Noisebud has announced the release of Purr-Fect, a plugin that will add real-time gain compensation to any plugin or hardware. It does that by using a sidechain input with the dry signal to constantly compare and adjust the gain for the processed signal.
Here's what they say:
If you used RMS-based plugins like MeterPlugs Perception or LetiMix Gain Match you'll know the power of gain compensation. Purr-Fect does the same but instead of using the slower RMS method, it adapts the level of the dry signal to the processed signal instantly which makes it suitable for detail work rather than a zoomed-out greater picture kind of work. For example, you'll be able to perform drastic EQ changes without affecting compression later in the chain.
To download it you need to sign up as a Noisebud Patreon (from $5 per month): patreon.com/noisebud