Nordic heraldry is the heraldic tradition of the Nordic countries ( Denmark, Sweden, Norway, Finland and Iceland). All those traditions are very alike with some minor differences. In addition to the nobility, gradually also commoners and even some farmers used arms. During 20th century interest in heraldry has again increased. Assuming arms was and is not regulated, and anyone can bear arms.
Nordic heraldry is a part of German heraldic tradition and is quite similar to it. Arms are often rather simple and stylized, with few charges and tinctures. Canting arms are common.
Standard heraldic tinctures are used. Purple is very rare and even restricted in its use, but in recent Swedish heraldry used more. Natural colours (proper) are mostly avoided in modern heraldry. Furs are rather rare.
House marks were historically a common charge in burgher arms, nowadays accepted if they follow heraldic rules and can be blazoned in heraldic terms.
Variations of line are common, especially in Finnish heraldry (which has created a few new variations, like fir-twigged and fir-tree-topped).
In Sweden and Finland, the open helmet is used only by the nobility and burgher arms use a tilting helmet, while in Denmark and Norway both nobles and commoners may use an open helmet. The number of helmets above the shield indicates the noble rank. Sometimes the use of a torse is seen as optional, especially if the crest transitions seamlessly into the mantling. Bull horns, eagle wings and flags are common in crests, and the crest quite often repeats the charge or colours/pattern of the shield.
All those traditions do not have a fixed system of cadency, all descendent of the armiger inherit his arms equally. Though historical coats of arms are still inherited agnatically, it is often no longer true for modern coats of arms. Differencing the arms by changing the shield elements and/or the crest is sometimes done.
Personal heraldry is not regulated in Nordic counties and there is no heraldic authority for it. Instead, there is a plenitude of heraldic associations, assisting with the creation and assumption of new arms, as well as the documentation of arms via periodically publishing roll of arms.