery, codecs and structured errors, plus logging, metrics and distributed tracing hooks for observing the whole system. The project ships a working template (kratos-layout) with clear boundaries between API, business logic and data, and a CLI that scaffolds services, generates Protobuf code and lints definitions. Persistence, registry, telemetry exporters and deployment policy are left to you — Kratos does not silently configure them. The homepage frames it as "the foundation for services, the space to create," and the code backs that up: a thin application that owns server lifecycles and a middleware type shared across transports. Beyond microservices, Kratos bundles Blades, a modular architecture for building AI agents and workflows in Go. A recent blog post separates Workflow (fixed, predefined steps) from Agent (LLM-driven autonomy) and walks through constructing both on Blades, which means Go teams can add LLM features without standing up a separate Python service. It's MIT-licensed and self-hosted, so you own the deployment and CI/CD story. That fits Go developers and platform engineers who already think in Protobuf, gRPC and service layering. If you want a managed PaaS or a full-stack framework with frontend support, Kratos will feel like more wiring than you signed up for.
Key features
- Protobuf-defined APIs generating both HTTP and gRPC bindings
- Concurrent server lifecycle with hooks, signals, registration and graceful shutdown
- Composable middleware for logging, authentication, rate limiting, tracing and recovery
- Built-in logging, metrics and distributed tracing interfaces
- Structured errors generated from Protobuf definitions
- Configuration interfaces with pluggable multiple data sources
- Service discovery and registry interfaces with selectors and node filters
- Codec registry for content encoding selection
- Project CLI for scaffolding, Protobuf generation and linting
- kratos-layout template with clear API, business logic and data boundaries
- Blades modular architecture for AI agents and workflows in Go
- Workflow support for fixed, predefined steps alongside LLM-driven agents
- HTTP streaming and unary/streaming RPCs
Behind the verdict
Pick Kratos if you are building Go microservices and want the API contract to drive everything. Protobuf-first means HTTP and gRPC stay in sync, and the middleware model keeps logging, auth, rate limiting and tracing out of your handlers. Platform teams standardizing a service skeleton across many repos will appreciate the layout template and CLI more than they expect. Pass if you need a managed platform. Kratos is MIT-licensed and self-hosted; you supply registries, persistence, telemetry exporters and CI/CD. The docs are explicit that the reference layout's choices (Wire, Ent, MySQL) are optional, which is freeing but also means the framework won't make those decisions for you. The closest comparison is go-micro or a heavier framework like Go kit. Kratos bets on Protocol Buffers as the source of truth and keeps the runtime thin; if your team prefers hand-rolled HTTP with a router, the Protobuf toolchain will feel like ceremony. In practice, the payoff shows up when you add a second transport or a new service and the generated bindings just work. Blades is where I'd watch closely. The recent blog distinction between fixed Workflow steps and LLM-driven Agent autonomy is the right mental model, and running agents in Go avoids a Python sidecar. But it's early — treat Blades as a promising addition to a microservices framework, not a reason alone to adopt Kratos. One caveat: the framework's discipline is real. You'll write Protobuf, run code generation and understand the layering before the first endpoint responds. Teams that want instant gratification should look elsewhere.
Models under the hood
as of 2026-10-24
Limitations
- Kratos is self-hosted — the framework ships no managed hosting, so you provide deployment, CI/CD and infrastructure.
- The docs are explicit that it does not silently configure database access, queues, caches, migrations, telemetry exporters or deployment policy; those are application choices you wire yourself.
- In v3, JWT and OpenTelemetry tracing/metrics live as contrib modules rather than core, so check the module path before copying an example.
- It is a microservices framework, not a full-stack web framework, and it provides no frontend support.
- The reference layout uses Wire, Ent, MySQL and SQLite, but the docs note Kratos does not require any of them — useful flexibility that also means sample code can look more opinionated than the framework is.
- The learning curve assumes working Go, Protobuf and gRPC knowledge.
as of 2026-10-09
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Is Kratos still active?
Kratos is live · free · last verified 26 Oct 2026 · viability monitor.
