3DS ReferenceProtocol & field guide

EMV 3-D Secure · Core specification 2.3.1.1

Operation SequenceopSeq

Operation Sequence in Operation Request (OReq).

Source edition: Core 2.3.1.1 · Type: Object

Baseline in OReq Required

Baseline from the published source; transaction-context evaluation is unavailable for this field. Usage and conditions ↓

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Usage in OReq

Indicates the current and total messages in an OReq message sequence. This element seqId: uniquely identifies a message sequence and will remain constant in the sequence of messages. This element seqNum: represents the current message in the sequence. This element seqTotal: represents the total number of messages in the sequence and will remain constant in the sequence of messages.

Format and scope

Type: Object

Source components: DS. Channels: Not specified. Categories: Not specified.

Object members

Nested presence rules apply when the parent is supplied. Consult the source for full conditions.

opPriorTransRef — Operation Prior

EMV_3DS_CoreSpec_v2.3.1.1_20230530.pdf, Table A.1, PDF pages 269

Scoped FAQ qualifications

  • FAQ 27 — Applicable object-bearing protocol versions

    Only when the parent JSON object is present

    Evaluate nested presence conditions when the parent object is present. In multiTransaction, merchantList is required when the object is supplied; merchantAmount remains optional.

    EMVCo_3DS_Specification_FAQs_8-April-2026.pdf, page 9

  • FAQ 73 — Applicable object-bearing protocol versions

    An optional or conditionally optional field is sent empty

    An empty optional field produces error 203 under Req 309. When the empty JSON object contains mandatory data, error 201 may be returned.

    EMVCo_3DS_Specification_FAQs_8-April-2026.pdf, page 23

Transaction context

This reference covers the published source edition. Use the explorer to inspect this field and any applicable transaction conditions. Scheme programme requirements are not inferred from the protocol edition.

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Sources and related references

EMV_3DS_CoreSpec_v2.3.1.1_20230530.pdf, Table A.1, PDF pages 269

Source review status: carried-forward. Carried-forward material has not acquired a new verification claim.

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