---
title: Generate HeatMap Chart API
slug: generate-simple-heatmap-chart
url: https://apyhub.com/apyhub/service/generate-simple-heatmap-chart
provider: ApyHub
categories: [Image Processing, Smart Generation]
tags: [calendar-heatmap, data-visualization, chart-generation, image-generation, time-series]
auth: api_key
---

# Generate HeatMap Chart API

Generate calendar heatmap charts from dated numeric data. Returns a chart image file or a pre-signed image URL for dashboards and reports.

## Endpoints

| Method | Path | Description | Atoms |
| --- | --- | --- | --- |
| POST | `/download` | What it does Generates a calendar heatmap chart image from the supplied data and title, then return… | 60 |
| POST | `/link` | What it does Generates a calendar heatmap chart link from the provided title, dated data points, an… | 60 |

## About

## What it does
Heatmap Chart Generator turns dated numeric data into a calendar heatmap chart and returns either an image file or a pre-signed image URL.

Send Heatmap Chart Generator a `title` and a `data` array. Each data point must include a `date` in `YYYY-MM-DD` format and a numeric `value`. You can also pass an `options` object to tune the chart colors with `color_low`, `color_med`, `color_high`, `color_empty`, and `color_med_low`, each as a 6-character hex value without the `#`.

Use it when you need to visualise activity over time: daily sign-ins, commits, orders, support tickets, or any other date-based metric that is easier to read as a calendar grid than as a table. The `/download` endpoint generates the chart image, while `/link` returns a `data` field containing a URI to the generated chart image.

Keep the input small and explicit: a title, at least one dated value, and optional color settings. The response stays focused on the generated chart output, so it fits cleanly into reporting flows, dashboards, and internal analytics tools.

## Usage

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