Key Frequency Counter

Count and analyze key frequencies in your data

What This Tool Does

The Key Frequency Counter analyzes JSON arrays to determine how often each field (key) appears across all objects in your dataset. It calculates occurrence counts and percentages, helping you identify required fields, optional fields, and data completeness patterns. This analysis is crucial for understanding data structure consistency and identifying missing or sparse data.

Who It's For

Data analysts profiling datasets
API developers documenting responses
QA engineers validating data quality
Data engineers designing schemas

Typical Use Cases

Identifying required vs optional fields
Finding incomplete records
Data completeness analysis
API response profiling
Schema documentation

Input JSON Array

Frequency Results

Frequency analysis will appear here...

How It Works

Parse JSON Array

The tool validates your JSON input and extracts all objects from the array, preparing them for analysis.

Count Key Occurrences

Every object is scanned to identify which keys are present. The tool maintains a count of how many times each key appears across all objects.

Calculate Percentages

For each key, the tool calculates what percentage of objects contain that key, helping you understand data completeness.

Display Results

Results are sorted by frequency and displayed with visual indicators, making it easy to identify common and rare fields.

Examples

Example 1: Complete vs Incomplete Fields

Input:

[
  {"name": "John", "email": "[email protected]", "phone": "555-0001"},
  {"name": "Jane", "email": "[email protected]"},
  {"name": "Bob", "email": "[email protected]"},
  {"name": "Alice"}
]

Output:

name: 4/4 (100%)
email: 3/4 (75%)
phone: 1/4 (25%)

Common Errors

Not an array: Input must be a JSON array [...]
Empty array: Cannot analyze an empty array
Non-object items: Array should contain objects, not primitive values

When to Use This Tool

Use This Tool When:

You need to understand which fields are consistently present
You're documenting API response structures
You want to identify optional vs required fields
You're checking data completeness
You need to find sparse or rarely-used fields

Compared to Other Tools:

vs Data Type Analyzer: Use this for frequency; use analyzer for types
vs Consistency Checker: Use this for counts; use checker for validation
vs Schema Preview: Use this for statistics; use preview for structure

Limitations & Important Notes

File Size Limits

This tool processes data in your browser. JSON files larger than 5MB may cause performance issues. For very large datasets, consider sampling your data.

Data Integrity

While this tool counts key occurrences accurately, it does not validate whether the presence or absence of keys is correct for your business logic.

Nested Keys

This tool analyzes top-level keys only. Nested object keys are not counted separately. Consider flattening your data for deep analysis.

For Reference Only

This analysis is provided for reference and data exploration. Always validate your findings against your specific data requirements.

Privacy: All analysis happens locally in your browser. Your data is never sent to our servers.