This heatmap visualizes salary data across job titles and company sizes, using a blue sequential color scale where darker shades indicate higher salaries in USD. Hovering over any cell displays a tooltip with the exact salary value. Built with D3.js v7, it renders SVG rectangles positioned by scaleBand axes, with a linear color scale and an axis-based legend showing the salary range. The visualization loads data from a merged JSON dataset containing job and salary information.