Alpaca
Alpaca is a developer-first, commission-free brokerage that exposes stock, ETF, options, and crypto trading and market data entirely through APIs. The Trading API places and manages orders against a free paper-trading sandbox (paper-api.alpaca.markets) or a live account (api.alpaca.markets/v2); the Market Data API serves historical and real-time stocks, crypto, options, news, and corporate actions over REST plus WebSocket streams (data.alpaca.markets and stream.data.alpaca.markets); and the Broker API lets businesses open and fund end-user brokerage accounts. Authentication uses APCA-API-KEY-ID and APCA-API-SECRET-KEY headers, with OAuth2 available for third-party apps.
Limited machine-readable signal and partial portal coverage — documentation a human can read, but little a machine or agent can consume without scraping.
API Evangelist profiles Alpaca the way a machine reads it — 23 machine-readable artifacts across 16 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 — Alpaca scores 40.4/100 (thin), with a separate agent-readiness read of 44/100 (agent aware). 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 Alpaca
Each block below is one kind of artifact we hold for Alpaca. 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 16
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.
Alpaca Market Data Streaming API
Real-time market data over WebSocket. Stocks stream at wss://stream.data.alpaca.markets/v2/{feed} (iex, sip, delayed_sip, test) and crypto at wss://stream.data.alpaca.markets/v1...
Alpaca Account API
Trading account details, configuration, and activities.
Alpaca Assets API
Tradable asset catalog.
Alpaca Broker - Accounts API
Open and manage end-user brokerage accounts.
Alpaca Broker - Funding API
Transfers and journals between accounts.
Alpaca Broker - Trading API
Place orders on behalf of end-user accounts.
Alpaca Market API
Market calendar and clock.
Alpaca Market Data - Crypto API
Historical and latest crypto bars, trades, quotes, and orderbooks (v1beta3).
Alpaca Market Data - News API
Real-time and historical market news (v1beta1).
Alpaca Market Data - Options API
Options bars, trades, and snapshots (v1beta1).
Alpaca Market Data - Screener API
Most-actives and movers screeners (v1beta1).
Alpaca Market Data - Stocks API
Historical and latest stock bars, trades, quotes, snapshots, and auctions.
Alpaca Orders API
Submit, list, replace, and cancel orders.
Alpaca Portfolio API
Portfolio history and performance.
Alpaca Positions API
Open positions and liquidation.
Alpaca Watchlists API
User watchlists.
Scroll within the panel for all 16 ·
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).
Alpaca API
OPEN COLLECTIONPricing 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.
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.
Alpaca Markets 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.
Alpaca Markets Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Alpaca Market Data Streaming (WebSocket)
AsyncAPI 2.6 description of Alpaca's **real-time market data WebSocket API**. Unlike many providers, Alpaca publishes a genuine, documented public WebSocket (`wss://`) surface f...
ASYNCAPISpectral 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.
Alpaca API Rules
SPECTRALAgentic 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.
Resources
Every other property we hold for Alpaca — 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 1
Reference material describing how the API behaves
Agent Surfaces 1
MCP servers, agent skills, and machine-readable catalogs
Build 1
SDKs, sample code, and the tooling you integrate with
Operate 1
Status, limits, changes, and where to get help
Commercial 2
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
← All providers · Data indexed from github.com/api-evangelist/alpaca-markets · machine-readable index on apis.io