Helious

Helious provides a live US market news terminal delivering real‑time economic calendar events, Treasury auction results, and release forecasts. Users can view live squawk, score releases against consensus instantly, and track yield curves and Fed speaker commentary, all without a subscription card.

Helious publishes 12 API contracts indexed on the APIs.io network, including Agent sign-in and A2A API, Ask Helious API, Boards API, and 9 more. Tagged areas include Finance, Market Data, News, Economic Calendar, and Treasury.

The Helious catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

Helious’ developer surface includes API reference, authentication, engineering blog, documentation, getting-started guide, support, pricing, and 26 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

51.4/100 developing Agent 51/100 agent ready Full breakdown ↓
scored 2026-11-13 · rubric v0.28.0 · Show this score on your site →

AccessFreemiumSelf serve⚡ Free to try

1 published contract 1 MCP Servers

Finance Market Data News Economic Calendar Treasury

Kin Score

Kin Score How this is scored →
scored 2026-11-13 · rubric v0.28.0

Composite quality — 51.4/100 · developing

Contract Quality 13.2 / 21

Developer Ergonomics 10.8 / 17

Access Clarity 5.8 / 17

Operational Transparency 3.2 / 11

Contract Governance 2.2 / 10

Discoverability 6.5 / 9

Regulatory Posture 5.4 / 15

Agent readiness — 51/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 8 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 0 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Securities & Market Data regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented) Ask about this →
Rate-Limit Signaling +7 pts — OpenAPI responses document X-RateLimit-* / RateLimit headers (verified), else a rate_limits artifact or RateLimits link (documented) Ask about this →
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks Ask about this →
Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too Ask about this →
Pagination +5 pts — share of collection GETs (an array, or one wrapped in data/items/results ...) that declare a page/limit/offset/cursor parameter, a Link header or a next/cursor field; na with no collection GETs Ask about this →
Agentic Commerce Well-Known Document +5 pts — a parsing /.well-known/ucp.json or acp.json declaring a version and at least one service, OR (0.27) a live x402 payment challenge from _data/x402-adoption.json — `self` when its endpoints are on the provider's own domain, `platform` when they are on a vendor's Ask about this →

2 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 34.0 — up to +13.2 composite points Ask about this →
Contract Quality scores 62.0 — up to +9.5 composite points Ask about this →
Contract Governance scores 22.0 — up to +9.4 composite points Ask about this →

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Not sure how this applies to your stack? Ask about any one item. Kin Lane reads every question, looks at your profile and your situation, and replies with what a fix would take — scoped to that one area, priced up front, yours whether you ship it or not. Ask a question →

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/helious-io/apis.yml: open an issue on github.com/api-evangelist/helious-io to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 5

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

Agent2Agent

measured — observed by APIs.io (conformant)

Model Context Protocol (MCP)

measured — observed by APIs.io (documented)

OAuth 2.0 Protected Resource Metadata

measured — observed by APIs.io (verified)

Dynamic Client Registration

measured — observed by APIs.io (published)

OpenAPI

measured — observed by APIs.io (published)

APIs 12

Individual APIs this provider publishes, each with its own machine-readable definition.

Helious Agent sign-in and A2A API

OAuth 2.1 so an agent can act for a person without a pasted key, and the agent-to-agent endpoint for asking the desk a question in plain words.

Helious Ask Helious API

The Ask Helious API from Helious — 1 operation(s) for ask helious.

Helious Boards API

The FX momentum, implied volatility, correlation and Hormuz boards: newest reading plus history.

Helious Economic data API

Every tracked US economic series, the calendar, and release prints with their surprise scores.

Helious News and feed API

The Helious feed: the news wire and the desk's own posts, each with a score for bonds and one for stocks.

Helious Rates and curve API

Live Treasury yields, spreads, the curve regime and its history.

Helious Reference API

Glossary, the measured capture latency and supporting reference data.

Helious Series API

The Series API from Helious — 2 operation(s) for series.

Helious The Fed API

FOMC meetings, the roster and upcoming speakers.

Helious The squawk API

The The squawk API from Helious — 2 operation(s) for the squawk.

Helious Treasury auctions API

Auction results by tenor, with the tail against the when-issued yield.

Helious Your key API

What your key is and what it may do.

Scroll for all 12

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Helious MCP Server

Remote MCP server at helious.io.

MCP SERVER

Helious API pricing

Prices published by Helious, read 2026-11-11 from helious.io/pricing.

Plan	Price
Free	$0 free forever
Squawk	$99 a year
Starter	$14.99 a month
Pro	$39.99 a month
Ultimate	$99 a month

Plan details, limits and sources →

Pricing Plans 1

Published pricing tiers and plan structures.

