# NTT DOCOMO, Inc.

> Japan's largest mobile network operator (~90 million subscriptions, wholly
> owned by NTT). Generated by API Evangelist on 2026-07-25 from the
> ntt-docomo repository; NTT DOCOMO publishes no llms.txt of its own
> (/llms.txt returns 404 on www.docomo.ne.jp and id.smt.docomo.ne.jp, 403 on
> conf.uw.docomo.ne.jp).

## What an agent can and cannot do here

NTT DOCOMO, Inc. has **no self-serve developer portal, no API keys, no sandbox
and no OpenAPI definition**. Do not attempt to call a DOCOMO REST API — there
isn't one. The first-party "docomo Developer support" marketplace (opened
October 2013) shut down on 31 March 2021 and its host `dev.smt.docomo.ne.jp`
no longer resolves, so any code or documentation referencing it is dead.

Exactly two machine interfaces are publicly documented:

1. **d ACCOUNT Connect** — an OpenID Connect Provider for carrier identity.
   Its discovery document is anonymously readable; everything else requires a
   partner application and a DOCOMO review (審査).
2. **docomo Mail IMAP interface** — an IMAP protocol specification published
   as a Japanese PDF. Not an HTTP API.

DOCOMO's network APIs (CAMARA Number Verification, SIM Swap) are an
**announcement, not an implementation**: a partnership with the aggregator
Aduna was concluded 29 January 2026, but as of 2026-07-25 no endpoint,
specification, sandbox or credential path is published by DOCOMO, and DOCOMO
is not listed on Aduna's operator wall.

Enterprise and wholesale API demand belongs to a **different legal entity**:
`docomo.ne.jp/biz` redirects to `ntt.com` (NTT DOCOMO BUSINESS, Inc.), which
runs the group's real API gateway portal at developer.ntt.com. That is
profiled separately as `ntt-com` and is not NTT DOCOMO, Inc.'s surface.

## APIs

- [d ACCOUNT Connect](https://id.smt.docomo.ne.jp/src/index_business.html): OpenID Connect carrier identity for businesses — ~90 million d ACCOUNT registrations, ~2,000 implemented relying-party sites. Authorization code flow, pairwise subject identifiers, HS256/RS256 ID tokens.
- [docomo Mail IMAP interface](https://www.docomo.ne.jp/service/developer/smart_phone/application/imap/): IMAP client interface specification for docomo Mail, distributed as a 96-page Japanese PDF (revised 2026-01-26).

## Specs and machine-readable documents

- [OpenID Connect discovery document](https://conf.uw.docomo.ne.jp/.well-known/openid-configuration): HTTP 200, application/json, 541 bytes. The only anonymous machine-readable document DOCOMO publishes. Minimal — no scopes_supported, grant_types_supported, claims_supported or backchannel_authentication_endpoint.
- [JWKS](https://fr-end.oidc.if.cilite.docomo.ne.jp/oft/external/ofrnt/v1.0/jwksget): HTTP 200, one RSA signing key.
- [docomo Mail IMAP Interface Specification (PDF)](https://www.docomo.ne.jp/binary/pdf/service/developer/smart_phone/application/imap/mail_imap_spec_260126.pdf): 96 pages, 1,229,737 bytes, revised 2026-01-26.
- No OpenAPI, Swagger, AsyncAPI, GraphQL schema, .proto or Postman collection exists on any NTT DOCOMO, Inc. host.

## Docs

- [開発者向け情報 (developer information)](https://www.docomo.ne.jp/service/developer/): The one surviving public developer page. Open, no registration — but handset and content technical information (Machi-Chara, Deco-mail, emoji, NFC/Osaifu-Keitai, docomo Mail downloader and IMAP, device spec list, sp-mode server IP ranges), not an API portal.
- [開発者向け情報ご利用にあたって (terms of use)](https://www.docomo.ne.jp/service/developer/policy/index.html)
- [d ACCOUNT Connect — 導入方法 (implementation method)](https://id.smt.docomo.ne.jp/src/dlogin/ctop_method.html): The six-step onboarding, the two attribute-release tiers, and the fee model.
- [d ACCOUNT Connect maintenance information](https://id.smt.docomo.ne.jp/src/dac/maintenance-g.html)
- [重要なお知らせ（通信障害等） — network incident notices](https://www.docomo.ne.jp/info/network/)

## Onboarding

Self-serve is not possible. The path is:

1. Create a d ACCOUNT: https://id.smt.docomo.ne.jp/cgi8/id/register
2. Apply on the d ACCOUNT Connect application site (company + applicant details); DOCOMO reviews and replies by email in ~3 business days: https://g.daccount.docomo.ne.jp/VIEW_OC01/login4
3. Download the integration manual, technical specification and support libraries (released only after approval).
4. Register the service and relying-party configuration; connection is enabled after a second ~3-business-day approval.
5. Implement, then go live.

Attribute release is tiered: **login only** returns a user identifier, with no
conditions and no fee. **Login + user information** requires a DOCOMO review
and a third-party certification (第三者認証の取得); email address is free, while
name, date of birth and other customer information are paid, and the
registration/annual fee is waived for d POINT / d払い member merchants.

Carrier billing (d払い / d Payment) has no public merchant API — merchants
integrate through payment-gateway partners such as GMO Payment Gateway,
PAYGENT and SB Payment Service.

## API Evangelist artifacts in this repository

- [apis.yml](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/apis.yml)
- [Authentication profile](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/authentication/ntt-docomo-authentication.yml)
- [Well-known index](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/well-known/ntt-docomo-well-known.yml)
- [OpenID configuration (saved verbatim)](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/well-known/ntt-docomo-openid-configuration.json)
- [JWKS (saved verbatim)](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/well-known/ntt-docomo-jwks.json)
- [Conventions](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/conventions/ntt-docomo-conventions.yml)
- [Conformance](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/conformance/ntt-docomo-conformance.yml)
- [Lifecycle](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/lifecycle/ntt-docomo-lifecycle.yml)
- [Packages](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/packages/ntt-docomo-packages.yml)
- [Domain security](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/security/ntt-docomo-domain-security.yml)
- [Review](https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/review.yml)

## Not published (verified absent, 2026-07-25)

- OpenAPI / Swagger — probed /openapi.json, /openapi.yaml, /swagger.json, /v1/openapi.json, /api-docs, /docs, /redoc on conf.uw.docomo.ne.jp, id.smt.docomo.ne.jp, service.smt.docomo.ne.jp and www.docomo.ne.jp: all 403 or 404.
- GraphQL, gRPC/.proto, AsyncAPI, webhooks, MCP server, agent skills.
- security.txt, api-catalog, ai-plugin.json, vulnerability disclosure programme, bug bounty, trust center, named certifications.
- First-party SDKs on npm, PyPI, Maven Central or NuGet; github.com/docomo has zero public repositories.
- Public Postman workspace or collection.
- Rate-limit policy, SLA, changelog, roadmap, CLI, embedded components.