Viability score
How well maintained and how widely used is Kratos? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: October 2026
How we score →What do users say about Kratos?
What people actually say about Kratos — is it worth it?
Our community sentiment research written Jul 18, 2026 is more than 90 days old, so it is being re-reviewed against current data and is not shown.
How we verified this
Every listed fact about Kratos— pricing, features, links, status — is re-read from the vendor's own pages by our verification pipeline and each change is logged with a date; the last pass ran on 26 Oct 2026. Pages mix model-assisted synthesis with human review; see how we verify.
Verification history
We have re-verified Kratos 10 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — changed who it suits, features, our verdict, summary, who should skip it, description, integrations
- — changed description, pricing fit, setup time, our verdict, use cases, features, who it suits, summary, integrations, limitations, switching in, switching out, models, who should skip it
- — changed SSL certificate
- — changed pricing page
- — changed integrations, models, limitations, who should skip it, switching in, description, who it suits, pricing fit, use cases, features, switching out, summary, hidden costs, our verdict, setup time
- — changed domain expiry
Showing the 6 most recent of 10 verification passes.
Free to cite with attribution — this page re-verifies continuously.
How much does Kratos cost in 2026?
Kratos: Free to use. Pricing last verified 26 Oct 2026.
Where the pricing makes sense
The company stage and team size where Kratos's pricing actually pencils out — and where peers do it cheaper.
Kratos's pricing fits teams whose volume aligns with the published tiers. Compare against the alternatives listed below for stage-specific value.
Has Kratos' pricing changed?
No plan price for Kratos has moved since we began logging in Aug 2026; the pricing page is re-read on every verification pass.
Who should pick Kratos?
Pick Kratos if you are Go developers building cloud-native microservices over HTTP and gRPC, Platform engineers standardizing one service skeleton across teams, Teams that define APIs first in Protobuf and generate bindings, Go teams adding LLM agents or workflows without a separate Python service.
Look elsewhere if you are Beginners unfamiliar with Go, gRPC or microservices layering, Teams that want hosting, scaling and CI/CD handled for them, Projects that need a full-stack framework with frontend support, Teams unwilling to adopt Protobuf and code generation.
Skip it if Skip Kratos if you want a managed platform that handles hosting, scaling and deployment policy for you, or if your stack has no Go, Protobuf or gRPC experience to build on.
GeneratedReal-world workflow fit
Concrete scenarios for the personas Kratos actually fits — and what changes day-one when you adopt it.
Copy the maintained reference layout, run the Kratos CLI to regenerate the Protobuf bindings, and stand up the documented Todo service with its HTTP and gRPC servers registered on one kratos.New() app.
Outcome: A running service with generated bindings on both transports, a service/biz/data layout the rest of the team can copy, and repository tests you can extend.
Wire Blades into the same repo as the service: blades.NewAgent with the OpenAI chat provider and a gpt-5 model, an instruction string, and a runner executing a blades.UserMessage.
Outcome: An agent loop that lives in Go alongside the service, with no separate Python sidecar to deploy or monitor.
Apply the middleware type across generated handlers for recovery, logging, metadata, validation, rate limiting and circuit breaking, then add tracing and metrics through the contrib modules.
Outcome: One consistent request pipeline across HTTP and gRPC endpoints, with observability you can point at your own exporters.
Use cases
- Build a production-ready Go microservice with one Protobuf contract exposed over both HTTP and gRPC.
- Add tracing and metrics through contrib modules to an existing Go service.
- Apply rate-limiting, authentication and validation middleware uniformly across HTTP and gRPC handlers without rewriting transport code.
- Build an LLM-powered agent in Go with Blades using the OpenAI chat provider and a gpt-5 model.
- Model a multi-step task as a deterministic workflow instead of depending on per-step LLM decisions.
- Keep configuration in a source you control and read it as typed structures with a codec registry.
- Scaffold a new service, generate mocks and start from the maintained reference layout with the Kratos CLI.
