---
title: Calendar Heatmap Chart
slug: generate-calendar-heatmap-chart
url: https://apyverse.com/apyhub/service/generate-calendar-heatmap-chart
provider: ApyHub
categories: [Image Processing, Smart Generation]
tags: [calendar-heatmap, chart-generation, data-visualization, image-generation, date-metrics]
auth: api_key
---

# Calendar Heatmap Chart

Generate a calendar heatmap from title and date/value data, with optional hex color controls. Return either binary image data or a pre-signed PNG link.

## Endpoints

| Method | Path | Description | Atoms |
| --- | --- | --- | --- |
| POST | `/download` | What it does Generates a calendar heatmap chart image from a chart title and an array of dated nume… | 10 |
| POST | `/link` | What it does Generates a calendar heatmap chart link from a chart title, a non-empty series of date… | 10 |

## About

## What it does
Calendar Heatmap Chart generates a calendar-style heatmap image or a pre-signed download link from dated numeric data. Send a title and an array of `{date, value}` objects, and get back a chart you can embed in dashboards, reports, or internal tools.

Use the `/download` endpoint when you want the chart image itself. It accepts a `body` object with a required `title`, a required `data` array, and an optional `options` object for custom colors. Each data point needs a `date` in `YYYY-MM-DD` format and a numeric `value`. The response is binary image data. Use `/link` with the same request body when you want a JSON response containing a `data` field with a pre-signed URL to the generated PNG.

Calendar Heatmap Chart is a good fit for showing daily activity, commits, sign-ins, completed tasks, or any other metric that changes over time. It makes sparse or seasonality-heavy data easy to scan at a glance, especially when you need a compact year view instead of a line chart.

If you need a chart image generated from date/value records and want simple color control through hex values, this API keeps the input shape small and the output straightforward.

## Usage

Authenticate with an ApyHub API key in the `apy-token` header.
Full docs and a live playground: https://apyverse.com/apyhub/service/generate-calendar-heatmap-chart