Kyash

Kyash Inc. (株式会社Kyash) is a Tokyo-based fintech founded in 2015 that operates a consumer mobile wallet and Visa prepaid card in Japan, covering charging, peer-to-peer transfers, shared accounts, buy-now-pay-later, personal finance management, and contactless payment through Apple Pay, Google Pay, and Samsung Pay. Kyash is a registered Funds Transfer Service Provider (Kanto Local Finance Bureau No. 00082) and a third-party Prepaid Payment Instrument Issuer (No. 00698), and is ISO/IEC 27001:2022, PCI DSS, and TRUSTe certified. Its business-facing product is Kyash Payout, a mass payout service that sends funds to Japanese domestic bank accounts or Kyash wallets at a flat 50 yen per transfer, integrated either by Zengin/CSV file upload or by direct API integration including a balance API. Kyash previously sold Kyash Direct, an API-based Visa card issuer processing platform launched in 2019. All API access is sales-gated: Kyash publishes no developer portal, API reference, specification, SDK, or sandbox.

Kyash is profiled on the APIs.io network. Tagged areas include Company, Financial Services, Payments, Fintech, and Digital Wallet.

Kyash’s developer surface includes engineering blog, support, pricing, signup flow, product news, and 16 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

21.2/100 emerging ▬ flat Agent 0/100 human only Front door AI 1/6 silent Heartbeat 24/100 slowing saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

0 APIs

Company Financial Services Payments Fintech Digital Wallet Prepaid Cards Money Transfer Payouts Japan Visa

Kin Score

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

Composite quality — 21.2/100 · emerging

Contract Quality 0.0 / 21

Developer Ergonomics 1.2 / 17

Access Clarity 10.3 / 17

Operational Transparency 2.0 / 11

Contract Governance 0.0 / 10

Discoverability 4.8 / 9

Regulatory Posture 2.6 / 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 Payments 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
Contract Governance scores 0.0 — up to +12.0 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/kyash/apis.yml: open an issue on github.com/api-evangelist/kyash 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 →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Japan FSA Registered Fintech (crypto exchanges, stablecoin intermediaries, funds transfer, bank-API agents, prepaid)	regulated	47.9	-	-

Registered MCP server and declares compatibility are report only — not weighted. Undeclared means we found nothing we can read, so there is no number: we never infer integrations.

Security Posture 2

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

Kyash Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Kyash Trust Center

ISO/IEC 27001:2022, PCI DSS, TRUSTe

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp

SignUp

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

LLMsTxt

LLMsTxt

Design & Contract 1

Pagination, idempotency, versioning, errors, and events

Lifecycle

Lifecycle

Build 2

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

GitHubOrganization

Packages

Packages

Access & Security 3

Authentication, authorization, and security posture

Compliance

Compliance

TrustCenter

TrustCenter

DomainSecurity

DomainSecurity

Operate 4

Status, limits, changes, and where to get help

Support

HelpCenter

StatusPage

ContactUs

Commercial 3

Pricing, plans, and the legal terms of use

Pricing

Pricing

TermsOfService

TermsOfService

PrivacyPolicy

PrivacyPolicy

Company 5

The organization behind the API

Website

Blog

BlogRSS

News

Careers

Other 1

Properties that don't map to a standard resource type

Company

Company

Source (apis.yml)

aid: kyash
name: Kyash
description: 'Kyash Inc. (株式会社Kyash) is a Tokyo-based fintech founded in 2015 that operates a consumer mobile wallet and Visa
  prepaid card in Japan, covering charging, peer-to-peer transfers, shared accounts, buy-now-pay-later, personal finance management,
  and contactless payment through Apple Pay, Google Pay, and Samsung Pay. Kyash is a registered Funds Transfer Service Provider
  (Kanto Local Finance Bureau No. 00082) and a third-party Prepaid Payment Instrument Issuer (No. 00698), and is ISO/IEC 27001:2022,
  PCI DSS, and TRUSTe certified. Its business-facing product is Kyash Payout, a mass payout service that sends funds to Japanese
  domestic bank accounts or Kyash wallets at a flat 50 yen per transfer, integrated either by Zengin/CSV file upload or by
  direct API integration including a balance API. Kyash previously sold Kyash Direct, an API-based Visa card issuer processing
  platform launched in 2019. All API access is sales-gated: Kyash publishes no developer portal, API reference, specification,
  SDK, or sandbox.'
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: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - security
  generated: '2026-11-06'
  method: derived
image: https://cdn.prod.website-files.com/5db15c3bca3871afff172c17/5e999e9506f3ea01ffabcdbb_kyash_logo_symbol_blue.png
url: https://raw.githubusercontent.com/api-evangelist/kyash/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- partech
x-tier: profiled
x-tier-reason: enriched-no-public-api-surface
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-07-25'
tags:
- Company
- Financial Services
- Payments
- Fintech
- Digital Wallet
- Prepaid Cards
- Money Transfer
- Payouts
- Japan
- Visa
tags_raw:
- Company
- Financial Services
- Payments
- Fintech
- Digital Wallet
- Prepaid Cards
- Money Transfer
- Payouts
- Japan
- Visa
- Financial-Services
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://kyash.co/
- type: Blog
  url: https://blog.kyash.co/
- type: BlogRSS
  url: https://blog.kyash.co/feed
- type: Support
  url: https://help.kyash.co/
- type: HelpCenter
  url: https://help.kyash.co/
- type: GitHubOrganization
  url: https://github.com/Kyash
- type: Pricing
  url: https://kyash.co/biz/payout
- type: SignUp
  url: https://kyash.co/biz/payout/inquiry
- type: TermsOfService
  url: https://kyash.co/legal/terms
- type: PrivacyPolicy
  url: https://kyash.co/legal/policy/privacy
- type: Compliance
  url: https://kyash.co/legal/policy/security
- type: TrustCenter
  url: security/kyash-trust-center.yml
- type: DomainSecurity
  url: security/kyash-domain-security.yml
- type: Lifecycle
  url: lifecycle/kyash-lifecycle.yml
- type: StatusPage
  url: https://kyash.co/news/maintenance
- type: Packages
  url: packages/kyash-packages.yml
- type: LLMsTxt
  url: llms/kyash-llms.txt
- type: News
  url: https://kyash.co/news/press-release
- type: Company
  url: https://kyash.co/company
- type: Careers
  url: https://kyash.co/recruit
- type: ContactUs
  url: https://kyash.co/contact
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence

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