Need help with your APIs? I offer API discovery, governance & evangelism services. Explore services →
API Evangelist API Evangelist
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC
Scalar website screenshot

Scalar

Scalar is an open-source API platform built around the OpenAPI standard. It provides API documentation (API References), an offline-first API client, a centralized API registry for managing OpenAPI documents, JSON schemas and Spectral rules, and automated SDK generation for TypeScript, Python, Go, PHP, Java, and Ruby. Used by teams at SmartBear, Microsoft ASP.NET, and 30+ framework ecosystems including Express, FastAPI, NestJS, and Spring Boot. The platform has 14.9k GitHub stars and is MIT licensed. Scalar is backed by a strong open-source community and positions itself as the modern, open alternative to Swagger UI and Postman.

agent ready

Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.

Kin Score

API Evangelist profiles Scalar the way a machine reads it — 47 machine-readable artifacts across 30 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 — Scalar scores 56.7/100 (developing), with a separate agent-readiness read of 55/100 (agent ready). 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 Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 56.7/100 · developing
Contract Quality 13.9 / 25
Developer Ergonomics 5.2 / 20
Commercial Clarity 11.6 / 20
Operational Transparency 6.8 / 13
Governance 10.4 / 12
Discoverability 8.8 / 10
Agent readiness — 55/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 15 / 15
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3

How we profile Scalar

Each block below is one kind of artifact we hold for Scalar. 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 30

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.

Scalar API References

Scalar API References renders modern, interactive API documentation from OpenAPI and Swagger specifications. Features include multiple themes, custom styling, dark mode, mobile ...

Scalar API Client

Scalar API Client is a fully open-source, offline-first REST API client built on the OpenAPI standard. Supports collections, environments, pre/post-response scripting, test resu...

Scalar Docs

Scalar Docs enables teams to create and publish developer documentation that stays in sync with their API and code. Supports writing with a WYSIWYG editor, pulling Markdown and ...

Scalar Registry

Scalar Registry provides centralized management and versioning of OpenAPI Documents, JSON Schemas, and Spectral Rules with deep Git integration. Serves as the single source of t...

Scalar SDKs

Scalar SDKs generates type-safe client libraries from OpenAPI specifications. Supported languages include TypeScript, Python, Golang, PHP, Java, and Ruby. Features include autom...

Scalar CLI

The Scalar CLI is a command-line interface for managing OpenAPI files, generating documentation, running mock servers, validating specs, and publishing to the Scalar Registry. E...

Scalar access-groups API

The access-groups API from Scalar — 5 operation(s) for access-groups.

Scalar analytics API

The analytics API from Scalar — 4 operation(s) for analytics.

Scalar api-docs API

The api-docs API from Scalar — 13 operation(s) for api-docs.

Scalar auth API

The auth API from Scalar — 27 operation(s) for auth.

Scalar docs API

The docs API from Scalar — 6 operation(s) for docs.

Scalar Docs Projects API

The Docs Projects API from Scalar — 9 operation(s) for docs projects.

Scalar Forgejo API

The Forgejo API from Scalar — 1 operation(s) for forgejo.

Scalar github API

The github API from Scalar — 16 operation(s) for github.

Scalar Internal API

The Internal API from Scalar — 1 operation(s) for internal.

Scalar login-portals API

The login-portals API from Scalar — 3 operation(s) for login-portals.

Scalar payment API

The payment API from Scalar — 6 operation(s) for payment.

Scalar publish API

The publish API from Scalar — 11 operation(s) for publish.

Scalar pubsub API

The pubsub API from Scalar — 7 operation(s) for pubsub.

Scalar rules API

The rules API from Scalar — 6 operation(s) for rules.

Scalar schemas API

The schemas API from Scalar — 7 operation(s) for schemas.

Scalar sdks API

The sdks API from Scalar — 18 operation(s) for sdks.

Scalar share API

The share API from Scalar — 1 operation(s) for share.

Scalar signup API

The signup API from Scalar — 1 operation(s) for signup.

Scalar team API

The team API from Scalar — 36 operation(s) for team.

Scalar themes API

The themes API from Scalar — 4 operation(s) for themes.

Scalar utility API

The utility API from Scalar — 3 operation(s) for utility.

Scalar vcs API

The vcs API from Scalar — 6 operation(s) for vcs.

Scalar waitlist API

The waitlist API from Scalar — 1 operation(s) for waitlist.

Scalar workspace API

The workspace API from Scalar — 6 operation(s) for workspace.

Scroll within the panel for all 30 ·

Open Collections 1

Open, tool-agnostic collections carry the same runnable value as Postman without locking you to one client — the portable, forkable form of the same exercise.

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

Core

OPEN COLLECTION

Pricing Plans 1

Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the six things the Kin Score reads for commercial clarity.

Published pricing tiers and plan structures.

Scalar Plans Pricing

3 plans

PLANS

Rate Limits 1

Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.

Documented rate limits and quota policies.

Scalar Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.

Cost, billing, and metering signals for API financial operations.

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.

Scalar Context

34 classes · 1 properties

JSON-LD

Spectral Rules 2

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.

Scalar API Rules

5 rules · 3 warnings

SPECTRAL

Scalar API Rules

16 rules · 4 errors · 12 warnings

SPECTRAL

JSON Schema 1

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.

Scalar OpenAPI Document Reference

12 properties

JSON SCHEMA

JSON 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.

Scalar Openapi Document Structure

0 properties

JSON STRUCTURE

Examples 3

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.

Security Posture 4

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.

Scalar Authentication

http · 1 scheme

SECURITY

Scalar Domain Security

TLSv1.3 · DMARC

SECURITY

Scalar Vulnerability Disclosure

disclosure policy published

SECURITY

Scalar Trust Center

SOC 2, GDPR

SECURITY

Agentic Access 1

An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.

Recommended x-agentic-access execution contracts for AI agents.

Scalar Agentic Access

224 operations · 175 acting · 3 human-in-the-loop

224 operations · 175 acting

AGENTIC

Resources

Every other property we hold for Scalar — 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 2

Reference material describing how the API behaves

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

Build 2

SDKs, sample code, and the tooling you integrate with

Operate 3

Status, limits, changes, and where to get help

Commercial 1

Pricing, plans, and the legal terms of use

Company 3

The organization behind the API

Other 1

Properties that don't map to a standard resource type

← All providers · Data indexed from github.com/api-evangelist/scalar · machine-readable index on apis.io