Helious Plans Pricing

5 plans

PLANS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Helious Io Context

3 classes · 33 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs. Counts are the severity each rule declares, not results of running them.

Helious API Rules

64 rules · 57 error-severity 6 warn-severity 1 info-severity

SPECTRAL

JSON Schema 2

Standalone JSON Schema definitions for this provider's data models.

Envelope

6 properties

JSON SCHEMA

FeedItem

17 properties

JSON SCHEMA

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Helious Authentication

3 schemes

SECURITY

Helious Domain Security

TLSv1.3 · HSTS · DNSSEC · DMARC

SECURITY

Helious Vulnerability Disclosure

security.txt · contact published

SECURITY

Scopes 1

OAuth scopes governing access to this provider's APIs.

Helious Scopes

4 scopes · authorizationCode

4 scopes

SCOPES

Agentic Access (API Evangelist recommendations) 1

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

Helious Agentic Access

66 operations · 6 acting · 1 human-in-the-loop

66 operations · 6 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

APIReference

APIReference

Documentation

Documentation

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgentSkill

LLMsTxt

MCPServer

WellKnown

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

ErrorCatalog

Conformance

Access & Security 7

Authentication, authorization, and security posture

Security

Authentication

SecurityTxt

SecurityTxt

OAuthScopes

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Scroll for all 7

Operate 3

Status, limits, changes, and where to get help

StatusPage

StatusPage

Roadmap

Roadmap

Support

Support

Commercial 2

Pricing, plans, and the legal terms of use

Plans

Plans

Pricing

Pricing

Company 3

The organization behind the API

Newsroom

Newsroom

Blog

Blog

Website

Website

Other 3

Properties that don't map to a standard resource type

AgentCard

AgentCard

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: helious-io
name: Helious
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  gated: none
  gated_source:
  - onboarding
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-11-13'
  method: derived
image: https://helious.io/og-default.png?v=2
description: Helious provides a live US market news terminal delivering real‑time economic calendar events, Treasury auction
  results, and release forecasts. Users can view live squawk, score releases against consensus instantly, and track yield
  curves and Fed speaker commentary, all without a subscription card.
url: https://artifacts.apis.io/helious-io/apis.yml
x-type: company
x-source: harvest:mcp-registry
x-tier: profiled
x-tier-reason: enrichment pass 2026-11-11 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-11-11'
modified: '2026-11-11'
tags:
- Finance
- Market Data
- News
- Economic Calendar
- Treasury
tags_raw:
- Finance
- MarketData
- News
- EconomicCalendar
- Treasury
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: APIReference
  url: https://helious.io/developers/
- type: AgenticAccess
  url: agentic-access/helious-io-agentic-access.yml
- type: Plans
  url: plans/helious-io-plans-pricing.yml
- type: Spectral
  url: rules/helious-io-rules.yml
- type: JSONLD
  url: json-ld/helious-io-context.jsonld
- type: Vocabulary
  url: vocabulary/helious-io-vocabulary.yml
- type: AgentSkill
  url: skills/_index.yml
- type: DataModel
  url: data-model/helious-io-data-model.yml
- type: Security
  url: security/helious-io-vulnerability-disclosure.yml
- type: Authentication
  url: authentication/helious-io-authentication.yml
- type: ErrorCatalog
  url: errors/helious-io-problem-types.yml
- type: Conformance
  url: conformance/helious-io-conformance.yml
- type: LLMsTxt
  url: llms/helious-io-llms.txt
- type: AgentCard
  url: a2a/helious-io-a2a.yml
- type: MCPServer
  url: mcp/helious-io-mcp.yml
- type: SecurityTxt
  url: well-known/helious-io-security.txt
- type: SecurityTxt
  url: well-known/helious-io-helious-security.txt
- type: WellKnown
  url: well-known/helious-io-well-known.yml
- type: Hosts
  url: hosts/helious-io-hosts.yml
- type: Vendors
  url: vendors/helious-io-vendors.yml
- type: StatusPage
  url: https://helious.io/status
- type: Roadmap
  url: https://helious.io/roadmap
- type: Newsroom
  url: https://helious.io/news
- type: Blog
  url: https://helious.io/blog/
- type: DeveloperPortal
  url: https://api.helious.io</code
- type: OAuthScopes
  url: scopes/helious-io-scopes.yml
- type: VulnerabilityDisclosure
  url: security/helious-io-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/helious-io-domain-security.yml
- type: Website
  url: https://helious.io/
- type: Documentation
  url: https://helious.io/mcp
- type: GettingStarted
  url: https://helious.io/usage
- type: Support
  url: https://helious.io/contact
- type: Pricing
  url: https://helious.io/pricing
apis:
- aid: helious-io:helious-io-agent-sign-in-and-a2a-api
  name: Helious Agent sign-in and A2A API
  description: OAuth 2.1 so an agent can act for a person without a pasted key, and the agent-to-agent endpoint for asking
    the desk a question in plain words.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Agent sign-in and A2A