Setup time & first value
How long it actually takes to get something useful out of Kratos — broken out by persona, not the marketing-page minute.
Setup time varies by use case. Solo users typically reach first value within an hour; teams should budget half a day for shared setup including integrations and access controls.
Switching to or from Kratos
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
- →From a hand-rolled net/http and gRPC setup: define your service contract once in Protobuf and let Kratos generate both the HTTP and gRPC bindings, then move cross-cutting logic into shared middleware.
- →From Kratos v2: follow the Migrate from v2 to v3 guide first, then review New Features in Kratos v3 before moving services over.
- →From a Python LLM service: rebuild the agent loop with Blades and the OpenAI chat provider so the feature runs in the same Go process as your service.
- ↗To a full-stack framework with frontend support: there is no shared component model to carry over — your Protobuf contracts and generated bindings are the parts worth keeping.
- ↗To a managed platform: export the service definitions and middleware behavior, then reimplement the lifecycle wiring the managed runtime provides.
Integrations
Tutorials & Learning
YouTube returned 6 videos for “Kratos”, and we withheld 6: 6 could not be judged, because “Kratos” is a single word that other videos use for other things. We are showing none, because we could not prove any of them are about Kratos.
Official links
What are the best Kratos alternatives?
The closest alternatives to Kratos we list are OpenSpec, Plate and Taste Skill. Ranked by direct product-type match, not category overlap.
| Alternative | Pricing | Starts at | Last verified |
|---|---|---|---|
| OpenSpec | Free | Free | — |
| Plate | Free | Free | — |
| Taste Skill | Free | Free | — |
Alternatives to Kratos
View all
OpenSpec
OpenSpec is an open-source spec-driven development framework that keeps AI coding agents building the right thing, with verify and archive
Plate
Open-source React framework for building a custom rich-text editor, with headless plugins, copy-in UI components and an MCP-ready AI plugin
Taste Skill
Open-source SKILL.md rules that stop AI coding agents shipping generic frontend UI
Tools that pair well with Kratos
Common stack mates teams adopt alongside Kratos, with the specific reason each pairing earns its keep.
OpenSpec
OpenSpec is an open-source spec-driven development framework that keeps AI coding agents building the right thing, with verify and archive
Plate
Open-source React framework for building a custom rich-text editor, with headless plugins, copy-in UI components and an MCP-ready AI plugin
Taste Skill
Open-source SKILL.md rules that stop AI coding agents shipping generic frontend UI
Kratos vs its closest rival
Kratos's closest head-to-head is with Spider Cloud — These tools serve entirely different needs. Spider Cloud is a web data extraction API for AI agents and RAG, while Kratos is a Go framework for building microservices with optional AI agent capabilities. Choose Spider Cloud if you need to fetch structured web data at scale; pick Kratos if you're developing cloud-native services in Go. They are not direct competitors. Verdict generated
Head-to-head comparisons
Kratos vs Spider Cloud
These tools serve entirely different needs. Spider Cloud is a web data extraction API for AI agents and RAG, while Kratos is a Go framework for building microservices with optional AI agent capabilities. Choose Spider Cloud if you need to fetch structured web data at scale; pick Kratos if you're developing cloud-native services in Go. They are not direct competitors.
GeneratedKratos vs Voyage Ai
These tools solve completely different problems: Voyage AI is a paid API for high-accuracy RAG embeddings (ideal for enterprise search), while Kratos is a free open-source Go framework for building microservices with optional AI agents. Choose Voyage if you need top-tier retrieval on domain-specific data; choose Kratos if you're a Go developer building cloud-native services and want to add LLM agents via the Blades architecture.
GeneratedKratos vs Temporal Ai
Choose Temporal AI if you need a battle-tested, multi-language durable execution platform for reliable AI agents and workflows—especially if you require human-in-the-loop, automatic retries, and a managed cloud option. Choose Kratos if you're a Go-only team building cloud-native microservices with Protobuf and want to add LLM agent capabilities via the Blades framework, and you prefer a lightweight, open-source framework over a platform.
GeneratedFrequently asked questions
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