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RAIN Alliance Documents

RAIN URI Template list (RUTlist)

RAIN-RUT-001 Version 2026-09-25 25 September 2026

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The RAIN URI Template list maps the RUTselector encoded on a tag to the URI template it stands for, so that a reader can rebuild the whole URI from what the tag carries. It is referenced by the RAIN URI Identifier specification, which ISO/IEC 15961 approved along with an AFI and DSFID assignment, and publication and maintenance of the list sits with the RAIN Alliance under that approval. The list is not standalone: the encoding rules and the worked examples are in that specification.

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Always the current edition. This address does not change when a new version is published, so it is the one to give to software.

Always this edition, under the name it was issued with. Cite this where the exact text matters, and it will go on serving these words after a newer version exists.

The templates

Issued 25 September 2026. This table is generated from the published file above, so the two cannot disagree. Encode against the file.

RAIN URI Templates, by RUTselector, with the instructions that apply to each.
RUTselector RUT Instructions
0 https://*?*
  • The second * can be empty.
  • When the first * is in UII, then the second * can be in either UII or UserMem.
1 https://doi.org/*?*
  • The second * can be empty.
  • The first * must be in UII. The second * can be in either UII or UserMem.
2 https://*/did:ethr:*0x{UIIserial}?* UIIserial is the hex encoded in the last data element of UII following the [STE].
3 https://*/did:*?service=* The third * can be empty. The third * can be in UserMem.
4 https://*-id.therainalliance.io?*
  • This RUT uses DNS hostname aliasing ensuring direct access to the resolver using DNS. Please contact the RAIN Alliance for options.
  • This RUT also facilitates a 32-bit URL-Add-on encoded in UserMem, where the first * is limited to two characters.
  • E.g. Example Inc. encodes 'ab' -> URL: 'https://ab-id.therainalliance.io?RAIN_AFI=..&RAIN_UII=...&RAIN_TID=...'
  • With the appropriate DNS ALIAS 'https://ab-id.therainalliance.io' is translated to, say 'https://example_inc.com' which directly accesses the DPP.
  • The second * can be empty.
5 did:*?service=* The second * can be empty. The second * can be in UserMem.

Notes on encoding

  • MB01 uses a 6-bit lowercase character set. RUTvalues encoded in MB01 shall therefore use lowercase characters or identify URI components that are case-insensitive.
  • MB11 uses UTF-8. UTF-8 character encodings can be one to four bytes.
  • RUTselectors 64 to 255 can only be used in Add-on mode.
  • In Identifier mode, RAIN_serial is the encoded UIIserial when present; otherwise, it is the TID serialisation.
  • RAIN_serial is added as a query key unless the RUT maps it using {RAIN_serial}.
  • In Add-on mode, RAIN_AFI is always added as a query key. RAIN_UII is added as a query key unless the RUT maps it using {RAIN_UII}.
  • The {RAIN_UII} placeholder can only be used in Add-on mode.
  • Where fewer RUTvalues are encoded than the number of variable fields in the selected RUT, each missing trailing RUTvalue shall be interpreted as an empty string.

About this document

This edition was issued on 25 September 2026 and carries six templates, RUTselectors 0 to 5. The table on this page is generated from the published JSON, so the readable list and the machine-readable one cannot disagree.

Two addresses serve the file. /document/RAIN_URI_Encoding_RUTlist_20260925.json is where this edition is published, and it will serve this edition for good. /document/rain-rut-001.json always serves whatever edition is current, and is the address to build into software that should follow the list forward.

The RUT format, the encoding rules and the worked examples are in the RAIN URI Identifier specification, under References below. The list cannot be implemented from this page alone.

References

Implementing this document

To reach the workgroup that wrote it, or to raise something that needs clarifying, email [email protected].