  properties:
  - type: OpenAPI
    url: openapi/helious-io-agent-sign-in-and-a2a-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-ask-helious-api
  name: Helious Ask Helious API
  description: The Ask Helious API from Helious — 1 operation(s) for ask helious.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Ask Helious
  properties:
  - type: OpenAPI
    url: openapi/helious-io-ask-helious-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-boards-api
  name: Helious Boards API
  description: 'The FX momentum, implied volatility, correlation and Hormuz boards: newest reading plus history.'
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Boards
  properties:
  - type: OpenAPI
    url: openapi/helious-io-boards-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-economic-data-api
  name: Helious Economic data API
  description: Every tracked US economic series, the calendar, and release prints with their surprise scores.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Economic Data
  tags_raw:
  - Economic data
  properties:
  - type: OpenAPI
    url: openapi/helious-io-economic-data-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-news-and-feed-api
  name: Helious News and feed API
  description: 'The Helious feed: the news wire and the desk''s own posts, each with a score for bonds and one for stocks.'
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - News and feed
  properties:
  - type: OpenAPI
    url: openapi/helious-io-news-and-feed-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-rates-and-curve-api
  name: Helious Rates and curve API
  description: Live Treasury yields, spreads, the curve regime and its history.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Rates and curve
  properties:
  - type: OpenAPI
    url: openapi/helious-io-rates-and-curve-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-reference-api
  name: Helious Reference API
  description: Glossary, the measured capture latency and supporting reference data.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Reference
  properties:
  - type: OpenAPI
    url: openapi/helious-io-reference-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-series-api
  name: Helious Series API
  description: The Series API from Helious — 2 operation(s) for series.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Series
  properties:
  - type: OpenAPI
    url: openapi/helious-io-series-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-the-fed-api
  name: Helious The Fed API
  description: FOMC meetings, the roster and upcoming speakers.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - The Fed
  properties:
  - type: OpenAPI
    url: openapi/helious-io-the-fed-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-the-squawk-api
  name: Helious The squawk API
  description: The The squawk API from Helious — 2 operation(s) for the squawk.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - The squawk
  properties:
  - type: OpenAPI
    url: openapi/helious-io-the-squawk-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-treasury-auctions-api
  name: Helious Treasury auctions API
  description: Auction results by tenor, with the tail against the when-issued yield.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Treasury auctions
  properties:
  - type: OpenAPI
    url: openapi/helious-io-treasury-auctions-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
- aid: helious-io:helious-io-your-key-api
  name: Helious Your key API
  description: What your key is and what it may do.
  humanURL: https://helious.io/developers/
  baseURL: https://api.helious.io
  tags:
  - Your key
  properties:
  - type: OpenAPI
    url: openapi/helious-io-your-key-api-openapi.yml
  - type: JSONSchema
    url: json-schema/helious-io-feed-item-schema.json
  - type: JSONSchema
    url: json-schema/helious-io-envelope-schema.json
x-enrichment:
  date: '2026-11-11'
  status: enriched
  artifacts_added: 45
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

Helious API — frequently asked questions

Does Helious have an API?

Yes. APIs.io lists 12 APIs from Helious, including Helious Agent sign-in and A2A API, Helious Ask Helious API and Helious Boards API, and 9 more.

Is there an OpenAPI specification for the Helious API?

Yes. APIs.io indexes 12 OpenAPI specifications for Helious, each linked for download from this page.

How do I authenticate with the Helious API?

Helious documents its authentication (3 schemes). The details are profiled on APIs.io as Helious Authentication.

How much does the Helious API cost?

Helious publishes its prices; its Free plan is $0 free forever as of 2026-11-11. APIs.io lists 5 pricing plans for Helious, with each plan's price, limits and inclusions under Pricing on this page.

Does Helious have an MCP server?

Yes. APIs.io lists 1 MCP server for Helious: Remote MCP server at helious.io.

Is the Helious API ready for AI agents?

Helious has a Kin Score of 51.4 out of 100 (developing) and an Agent Readiness score of 51.2 (agent-ready), scored by API Evangelist on 2026-11-13.

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