Choose the relationship between hues
Complementary uses opposite hues; analogous uses nearby hues; triadic spreads hues evenly. The first swatch keeps your exact HEX seed. Lock a swatch before generating again to keep it. To adjust the seed in RGB, HSL or HSV first, use the color picker.
A worked example
A seed of #0B7285 stays #0B7285. Triadic companion hues are separated by 120 degrees, while shade swatches change lightness.
Before you use the result
A harmony is a starting point, not a readability guarantee. Check text contrast in the final design. Randomize chooses a new seed and keeps any locked swatches.