> ## Documentation Index > Fetch the complete documentation index at: https://developers.ingopayments.com/llms.txt > Use this file to discover all available pages before exploring further. # Party Session Initiated > Fired once when a party opens their Digital Payment Center session. Carries details of the browser request that started the session, so you can correlate the session with your own fraud and analytics signals. ## AsyncAPI ````yaml specs/asyncapi-notify-v4.yaml TransactionPartySessionInitiated id: TransactionPartySessionInitiated title: Party Session Initiated description: >- Fired once when a party opens their Digital Payment Center session. Carries details of the browser request that started the session, so you can correlate the session with your own fraud and analytics signals. servers: - id: webhook protocol: https host: your-webhook-endpoint.example.com bindings: [] variables: [] address: transaction.party.session.initiated parameters: [] bindings: [] operations: - &ref_0 id: receiveTransactionPartySessionInitiated title: Receive transaction party session initiated description: Party Session Initiated type: receive messages: - &ref_1 id: TransactionPartySessionInitiatedMessage contentType: application/json payload: - name: Party Session Initiated type: object properties: - name: metadata type: object description: Delivery metadata present on every webhook event. required: true properties: - name: id type: string description: >- Ingo-assigned unique ID for this delivery. Use as your idempotency key to deduplicate retries. required: true - name: topic type: string description: Topic name identifying the event type. required: true - name: topic_description type: string description: Human-readable description of the event. required: true - name: timestamp type: integer description: Unix timestamp of the webhook delivery. required: true - name: version type: string description: Payload contract version. required: true - name: data type: object required: true properties: - name: ancillary type: object required: true properties: - name: notification_id type: string description: >- Ingo-assigned unique identifier for the staged notification. required: true - name: session_id type: string description: Ingo-assigned session identifier, when applicable. required: false - name: participant_unique_id1 type: string description: >- Your primary correlation ID from the original Notify request. required: true - name: participant_unique_id2 type: string description: Your optional secondary correlation ID. required: false - name: party_id type: string description: >- Ingo-assigned ID for the specific party this event relates to. Present on multi-party (Notify v4) events. required: false - name: tracer_token type: string description: >- Ingo-assigned tracer identifier for the original request. Optional. required: false - name: event type: object required: true properties: - name: status type: string description: Numeric status code for the event outcome. required: true - name: client_message type: string description: Human-readable description of the event outcome. required: true - name: attempt_count type: integer description: >- Current delivery attempt number. Present when the event type has a configurable attempt counter. required: false - name: max_attempts type: integer description: >- Maximum allowed attempts. Present when the event type has a configurable attempt counter. required: false - name: session_data type: object description: >- Details of the browser request that started the party's session. The event fires once per session, so these fields describe the entry request only. Every field is always present; a field with no value is sent as an empty string. required: true properties: - name: timestamp_date type: string description: UTC date of the entry request, `YYYY-MM-DD`. required: true - name: timestamp_time type: string description: >- UTC time of the entry request, `HH:MM:SS`. May include fractional seconds. required: true - name: cs_method type: string description: >- HTTP method of the entry request (for example `GET`). required: true - name: cs_uri_stem type: string description: >- Path of the entry request, without the query string. required: true - name: cs_uri_query type: string description: >- Query string of the entry request. Truncated at 450 characters. required: true - name: cs_host type: string description: Host name the party's browser requested. required: true - name: cs_referer type: string description: >- Referring page, from the browser's `Referer` header. Empty when the party opened the link directly. Truncated at 450 characters. required: true - name: cs_user_agent type: string description: Browser `User-Agent` string. required: true - name: accept_language type: string description: Browser `Accept-Language` header. required: true - name: client_ip type: string description: >- IP address of the party's device as seen at Ingo's network edge, IPv4 or IPv6. required: true - name: edge_request_id type: string description: >- Request