Distributor Knowledge Base

Delta vs. Overlay

Modified on: 2025-08-06 17:09

TABLE OF CONTENTS

Introduction
How to identify the Push Mode
How it works

Introduction

Regarding the GO Distributor Push Model, there are two modes: Delta and Overlay.

Delta - It's an incremental update for the changed products and it supports up to 15 products per request. If the number of changed products exceeds 15, multiple push requests will be sent.
Overlay - All products undergo a full update whenever any product has an ARI change.

How to identify the Push Mode

You can identify the push mode through the MessageType field in the request of AvailabilityPeer - ARI Push API. Below is an example for Delta mode, please notice that If the field is omitted in the request it means the message type is Overlay.

{
  "header": {
    "supplierId": "HILTON",
    "distributorId": "GTA",
    "version": "v4",
    "token": "18393849028490234"
  },
  "messageType": "Delta",
  "hotelId": "GATHI",
  "dateRange": {
    "startDate": "2018-01-01",
    "endDate": "2018-01-04"
  },
  "currency": "USD",
  "dailyAris": [
    {
      "roomId": "K1",
      "rateId": "BARB",
      "mealPlans": [
        "BB",
        "BB",
        "BB",
        "BB"
      ],
      "inventories": [
        9,
        0,
        9,
        9
      ],
      "rates": {
        "type": "OccupancyRate",
        "rates": [
          {
            "adultCount": 2,
            "childCount": 1,
            "amountBeforeTax": [
              502.19,
              502.19,
              502.19,
              502.19
            ],
            "amountAfterTax": [
              623.23,
              623.23,
              623.23,
              623.23
            ]
          }
        ]
      },
      "availStatuses": {
        "close": [
          false,
          false,
          false,
          false
        ],
        "minStayArrival": [
          0,
          2,
          0,
          0
        ],
        "maxStayArrival": [
          0,
          2,
          0,
          0
        ],
        "minStayThrough": [
          0,
          2,
          0,
          0
        ],
        "maxStayThrough": [
          0,
          2,
          0,
          0
        ],
        "minAdvanceDay": [
          0,
          2,
          0,
          0
        ],
        "maxAdvanceDay": [
          365,
          365,
          365,
          365
        ],
        "cta": [
          false,
          false,
          false,
          true
        ],
        "ctd": [
          false,
          false,
          false,
          true
        ],
        "fplos": [
          "1111111",
          "1001111",
          "1000001",
          "0000000"
        ]
      }
    }
  ]
}

How it works

Refer to the sample below for clarification: There are a total of 4 products available for hotel GOH101, which are combined by roomId and rateId.

Hotel	RoomId	RateId	Rate	Inventory
GOH101	T2	BAR
GOH101	T2	PROMO	Changed
GOH101	FM4	BAR		Changed
GOH101	FM4	PROMO

Overlay mode will push a full update for ALL products in one request for the hotel.

Hotel	RoomId	RateId	Availability	Rate	Inventory
GOH101	T2	BAR	√	√	√
GOH101	T2	PROMO	√	√	√
GOH101	FM4	BAR	√	√	√
GOH101	FM4	PROMO	√	√	√

Delta mode only updates ARI for the changed products.

Hotel	RoomId	RateId	Availability	Rate	Inventory
GOH101	T2	PROMO	√	√	√
GOH101	FM4	BAR	√	√	√

Note:
The default PUSH Mode for new distributor is Delta. If needed you can change it to Overlay on GO Console.

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English

Delta vs. Overlay

Introduction

How to identify the Push Mode

How it works