Overview

Flash Update is a lightweight feed API that allows rapid updates to specific product fields without triggering enrichment or full reindexing. It is ideal for low-latency updates like availability toggles or simple price changes.

This avoids reprocessing the entire catalog and keeps updates fast.

Schema Upload Changes

To make a field eligible for Flash Update, explicitly mark it in your schema. When defining schema fields, add the parameter "flashUpdate": "true" to enable flash updates on that field.

Example Schema Defination

{
  "fieldName": "max_price",
  "multiValue": "false",
  "autoSuggest": "false",
  "dataType": "decimal",
  "flashUpdate": "true"
}

Flash Update Eligibility Rules

Ensure the following rules are followed for fast and safe updates via Flash Update.

Condition	Requirement
Data Type	Must be numeric (`decimal` or `int`)
Field Type	Must be single-value
Feature Field	Cannot be a feature field
Indexed Fields	Cannot be indexed (they won’t appear in search unless explicitly requested with `fl` parameter)

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Note

If flashUpdate is set to true for an invalid field type, schema upload will fail with one of these errors:

Flash updates not supported on non-numeric fields

Flash updates not supported on multi-valued fields

Flash Feed Upload API

These endpoints handle the actual flash updates.

Endpoint Versions:

v2.0: https://feed.unbxd.io/v2.0/sites/\{siteKey}/flash

v2.1:https://feed.unbxd.io/v2.1/sites/\{siteKey}/indexes/\{index}/flash

Using v2.1 when working with multiple indexes per site is advised.

Disallowed Scenarios

Misuse of Flash Update can create a heavy load and unnecessary reindexing. Do NOT use Flash Update to:

Update inventory counts (stock: 5, inventory: 23) as this causes high write volumes and index thrashing.
Updating fields is not enabled for Flash Update. For example, fields without flashUpdate: true
Modifying multi-valued or text-heavy fields such as product titles or brand names.

Valid Use Cases for Flash Update

Use Flash Update only when it provides a real benefit. The table below shows when to use Flash Update vs. Full/Delta Feed.

Scenario	Flash Update	Full/Delta Feed	Why
Minor Price Change like `max_price`, `selling_price`	Recommended	Not Needed	Flash updates handle quick, low-latency price changes efficiently.
Availability Flag Update like `inStock`, `store_availability`	Recommended	Not Needed	Ideal for toggling availability without reindexing the entire feed.
Inventory Count Update like `stock: 20`, `inventory: 23`	Not Allowed	Required	High write volume can cause index thrashing. Use delta feed instead.
Content Updates like `title`, `brand`, descriptions	Not Allowed	Required	Flash Update cannot handle text or multi-valued fields.
Enriched or Derived Fields like `badges`, dynamic fields	Not Allowed	Required	These fields require enrichment and full reindexing to reflect changes.
Bulk Catalog Changes (hundreds/thousands of products)	Not Ideal	Required	Full/Delta feeds are optimized for large-scale updates.

Sample API Call

curl -X POST https://feed.unbxd.io/v2.0/sites/{siteKey}/flash \
-H 'Authorization:{apiKey}' \
-H 'Content-Type: application/json' \
-d '[{"uniqueId":"96512","variants":[{"variantId":"93004","store_availability":1,"stores":[]}]}]'

Rate Limit

It prevents overloading the system.

Limit: 20 Flash Updates per minute
Per Call: Maximum 5 products per request
Throughput: 100 product flash updates per minute

FAQs

What is the Flash Update API and when should I use it?

Flash Update is a lightweight API that lets you update specific numeric product fields (like price or availability) without running a full feed reindex. Use it when you need low-latency updates for small, frequent changes.

Which fields can I update using Flash Update?

You can only update fields that:

Are numeric (int or decimal)
Are single-value fields
Are marked with "flashUpdate": "true" in your schema

Can I update text fields like product title or brand name?

No. Flash Update cannot modify text or multi-valued fields. Use a Full Feed or Delta Feed for such updates.