Designing Architect flows that consume paginated REST APIs with loop counters

How-To-Articles
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Designing Architect flows that consume paginated REST APIs with loop counters

Executive Summary & Architectural Context

Modern CCaaS integrations rarely involve a single, flat JSON response. Whether you are fetching a list of open cases from Salesforce, checking a customer’s last 10 transactions in a core banking system, or retrieving agent schedules via the WFM API, you will inevitably encounter Pagination.

Architect is a functional, state-based engine, not a procedural programming environment. Handling nextPageToken or pageOffset requires a sophisticated loop structure that prevents infinite recursion, respects platform rate limits, and manages memory effectively. This masterclass provides the definitive blueprint for building robust, multi-page API consumption logic within a call flow.

Prerequisites, Roles & Licensing

  • Licensing Tier: Genesys Cloud CX 1, 2, or 3.
  • Granular Permissions:
    • Architect > Data Action > Execute
    • Integrations > Action > View
  • OAuth Scopes: Dependent on the target API (e.g., integration, crm).
  • Dependencies: A REST API that supports standard pagination (Cursor-based or Offset-based).

The Implementation Deep-Dive

1. The Data Action: Preparing for Iteration

To consume a paginated API, your Data Action must be flexible enough to accept a pageNumber or pageToken as an input variable.

Data Action Input Schema:

{
  "customerId": "string",
  "pageSize": "integer",
  "pageNumber": "integer"
}

The Response Mapping:
Crucially, you must map the pagination metadata from the response.

{
  "totalResults": "$.total",
  "nextPage": "$.metadata.next_page_link",
  "items": "$.entities"
}

2. The Architect Loop Structure

In Architect, you cannot use a for or while loop in the traditional sense. You must use a Task with a Decision block that routes back to the start of the lookup.

The State Variables:
Initialize these at the start of your Task using an Update Data action:

  • Flow.CurrentPage: 1
  • Flow.MaxPages: 5 (Always set a hard limit to prevent infinite loops)
  • Flow.TargetFound: false
  • Flow.ItemsProcessed: 0

The Iteration Logic:

  1. Call Data Action: Pass Flow.CurrentPage as the input.
  2. Success Path:
    • Use a Loop action to iterate through the current page’s items array.
    • Inside the loop, check if the specific record (e.g., a high-priority ticket) is found.
    • If found, set Flow.TargetFound = true and use a Change State or Exit Loop action.
  3. End of Page Path:
    • If Flow.TargetFound is still false, check if more pages exist (Flow.CurrentPage < Flow.MaxPages AND DataAction.nextPage != NOT_SET).
    • If yes: Increment Flow.CurrentPage and route the flow back to the Call Data Action step.
    • If no: Exit the loop and proceed to the “Not Found” logic.

[!WARNING]
The Trap: Failing to implement a Flow.MaxPages guard. If an upstream API has a bug and always returns a nextPageToken, Architect will continue looping until the interaction hits the platform’s execution limit (typically 60 seconds of CPU time), causing the call to drop or error out for the customer.

3. Managing Execution Time & Rate Limits

Every Data Action call in the loop consumes time and API quota.

Architectural Reasoning:
If you need to search through 100+ items, do not set pageSize to 1. Set it to the maximum the API allows (usually 25 or 50). This minimizes the number of “Round Trips” between Genesys Cloud and the external system, reducing the latency the caller hears as silence.

[!TIP]
Pro Tip: Play a short, non-intrusive “Please wait while I retrieve your records” prompt before entering the loop. If the loop takes more than 2-3 iterations, consider playing a periodic “Still looking…” comfort prompt to prevent the caller from thinking the line is dead.

Validation, Edge Cases & Troubleshooting

Edge Case 1: The “Moving Target” Problem

The failure condition: Between Page 1 and Page 2, a new record is added to the external system, causing the items to shift and the same record to appear on both pages (or be skipped entirely).
The root cause: Use of offset based pagination on a highly volatile dataset.
The solution: Use Cursor-based pagination (e.g., nextPageToken) if the target API supports it. Cursors are typically snapshots and are resistant to mid-stream data changes.

Edge Case 2: 429 Too Many Requests

The failure condition: The loop triggers 5 API calls in 1 second, hitting the external system’s per-user rate limit.
The root cause: Architect executes logic faster than many legacy CRM APIs can handle.
The solution: Add a Wait action of 500ms inside the loop before re-calling the Data Action. This “Cooldown” period ensures compliance with external rate limits.

Official References