generated: '2026-07-25' method: searched source: >- well-known/ntt-docomo-openid-configuration.json (live, HTTP 200, fetched 2026-07-25); https://id.smt.docomo.ne.jp/src/dlogin/ctop_method.html; https://id.smt.docomo.ne.jp/src/index_business.html; https://www.docomo.ne.jp/service/developer/smart_phone/application/imap/ description: >- Cross-cutting runtime semantics for NTT DOCOMO, Inc.'s public interfaces. There is no REST API here, so most of the conventions this artifact usually captures — idempotency, pagination, expansion, metadata, request tracing, an error envelope, rate-limit signalling — genuinely do not exist rather than being undocumented. What does exist is a federated-identity protocol contract (OpenID Connect authorization code) and a mail protocol contract (IMAP). Both are recorded here so an agent knows exactly what shape of interaction is possible and where the boundary sits. api_style: >- No REST/HTTP API surface. Two protocol interfaces: OpenID Connect (browser-redirect authorization code flow) and IMAP over TLS. surfaces: - name: d ACCOUNT Connect protocol: OpenID Connect over HTTPS issuer: https://conf.uw.docomo.ne.jp/ interaction: >- Browser redirect to the authorization endpoint, code exchange at the token endpoint, claim retrieval at the userinfo endpoint. There is no programmatic resource API behind it — the relying party receives identity assertions, not data endpoints. detail: authentication/ntt-docomo-authentication.yml - name: docomo Mail IMAP interface protocol: IMAP over TLS (IMAPS) interaction: >- Standard IMAP client session against the docomo Mail server. Specified in ドコモメール IMAP インターフェース仕様書 第4.5版, 2026-01-26 — a 96-page Japanese PDF (mail_imap_spec_260126.pdf, 1,229,737 bytes) published openly with no registration. This is the one complete, unredacted machine-interface contract NTT DOCOMO, Inc. publishes. docs: https://www.docomo.ne.jp/service/developer/smart_phone/application/imap/ spec_pdf: https://www.docomo.ne.jp/binary/pdf/service/developer/smart_phone/application/imap/mail_imap_spec_260126.pdf spec_version: '4.5' spec_date: '2026-01-26' spec_first_edition: '2013-12-19' endpoints: - host: imap.spmode.ne.jp port: 993 note: General endpoint — used by all clients other than the iOS standard mailer. - host: imap2.spmode.ne.jp port: 993 note: >- Used when configuring the standard iPhone/iPad mailer. Behaviour differs from imap.spmode.ne.jp: this endpoint rewrites multipart structure so Deco-mail pictures are not treated as attachments, and transcodes i-mode pictographs to Unicode emoji in display names, subject, body and attachment filenames (returned message size reflects the transcoded size, except in GETQUOTAROOT/GETQUOTA). credentials: d ACCOUNT ID and password transport_security: tls_version: TLS 1.2 server_authentication: certificate-based public_key_length: 2048-bit cipher_suites: - RSA_WITH_AES_128_CBC_SHA - RSA_WITH_AES_256_CBC_SHA - RSA_WITH_3DES_EDE_CBC_SHA - RSA_WITH_AES_128_CBC_SHA256 - RSA_WITH_AES_256_CBC_SHA256 - TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 note: Cipher suites other than those listed are not accepted. commands_specified: - LOGIN - AUTHENTICATE - LOGOUT - SELECT - EXAMINE - CREATE - DELETE - RENAME - SUBSCRIBE - UNSUBSCRIBE - LIST - LSUB - STATUS - CHECK - CLOSE - APPEND - EXPUNGE - SEARCH - FETCH - STORE - COPY - UID - UID EXPUNGE - CAPABILITY - NOOP - IDLE - NAMESPACE - GETQUOTAROOT - GETQUOTA - SETQUOTA - ID unsupported_command_behaviour: >- Section 3.1.11 specifies the server response returned to a client that issues an out-of-scope or unsupported command — the closest thing DOCOMO publishes to a documented error contract on any interface. authentication: scheme: OpenID Connect authorization code (response_type=code) subject_identifier: pairwise — each relying party receives a different sub for the same user id_token_signing: HS256 or RS256 client_credentials: >- Issued only after DOCOMO's application and review process; no self-serve key issuance exists anywhere on docomo.ne.jp. detail: authentication/ntt-docomo-authentication.yml idempotency: supported: false mechanism: null notes: >- No idempotency-key header, parameter or contract is documented. There is no write API to make idempotent — the OIDC surface is authorization-code exchange only. No `Idempotency` pointer is emitted. pagination: supported: false notes: No collection endpoints are published, so no pagination contract exists. field_expansion: supported: false notes: >- Attribute release is tiered commercially rather than by request parameter: the login-only tier returns a user identifier; the login-plus-user-information tier adds email address (free) and name, date of birth and other customer information (paid). Selection happens at contract time, not at request time. metadata: supported: false request_tracing: request_id_header: null notes: >- No documented correlation header. The OIDC issuer host does return an apigw-requestid and CloudFront x-amz-cf-id on responses (it sits behind AWS API Gateway and CloudFront), but DOCOMO does not document either as a support-traceable identifier. versioning: scheme: none-published notes: >- No version segment in the OIDC endpoint paths and no version member in the discovery document. detail: lifecycle/ntt-docomo-lifecycle.yml error_envelope: media_type: null rfc9457: false notes: >- No error catalogue is published. OIDC/OAuth 2.0 protocol errors would be the RFC 6749 error/error_description query parameters by specification, but DOCOMO documents no error list of its own, so no errors/ artifact is emitted rather than reproducing the RFC as if it were DOCOMO's contract. rate_limits: documented: false signal_status: null notes: No rate-limit policy, headers or 429 contract are published. webhooks: supported: false notes: >- No event, callback or webhook surface. Back-channel logout is not advertised (no end_session or backchannel_logout metadata). sandbox: available: false notes: >- No sandbox, test tenant or magic test identifier is published. Integration testing happens against production after DOCOMO approves the relying-party registration. gating: self_serve: false review_required: true review_turnaround: ~3 business days per approval stage notes: >- The dominant convention of this provider is the gate itself. Two separate reviews sit between a developer and a working integration — one on company and applicant registration, one on service and relying-party configuration — and the technical manual is only released between them. detail: authentication/ntt-docomo-authentication.yml cross_reference: authentication: authentication/ntt-docomo-authentication.yml lifecycle: lifecycle/ntt-docomo-lifecycle.yml conformance: conformance/ntt-docomo-conformance.yml well_known: well-known/ntt-docomo-well-known.yml domain_security: security/ntt-docomo-domain-security.yml