Aggregations

Aggregations summarise enriched customer transactions into structured data that supports affordability analysis, cashflow review, and financial behaviour assessment.

Prefer using the web app?

When you submit transaction data in the Walker Street Data sandbox application, and your API key has the transactions:aggregate scope, aggregations are automatically returned. This guide details the equivalent workflow using the API.

Prerequisites

• Valid customerId — see Create a Customer
• Enriched transactions available for that customer — see Extract Bank Statement Transactions or Classify Transactions
• API scope: transactions:aggregate

Endpoints

Standard response

GET https://api.walkerstdata.com.au/v1/customer/{customerId}/aggregate

File download

GET https://api.walkerstdata.com.au/v1/customer/{customerId}/aggregate/download

Request Parameters

Parameter	Location	Required	Description
customerId	path	Yes	Unique customer identifier
jobId	query	No	Filter aggregations to a specific enrichment job
type	query	Yes (download only)	File format: json or csv

Example Request

cURL

curl -X GET "https://api.walkerstdata.com.au/v1/customer/{customerId}/aggregate" \
  -H "x-api-key: YOUR_API_KEY"

JavaScript

const customerId = 'your-customer-id';

const response = await fetch(
  `https://api.walkerstdata.com.au/v1/customer/${customerId}/aggregate`,
  {
    method: 'GET',
    headers: { 'x-api-key': 'YOUR_API_KEY' },
  }
);

const result = await response.json();
console.log(result.data.tables);

Filtering by Job

If you enriched transactions via a specific job, pass jobId to scope the aggregation to that submission:

cURL

curl -X GET "https://api.walkerstdata.com.au/v1/customer/{customerId}/aggregate?jobId={jobId}" \
  -H "x-api-key: YOUR_API_KEY"

JavaScript

const customerId = 'your-customer-id';
const jobId = 'your-job-id';

const response = await fetch(
  `https://api.walkerstdata.com.au/v1/customer/${customerId}/aggregate?jobId=${jobId}`,
  {
    method: 'GET',
    headers: { 'x-api-key': 'YOUR_API_KEY' },
  }
);

const result = await response.json();
console.log(result.data.tables);

Download as File

cURL

curl -X GET "https://api.walkerstdata.com.au/v1/customer/{customerId}/aggregate/download?type=csv" \
  -H "x-api-key: YOUR_API_KEY"

JavaScript

const customerId = 'your-customer-id';

const response = await fetch(
  `https://api.walkerstdata.com.au/v1/customer/${customerId}/aggregate/download?type=json`,
  {
    method: 'GET',
    headers: { 'x-api-key': 'YOUR_API_KEY' },
  }
);

const result = await response.json();
console.log(result.data);

Response Fields

The response returns a tables array of aggregation nodes. Each node contains:

Field	Description
id	Unique identifier for the aggregation node
name	Human-readable label for the aggregation category, when available
hierarchy	Structural role of the node in the aggregation output, such as table, subtable, row, or total
type	Data shape of the node's values field, such as objectArray, timeseries, or keyValue
values	Aggregated values for the node. The structure depends on the node type

Interpreting Results for Credit

• Use hierarchy to understand where a node sits in the report structure: top-level sections, nested subtables, individual rows, and totals
• Use type to determine how to parse values — for example as an array of child nodes, a time series object, or a key-value object
• Compare income and expense node values across the assessed period to inform serviceability calculations
• Combine Aggregations with Completeness — low data coverage can distort aggregated totals and reduce confidence in the figures

Common Errors

Status	Cause
400	Transactions list is empty or jobId is invalid
403	Missing API scope transactions:aggregate

Next Steps

• Completeness — Validate data coverage before relying on aggregated totals
• Risk Score — Add a risk signal to complement affordability analysis
• API Reference — Full endpoint schema and parameter details