Service Mesh Interface (SMI)
Service Mesh Interface (SMI) was a CNCF Sandbox specification that defined a standard, vendor-neutral set of Kubernetes Custom Resource Definitions (CRDs) for the most common service mesh capabilities: traffic policy, traffic telemetry, and traffic management. SMI's stated mission was "a standard interface for service meshes on Kubernetes," letting operators write portable traffic policy that worked across Linkerd, Open Service Mesh, Consul Connect, Istio (via adapter), Traefik Mesh, Gloo Mesh, and others without lock-in. The specification reached v0.6.0 (January 2021 / republished January 2024) and defined four resource groups across distinct API versions: Traffic Access Control (v1alpha3), Traffic Specs (v1alpha4), Traffic Split (v1alpha4), and Traffic Metrics (v1alpha1). Active development ceased in July 2022 when the maintainers shifted focus to the Kubernetes SIG-Network GAMMA initiative inside the Gateway API project. CNCF formally archived SMI on October 3, 2023, with the GitHub org and all repositories marked read-only on October 20, 2023. The CNCF announcement stated: "the maintainers have decided to consolidate efforts on a service mesh under the auspices of GAMMA under the Kubernetes SIG Network initiative." Gateway API GAMMA reached GA in the Standard Channel with Gateway API v1.1.0 and is now the de facto Kubernetes standard for service mesh configuration, superseding SMI. This profile documents SMI as a historical/archived standard. It is preserved so consumers of the API Evangelist network can (a) recognize legacy SMI manifests still deployed in the wild, (b) understand the conceptual lineage that fed into Gateway API GAMMA, and (c) migrate off SMI to Gateway API.
More than an index entry, but the surface is still mostly links rather than artifacts — the cohort most likely to move a full band from modest, well-targeted work.
API Evangelist profiles Service Mesh Interface (SMI) the way a machine reads it — 15 machine-readable artifacts across 4 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Service Mesh Interface (SMI) scores 29.7/100 (emerging), with a separate agent-readiness read of 7/100 (human only). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Service Mesh Interface (SMI)
Each block below is one kind of artifact we hold for Service Mesh Interface (SMI). For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 4
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
SMI Traffic Access Control
Traffic Access Control defines the `TrafficTarget` resource, which associates a set of traffic rules with a service identity allocated to a group of pods. It is the authorizatio...
SMI Traffic Specs
Traffic Specs describes a set of resources that allow users to specify how their traffic looks. It is used in concert with access control and other policies to concretely define...
SMI Traffic Split
Traffic Split defines the `TrafficSplit` resource, which allows users to incrementally direct percentages of traffic between various services. It is the canonical SMI primitive ...
SMI Traffic Metrics
Traffic Metrics is "a resource that provides a common integration point for tools that can benefit by consuming metrics related to HTTP traffic." It is exposed as a Kubernetes A...
Semantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Spectral Rules 1
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
JSON Schema 6
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
SMI HTTPRouteGroup
JSON SCHEMASMI TCPRoute
JSON SCHEMASMI TrafficMetrics
JSON SCHEMASMI TrafficSplit
JSON SCHEMASMI TrafficTarget
JSON SCHEMASMI UDPRoute
JSON SCHEMAJSON Structure 1
JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.
JSON Structure definitions describing this provider's data shapes.
Service Mesh Interface Structure
JSON STRUCTUREExamples 1
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Traffic Metrics Example
EXAMPLESecurity Posture 1
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Resources
Every other property we hold for Service Mesh Interface (SMI) — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Documentation 6
Reference material describing how the API behaves
Design & Contract 2
Pagination, idempotency, versioning, errors, and events
Build 5
SDKs, sample code, and the tooling you integrate with
Access & Security 1
Authentication, authorization, and security posture
Operate 1
Status, limits, changes, and where to get help
Commercial 1
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
Other 10
Properties that don't map to a standard resource type
Scroll within the panel for all 10 ·
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