Hallo

Hallo is an AI-powered language assessment and language-learning company backed by Battery Ventures. Its enterprise platform delivers automated, AI-driven proficiency assessments across speaking, writing, listening, and reading in 80+ languages, with CEFR-aligned scoring, detailed feedback (fluency, vocabulary, grammar, pronunciation, coherence), real-time score reports and dashboards, and proctoring / anti-cheating for high-stakes hiring, placement testing, and employee development. Hallo integrates with major applicant-tracking systems (Greenhouse, Ashby, Workday, SmartRecruiters, Lever, SuccessFactors, Recruitee, and others) and runs assessments across 160+ countries, with a stated SOC 2 Type 2, ISO 27001, GDPR, and EU AI Act compliance posture. The company also operates a consumer language-learning app with AI tutors and native-speaker practice. Hallo does not publish a public developer API or OpenAPI specification; its integration surface is delivered through prebuilt ATS connectors and enterprise onboarding rather than a self-serve developer portal.

Hallo is profiled on the APIs.io network. Tagged areas include Company, Language Assessment, Language Learning, Artificial Intelligence, and Recruiting.

Hallo’s developer surface includes pricing, signup flow, engineering blog, support, and 8 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

25.8/100 emerging ▬ flat Agent 0/100 human only Front door AI 6/6 dominant Heartbeat 100/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

0 APIs

CompanyLanguage AssessmentLanguage Learning Artificial Intelligence Recruiting Human Resources Education Speech Recognition

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 25.8/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 1.2 / 17

Access Clarity 14.3 / 17

Operational Transparency 0.0 / 11

Contract Governance 1.9 / 10

Discoverability 4.1 / 9

Regulatory Posture 3.3 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Education & Research 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):

Machine-Readable Contract +18 pts — api_specs includes an OpenAPI document
MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Agentic Access Contract +10 pts — agentic_access artifact present (x-agentic-access), graded by author
Machine-Readable Auth +10 pts — a served openid-configuration/oauth-authorization-server carrying `issuer` (served), else the securitySchemes class in the provider OpenAPIs — bound (mutualTLS, DPoP, Signature) > negotiable (oauth2 authorizationCode/clientCredentials, openIdConnect) > bearer (http bearer, apiKey)
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)
Stable Error Semantics +8 pts — OpenAPI $refs a shared error schema across 4xx/5xx responses (verified), else common[].type includes ErrorCatalog / ErrorCodes / DeclineCodes

13 more unmet checks in the Agent Readiness table above.

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

Contract Quality scores 0.0 — up to +25.0 composite points
Developer Ergonomics scores 7.1 — up to +18.6 composite points
Operational Transparency scores 0.0 — up to +13.0 composite points

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.

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/hallo/apis.yml: open an issue on github.com/api-evangelist/hallo 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 →

Hallo API pricing

Prices published by Hallo, read 2026-10-07 from hallo.ai/pricing/.

Plan	Price
Team	Custom Pricing Includes: AI-powered speaking, writing, reading, and/or listening assessments; 90+ languages; Dashboard; Insta
Business	Custom Pricing Includes: Everything in Team, plus API access, ATS integration, usage analytics
Enterprise	Custom Pricing Includes: Everything in Business, plus test customization, sub-organizations, SSO, dedicated CS manager

Plan details, limits and sources →

Pricing Plans 1

Published pricing tiers and plan structures.

Hallo Plans Pricing

3 plans

PLANS

Security Posture 1

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

Hallo Domain Security

TLSv1.3 · DMARC

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp

SignUp

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Conformance

Conformance

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Compliance

Compliance

Operate 1

Status, limits, changes, and where to get help

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 3

The organization behind the API

Website

Website

Blog

Blog

LinkedIn

Source (apis.yml)

aid: hallo
name: Hallo
description: Hallo is an AI-powered language assessment and language-learning company backed by Battery Ventures. Its enterprise
  platform delivers automated, AI-driven proficiency assessments across speaking, writing, listening, and reading in 80+ languages,
  with CEFR-aligned scoring, detailed feedback (fluency, vocabulary, grammar, pronunciation, coherence), real-time score reports
  and dashboards, and proctoring / anti-cheating for high-stakes hiring, placement testing, and employee development. Hallo
  integrates with major applicant-tracking systems (Greenhouse, Ashby, Workday, SmartRecruiters, Lever, SuccessFactors, Recruitee,
  and others) and runs assessments across 160+ countries, with a stated SOC 2 Type 2, ISO 27001, GDPR, and EU AI Act compliance
  posture. The company also operates a consumer language-learning app with AI tutors and native-speaker practice. Hallo does
  not publish a public developer API or OpenAPI specification; its integration surface is delivered through prebuilt ATS connectors
  and enterprise onboarding rather than a self-serve developer portal.
url: https://raw.githubusercontent.com/api-evangelist/hallo/refs/heads/main/apis.yml
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: false
  label: Hosted service · you call their endpoint
  confidence: medium
  source:
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: low
  source:
  - plans
  - security
  generated: '2026-11-06'
  method: derived
image: https://www.hallo.ai/wp-content/uploads/Hallo@3x.png
x-type: company
x-source: vc-portfolio
x-backed-by:
- battery-ventures
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-19'
tags:
- Company
- Language Assessment
- Language Learning
- Artificial Intelligence
- Recruiting
- Human Resources
- Education
- Speech Recognition
apis: []
common:
- type: Plans
  url: plans/hallo-plans-pricing.yml
- type: DomainSecurity
  url: security/hallo-domain-security.yml
- type: Website
  url: https://www.hallo.ai/
- type: Pricing
  url: https://www.hallo.ai/pricing/
- type: SignUp
  url: https://www.hallo.ai/demo/
- type: TermsOfService
  url: https://www.hallo.ai/terms-of-service/
- type: PrivacyPolicy
  url: https://www.hallo.ai/privacy-policy/
- type: Blog
  url: https://www.hallo.ai/blog/
- type: Support
  url: https://www.hallo.ai/contact/
- type: Integrations
  url: https://www.hallo.ai/integrations/
- type: LinkedIn
  url: https://www.linkedin.com/company/hallo.
- type: Conformance
  url: conformance/hallo-conformance.yml
- type: Compliance
  url: conformance/hallo-conformance.yml
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

Hallo API — frequently asked questions

How much does the Hallo API cost?

Hallo publishes its prices; its Team plan is Custom Pricing as of 2026-10-07. APIs.io lists 3 pricing plans for Hallo, with each plan's price, limits and inclusions under Pricing on this page.

Is the Hallo API ready for AI agents?

Hallo has a Kin Score of 25.8 out of 100 (emerging) and an Agent Readiness score of 0.0 (human-only), scored by API Evangelist on 2026-11-06.

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