ASPERN

ASPERN Market API

The market around a position, crowding, correlation, who leads and who follows.

GitHub OpenAPI

Operations 5

GET /v1/crowding Who is in the same trade, and what share of the venue that is #
GET /v1/crowding/history Whether a crowd is building or dispersing #
GET /v1/funding What holding a perpetual costs or pays, and who is on each side #
GET /v1/markets Whether an instrument is still a market, and how much notional is marked in… #
GET /v1/lead-follow Pairs whose trades follow one another sooner than chance accounts for #

Specifications

⚙
OpenAPI
https://artifacts.apis.io/aspern-org/openapi/aspern-org-market-api-openapi.yml

Schemas & Data

📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-counterparty-check-schema.json
📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-trading-data-schema.json
📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-service-data-schema.json
📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-revenue-data-schema.json
📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-rwa-data-schema.json
📊
JSONSchema
https://artifacts.apis.io/aspern-org/json-schema/aspern-org-agent-profile-schema.json

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/aspern-org:aspern-org-market-api"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

aspern-org-market-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: ASPERN Market API
  version: '0.2'
  summary: The independent record of what machine-managed capital actually does.
  x-performance:
    simpleReads:
      p95Ms: 500
      meaning: A list or a lookup, warm.
    heavyAnalytics:
      p95Ms: 2000
      meaning: Correlation, the index, stress and cascade, warm.
    coldPath:
      meaning: 'The first call after a cache expires. Not covered by the figures above. The deploy and a five-minute timer warm the heavy free endpoints, so a caller should rarely meet one there. `/v1/correlation` is the exception and is the slowest: it needs a capability, so the warmer cannot reach past the gate without holding a key, and putting a credential in the web process to solve a latency problem is a trade we have not made. Expect several seconds on the first call after an expiry.'
    timeoutSeconds: 60
    maxWindowDays: 400
  description: 'Ratings are free. The data, the analytics and the certification are not.


    Every response states what it cannot see. Coverage, sample size and the mechanism behind a figure travel with the figure rather than sitting in documentation, because a number read without them is the failure this platform exists to prevent.'
  x-aspern-environment: production
  x-aspern-build: 20261101T2237Z-27da4c8c29
  x-contract-hash: 6c89cbaf2e2c50bd2b65bddf516e17b855704d01e471a6c06c19354fedc7367d
  x-stability:
    policy: additive-within-major
    promise: 'Within /v1 the contract only grows: new routes, optional parameters, fields and warning codes. Routes and fields are never removed or renamed, and no type, unit or status meaning changes.'
    deprecation:
      marker: 'x-lifecycle: deprecated, with the replacement named'
      minimumDays: 180
      removal: only in a new major version; /v1 keeps answering through the deprecation period
    verification: checked daily against the approved operation inventory; every change of x-contract-hash is recorded
    changelog: https://aspern.org/data/reference#changelog
servers:
- url: https://aspern.org/api
security:
- apiKey: []
tags:


# --- truncated at 32 KB (61 KB total) ---
# Full source: https://artifacts.apis.io/aspern-org/openapi/aspern-org-market-api-openapi.yml