# docomo Mail IMAP Interface

**Canonical:** https://apis.io/apis/ntt-docomo/docomo-mail-imap-interface/  
**Provider:** NTT Docomo — https://apis.io/providers/ntt-docomo/  
**Base URL:** imaps://imap.spmode.ne.jp:993  
**Documentation:** https://www.docomo.ne.jp/service/developer/smart_phone/application/imap/

docomo Mail IMAP Interface is one of 2 APIs that [NTT Docomo](https://apis.io/providers/ntt-docomo/) publishes on the [APIs.io](https://apis.io/) network. Tagged areas include Email, IMAP, Protocol, and Specification. The published artifact set on APIs.io includes API documentation and an API reference.

The docomo Mail IMAP interface is the one machine-interface specification NTT DOCOMO publishes openly, without registration, to third-party developers. It documents how a mail client connects to the docomo Mail service over IMAP, and is distributed as a 96-page Japanese PDF specification (mail_imap_spec_260126.pdf, HTTP 200, application/pdf, 1,229,737 bytes, edition 4.5 dated 2026-01-26, first edition 2013-12-19). This is an IMAP protocol interface, not an HTTP API: there is no REST surface, no OpenAPI definition, no API key issuance and no sandbox associated with it. The specification is complete and unredacted — it names the two production endpoints (imap.spmode.ne.jp and imap2.spmode.ne.jp, both on port 993), pins TLS 1.2 with an explicit allow-list of ten cipher suites and a 2048-bit public key, authenticates with d ACCOUNT ID and password, and specifies 31 IMAP commands including IDLE, NAMESPACE, UID EXPUNGE and the QUOTA family. The imap2 endpoint exists for the standard iPhone/iPad mailer and deliberately differs in behaviour, rewriting multipart structure for Deco-mail pictures and transcoding i-mode pictographs to Unicode emoji.

## Machine-readable artifacts (3)

- **Documentation** — https://www.docomo.ne.jp/service/developer/smart_phone/application/imap/
- **APIReference** — https://www.docomo.ne.jp/binary/pdf/service/developer/smart_phone/application/imap/mail_imap_spec_260126.pdf
- **Conventions** — https://raw.githubusercontent.com/api-evangelist/ntt-docomo/refs/heads/main/conventions/ntt-docomo-conventions.yml

## Other NTT Docomo APIs (1)

- [d ACCOUNT Connect](https://apis.io/apis/ntt-docomo/d-account-connect/)

## Tags

Email, IMAP, Protocol, Specification

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/ntt-docomo/docomo-mail-imap-interface/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/ntt-docomo/.