identifier assigned at Ingo's network edge, including the edge location. Quote it to Ingo Support when asking about a specific session. required: true - name: ip_country type: string description: >- Country of `client_ip`, ISO 3166-1 alpha-2. `XX` when the country can't be determined. required: true - name: client_scheme type: string description: >- Original protocol of the entry request (`http` or `https`). required: true - name: sec_ch_ua type: string description: >- Browser brand list with major versions, from the `Sec-CH-UA` client hint (for example `"Chromium";v="126", "Google Chrome";v="126"`). Chromium-based browsers only; empty otherwise. required: true - name: sec_ch_ua_mobile type: string description: >- Mobile indicator, from the `Sec-CH-UA-Mobile` client hint (`?1` mobile, `?0` desktop). Chromium-based browsers only; empty otherwise. required: true - name: sec_ch_ua_platform type: string description: >- Operating system family, from the `Sec-CH-UA-Platform` client hint (for example `"Windows"`, `"Android"`, `"macOS"`). Family only, no version. Chromium-based browsers only; empty otherwise. required: true - name: sec_fetch_site type: string description: >- How the session started, from the `Sec-Fetch-Site` header: `none` = the party opened the link from an email, text message or bookmark; `cross-site` = the party arrived from another website; `same-origin` = navigation within the session site. Chromium-based browsers only; empty otherwise. required: true headers: [] jsonPayloadSchema: type: object required: - metadata - data properties: metadata: type: object required: - id - topic - topic_description - timestamp - version description: Delivery metadata present on every webhook event. properties: id: type: string maxLength: 50 description: >- Ingo-assigned unique ID for this delivery. Use as your idempotency key to deduplicate retries. example: prod01-6aaa3079-c1ff-4cae-b77a-4b76026fc846 x-parser-schema-id: topic: type: string maxLength: 150 description: Topic name identifying the event type. x-parser-schema-id: topic_description: type: string maxLength: 250 description: Human-readable description of the event. x-parser-schema-id: timestamp: type: integer description: Unix timestamp of the webhook delivery. example: 1777509495 x-parser-schema-id: version: type: string maxLength: 5 description: Payload contract version. example: '1' x-parser-schema-id: x-parser-schema-id: WebhookMetadata data: type: object required: - ancillary - event properties: ancillary: allOf: - type: object required: - notification_id - participant_unique_id1 description: >- Transaction correlation identifiers for Notify webhook events. Use these fields to match the event to a transaction in your system. properties: notification_id: type: string maxLength: 15 description: >- Ingo-assigned unique identifier for the staged notification. example: '10042781' x-parser-schema-id: session_id: type: string maxLength: 50 nullable: true description: Ingo-assigned session identifier, when applicable. x-parser-schema-id: participant_unique_id1: type: string maxLength: 100 description: >- Your primary correlation ID from the original Notify request. x-parser-schema-id: participant_unique_id2: type: string maxLength: 100 nullable: true description: Your optional secondary correlation ID. x-parser-schema-id: party_id: type: string maxLength: 36 nullable: true description: >- Ingo-assigned ID for the specific party this event relates to. Present on multi-party (Notify v4) events. x-parser-schema-id: x-parser-schema-id: NotifyCorrelation - type: object properties: tracer_token: type: string maxLength: 250 description: >- Ingo-assigned tracer identifier for the original request. Optional. x-parser-schema-id: x-parser-schema-id: SessionTracer x-parser-schema-id: event: allOf: - type: object required: - status - client_message description: >- Core event outcome fields present on every webhook event. Additional event-specific properties may be present — see the individual event documentation for the complete schema. properties: status: type: string maxLength: 10 description: Numeric status code for the event outcome. x-parser-schema-id: client_message: type: string maxLength: 250 description: Human-readable description of the event outcome. x-parser-schema-id: attempt_count: type: integer description: >- Current delivery attempt number. Present when the event type has a configurable attempt counter. example: 1 x-parser-schema-id: max_attempts: type: integer description: >- Maximum allowed attempts. Present when the event type has a configurable attempt counter. example: 3 x-parser-schema-id: x-parser-schema-id: WebhookEventBase - type: object required: - session_data description: Session initiation detail. properties: session_data: type: object description: >- Details of the browser request that started the party's session. The event fires once per session, so these fields describe the entry request only. Every field is always present; a field with no value is sent as an empty string. required: - timestamp_date - timestamp_time - cs_method - cs_uri_stem - cs_uri_query - cs_host - cs_referer - cs_user_agent - accept_language - client_ip - edge_request_id - ip_country - client_scheme - sec_ch_ua - sec_ch_ua_mobile - sec_ch_ua_platform - sec_fetch_site properties: timestamp_date: type: string maxLength: 20 description: UTC date of the entry request, `YYYY-MM-DD`. x-parser-schema-id: timestamp_time: type: string maxLength: 20 description: >- UTC time of the entry request, `HH:MM:SS`. May include fractional seconds. x-parser-schema-id: cs_method: type: string maxLength: 10 description: >- HTTP method of the entry request (for example `GET`). x-parser-schema-id: cs_uri_stem: type: string maxLength: 150 description: >- Path of the entry request, without the query string. x-parser-schema-id: cs_uri_query: type: string maxLength: 450 description: >- Query string of the entry request. Truncated at 450 characters. x-parser-schema-id: cs_host: type: string maxLength: 150 description: Host name the party's browser requested. x-parser-schema-id: cs_referer: type: string maxLength: 450 description: >- Referring page, from the browser's `Referer` header. Empty when the party opened the link directly. Truncated at 450 characters. x-parser-schema-id: cs_user_agent: type: string maxLength: 300 description: Browser `User-Agent` string. x-parser-schema-id: accept_language: type: string maxLength: 100 description: Browser `Accept-Language` header. x-parser-schema-id: client_ip: type: string maxLength: 45 description: >- IP address of the party's device as seen at Ingo's network edge, IPv4 or IPv6. x-parser-schema-id: edge_request_id: type: string maxLength: 100 description: >- Request identifier assigned at Ingo's network edge, including the edge location. Quote it to Ingo Support when asking about a specific session. x-parser-schema-id: ip_country: type: string maxLength: 3 description: >- Country of `client_ip`, ISO 3166-1 alpha-2. `XX` when the country can't be determined. x-parser-schema-id: client_scheme: type: string maxLength: 20 description: >- Original protocol of the entry request (`http` or `https`). x-parser-schema-id: sec_ch_ua: type: string maxLength: 150 description: >- Browser brand list with major versions, from the `Sec-CH-UA` client hint (for example `"Chromium";v="126", "Google Chrome";v="126"`). Chromium-based browsers only; empty otherwise. x-parser-schema-id: sec_ch_ua_mobile: type: string maxLength: 50 description: >- Mobile indicator, from the `Sec-CH-UA-Mobile` client hint (`?1` mobile, `?0` desktop). Chromium-based browsers only; empty otherwise. x-parser-schema-id: sec_ch_ua_platform: type: string maxLength: 50 description: >- Operating system family, from the `Sec-CH-UA-Platform` client hint (for example `"Windows"`, `"Android"`, `"macOS"`). Family only, no version. Chromium-based browsers only; empty otherwise. x-parser-schema-id: sec_fetch_site: type: string maxLength: 50 description: >- How the session started, from the `Sec-Fetch-Site` header: `none` = the party opened the link from an email, text message or bookmark; `cross-site` = the party arrived from another website; `same-origin` = navigation within the session site. Chromium-based browsers only; empty otherwise. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: EventSessionInitiated x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Party Session Initiated example: |- { "metadata": { "topic_description": "This event indicates that a multi-party session is initiated", "version": "1", "timestamp": 1762876169, "topic": "transaction.party.session.initiated", "id": "prod1-123456-abcd-1234-ab12-c123d456e789" }, "data": { "ancillary": { "party_id": "d3e65dc3-3b22-48ed-b54d-7244a60b7bca", "participant_unique_id2": "", "session_id": "00000000-0000-0000-0000-000000000001", "participant_unique_id1": "22222222-5555-3333333-4444444444", "notification_id": "1000001" }, "event": { "status": "100", "client_message": "Success", "session_data": { "timestamp_date": "2026-11-11", "timestamp_time": "18:29:29", "cs_method": "GET", "cs_uri_stem": "/session/start", "cs_uri_query": "src=email", "cs_host": "pay.example.com", "cs_referer": "https://mail.example.com/", "cs_user_agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36", "accept_language": "en-US,en;q=0.9", "client_ip": "203.0.113.77", "edge_request_id": "8c1f2e3d4b5a6978-ATL", "ip_country": "US", "client_scheme": "https", "sec_ch_ua": "\"Not/A)Brand\";v=\"8\", \"Chromium\";v=\"126\", \"Google Chrome\";v=\"126\"", "sec_ch_ua_mobile": "?0", "sec_ch_ua_platform": "\"Windows\"", "sec_fetch_site": "cross-site" } } } } bindings: [] extensions: - id: x-parser-unique-object-id value: TransactionPartySessionInitiatedMessage bindings: [] extensions: - id: x-parser-unique-object-id value: TransactionPartySessionInitiated sendOperations: - *ref_0 receiveOperations: [] sendMessages: - *ref_1 receiveMessages: [] extensions: - id: x-parser-unique-object-id value: TransactionPartySessionInitiated securitySchemes: [] ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.