tl;dr: Modules go into the colored slots of weapons and abilities and raise one or two of their stats. There are six basic modules in three colors, twelve hybrids made out of two basic ones, and nine ranks (Mk.1 to Mk.9). Modules have no level requirement, and the same module works in a weapon and in an ability.

Basic Modules

Basic modules drop from enemies and are part of mission rewards. What a module does depends on where you put it:

	Module	Color	In a Weapon	In an Ability
	Rate Enhancer	Red	Rate of fire, charge-up speed	Recharge rate, or the charge rate of an ultimate ability
	Force Enhancer	Red	Damage (it adds power rating)	Damage, healing and shield health
	Capacity Booster	Yellow	Magazine size	Duration
	Precision Booster	Yellow	Accuracy and handling	Potency
	Range Amplifier	Blue	Range	Range
	Radial Amplifier	Blue	Area of effect	Area of effect

Hybrid Modules

A Tinker can combine two basic modules of different colors and the same rank into a hybrid of that rank. The hybrid has both sets of stats, but only about 70% of each. That's still 40% more in total than a basic module, at the price of being less focused. Note that hybrids don't drop, they always have to be made.

	Hybrid	Color	Made from
	Enduro Pod	Orange	Rate Enhancer + Capacity Booster
	Quicksilver Pod	Orange	Rate Enhancer + Precision Booster
	Hailstorm Pod	Orange	Force Enhancer + Capacity Booster
	Roundhouse Pod	Orange	Force Enhancer + Precision Booster
	Flood Chip	Green	Capacity Booster + Range Amplifier
	Deluge Chip	Green	Capacity Booster + Radial Amplifier
	Marksman Chip	Green	Precision Booster + Range Amplifier
	Firestorm Chip	Green	Precision Booster + Radial Amplifier
	Pulsating Dynamo	Purple	Rate Enhancer + Range Amplifier
	Behemoth Dynamo	Purple	Rate Enhancer + Radial Amplifier
	Impact Dynamo	Purple	Force Enhancer + Range Amplifier
	Collateral Dynamo	Purple	Force Enhancer + Radial Amplifier

Red and yellow make orange, yellow and blue make green, red and blue make purple. The two modules of the same color can't be combined with each other.

Ranks

The rank decides how much a module adds and also its rarity. The values are rating points on the stat, not percent.

To raise the rank, a Tinker combines the module with two other modules of the same rank and color. The other two don't have to be of the same type, any two red Mk.3 modules will turn your Rate Enhancer Mk.3 into a Mk.4. As such every module you find is progress, even the ones you'd never slot. The costs are listed in the tinkering guide.

Slots

Weapons and abilities have colored module slots, and a module only fits a slot of its color. How many slots an item has and which colors they are depends on the item. Removing a module from its slot costs Credits, though a lot less than it did before update 1.6.

Prototype Modules

A few modules don't follow these rules. Prototype modules like Apotheosis are rewards of specific missions and operations, have a unique effect, fit either a weapon or an ability and have no rank, so they can't be combined. The Deployment modules, which raise the number of deployables you can have out, are prototypes as well and drop in operations. Some of the older unique modules, Judgment for example, were turned into gadgets with update 1.6.