API Stack
API Stack is a free, public directory and discovery platform for third-party API tooling, built and operated by Apideck B.V. as a tenant of its own Apideck Ecosystem marketplace platform. It catalogs 213 API tools and services across 46 published category pages spanning the whole API lifecycle: gateways, management, design, authentication, developer portals, documentation, specifications, testing, mocking, security, monitoring, analytics, billing, frameworks, linters and directories, with per-tool listing pages carrying descriptions, screenshots and outbound links so developers can shortlist and compare tooling. API Stack is a discovery surface rather than an API product: it publishes no developer portal, API reference, machine-readable contract, SDK, pricing page or terms of service of its own, and sits alongside Apideck's API Tracker, Open Banking Tracker and SaaS Blocks properties.
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 API Stack the way a machine reads it — 15 machine-readable artifacts across 1 API, 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 — API Stack scores 14.1/100 (emerging), with a separate agent-readiness read of 3/100 (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.
Why this profile is thin
apistack.io is a 213-listing directory website with no developer surface of its own — /docs, /api-docs and /pricing all return 404, the 268-URL sitemap contains no developer, reference or pricing page, and no /.well-known/ document is served; the one machine-readable endpoint on the host, /api/graphql, is the Apideck Ecosystem platform backend that apistack.io runs on as a tenant (its schema is Marketplace/Listing/Partner plus Unify/Vault/Connection types), is disallowed in robots.txt, and is therefore catalogued under Apideck rather than credited to API Stack.
This is an honest zero, not a gap in our research. API Stack does not appear to expose an API, so there is nothing here for us to index and nothing for them to fix.
What we probed
https://www.apistack.io/docs→ HTTP 404https://www.apistack.io/api-docs→ HTTP 404https://www.apistack.io/pricing→ HTTP 404https://www.apistack.io/.well-known/api-catalog→ HTTP 404https://www.apistack.io/sitemap.xml→ HTTP 200https://www.apistack.io/api/graphql→ HTTP 200
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. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-10-03 · rubric v0.23.0
Put this on your own site. The badge is drawn live from API Stack's current Kin Score — paste it once and it updates itself every time the score is recomputed. It follows your visitor's light or dark setting, and it links back here so anyone who sees it can read the full breakdown.
<!-- Kin Score · API Evangelist -->
<a href="https://providers.apievangelist.com/providers/api-stack/"
title="API Stack on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/api-stack.svg"
alt="API Stack Kin Score — API readiness rating by API Evangelist" width="150" height="150" loading="lazy">
</a>[](https://providers.apievangelist.com/providers/api-stack/)<!-- Kin Score · API Evangelist -->
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title="API Stack on API Evangelist — API profile and Kin Score">
<img src="https://apis.io/badge/api-stack/card.svg"
alt="API Stack Kin Score — API readiness rating by API Evangelist" width="340" height="120" loading="lazy">
</a>More shapes, themes and sizes → · Score as JSON · How badges work
How we profile API Stack
Each block below is one kind of artifact we hold for API Stack. 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 1
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.
API Stack Directory
The API Stack Directory is a searchable catalog of 213+ API tools and services organized into 50+ categories. Each listing includes descriptions, features, pricing, screenshots,...
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 things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
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.
Api Stack Rate Limits
RATE LIMITSFinOps 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.
Api Stack Finops
FINOPSFeatures 5
The notable capabilities this provider advertises, captured as structured features so they can be searched and compared instead of read one landing page at a time.
Notable capabilities this provider offers.
213+ Tools Catalog
Comprehensive listing of API tools and services across 50+ categories with descriptions, features, and pricing.
Category Browsing
Organized categories for browsing by API lifecycle stage including design, development, testing, security, and monitoring.
Search and Discovery
Full-text search to find specific API tools matching developer requirements.
Tool Comparison
Detailed listing pages with features, pricing, and screenshots to help compare similar tools.
Powered by Apideck
Built and maintained by Apideck as part of the broader API ecosystem alongside API Tracker and Open Banking Tracker.
Security 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.
Use Cases 5
What developers actually build with this provider — captured so the catalogue answers 'what is this for', not just 'what does this expose'.
What developers build with this provider.
API Tooling Discovery
Developers and architects find and evaluate API tools across all stages of the API lifecycle.
API Gateway Selection
Compare API gateway options from open source to enterprise to find the right solution for infrastructure needs.
API Security Tool Research
Discover API security testing, authentication, and monitoring tools for securing API programs.
API Design Tool Evaluation
Explore API design tools, editors, and specification validators to improve API development workflows.
Developer Portal Platforms
Research developer portal platforms and documentation tools for publishing API programs.
Resources
Every other property we hold for API Stack — 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.
Get Started 2
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 2
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 1
Pagination, idempotency, versioning, errors, and events
Build 1
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Commercial 1
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
Other 5
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/api-stack · machine-readable index on apis.io
This is an independent, third-party profile of API Stack, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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you will get a person, not a form — we will tell you exactly which public URLs this profile was built from.