diff --git a/README.md b/README.md
index cdc501e..16fd008 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,8 @@ Visualizations are written in JavaScript and use HTML Canvas (2d or 3d) to rende
 
 ## Writing Visualizations
 
-See the [developer guide](./docs/dev-guide.md).
+- [SKQW developer guide - intro](./docs/dev-guide.md)
+- [SKQW API Docs](./docs/api.md)
 
 ## Building From Source (Windows)
 
diff --git a/docs/api.md b/docs/api.md
new file mode 100644
index 0000000..dd82ec3
--- /dev/null
+++ b/docs/api.md
@@ -0,0 +1,113 @@
+# SKQW APIs
+
+This is a description of the APIs for authoring visualizations in SKQW.
+For a general overview, see the [dev guide](./dev-guide.md).
+
+## `skqw` object
+The `skqw` object is passed as an argument to most of the lifecycle 
+functions (see Visualization interface below). 
+
+```TypeScript
+interface ISkqw {
+    createCanvas: (domElement?: HTMLCanvasElement) => HTMLCanvasElement;
+    dimensions: {
+        width: number;
+        height: number;
+    };
+    sample: {
+        ts: number[];
+        ft: number[];
+    }
+}
+```
+
+#### `skqw.createCanvas()`
+
+If called with no arguments, it will create a new `<canvas>` element
+and return it.
+
+Alternatively you may create the canvas element yourself, and pass it 
+as an argument to `createCanvas()`. This is useful, for example, when
+using a library such as Three.js, which will provide you with a canvas
+element itself, which can then be handed over to SKQW.
+
+#### `skqw.dimensions.width`
+
+The width of the canvas in pixels.
+
+#### `skqw.dimensions.height`
+
+The height of the canvas in pixels.
+
+#### `skqw.sample.ts`
+
+An array of numbers representing the time series of the audio
+sample (time domain). Also known as a waveform.
+
+#### `skqw.sample.ft`
+
+An array of numbers representing the fast fourier transform of the 
+signal (frequency domain). Also known as a frequency spectrum.
+
+## Visualization Interfaces
+
+```TypeScript
+
+interface IVisualization {
+    name: string;
+    init: (skqw: ISkqw) => void;
+    tick: (skqw: ISkqw, timestamp: number) => void;
+    resize?: (skqw: ISkqw) => void;
+    destroy?: (skqw: ISkqw) => void;
+    paramChange?: (change: IParamUpdate) => void;
+    params?: { [name: string]: IParameter }
+}
+
+interface IParameter {
+    value: number | boolean;
+    type: 'range' | 'boolean';
+    label: string;
+    min?: number;
+    max?: number;
+    step?: number;
+}
+
+interface IParamUpdate {
+    paramKey: string;
+    newValue: number | boolean;
+}
+```
+
+#### `visualization.name`
+
+The name which will be displayed in the app UI.
+
+#### `visualization.init(skqw)`
+
+Called once when the visualization is selected in the UI.
+
+#### `visualization.tick(skqw, timestamp)`
+
+Called for each frame of the visualization animation, roughly 60 times
+per second. The `timestamp` is a [DOMHighResTimeStamp](https://developer.mozilla.org/en-US/docs/Web/API/DOMHighResTimeStamp)
+provided by the [requestAnimationFrame()](https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame)
+method which is used internally.
+
+#### `visualization.resize(skqw)`
+
+Called whenever the app window is resized.
+
+#### `visualization.destroy(skqw)`
+
+Called just before unloading the visualization, as when a different 
+visualization is selected in the UI.
+
+#### `visualization.paramChange(change)`
+
+Called whenever the user changes a param in the UI.
+
+#### `visualization.params`
+
+An object describing the user-configurable parameters which may be
+changed at run time to alter the way the visualization renders.
+
diff --git a/docs/dev-guide.md b/docs/dev-guide.md
index 33c4ce0..cdb45c6 100644
--- a/docs/dev-guide.md
+++ b/docs/dev-guide.md
@@ -6,6 +6,21 @@ recent versions of Node and Chrome, you are free to use (most) ES2015
 language features. One notable exception is that module imports and 
 exports must be in the [Node commonjs](https://nodejs.org/docs/latest/api/modules.html) (`module.exports` and `require()`) format.
 
+## File Location & Naming
+
+A visualization main file must be located in a subdirectory of the 
+"library path" (as set in the UI), and must be named "index.js":
+
+```
+// "visualizations" is set as the library path in the app.
+
+- visualizations/
+    |
+    |- myVis/
+    |   |- index.js
+    |
+```
+
 ## Basic Example
 
 Here is a bare-bones visualization:
@@ -92,9 +107,9 @@ red bar whose height is proportional to the value of that frequency.
 
 #### `module.exports` 
 Finally, we export the required information as a [Node commonjs](https://nodejs.org/docs/latest/api/modules.html) module.
-There are more functions and properties which SKQW can read, which lets
-us write richer visualizations, but the three shown are the bare minimum
-required for things to work.
+There are more functions and properties which SKQW can read (see the 
+[API docs](./api.md)), which lets us write richer visualizations, but the 
+three shown are the bare minimum required for things to work.
 
 ## Parameters
 
@@ -170,10 +185,10 @@ SKQW knows about them.
 ## Next Steps
 
 Now you should know enough to start playing around with SKQW 
-visualizations and creating some cool visuals.
+visualizations and creating some cool visuals!
 
 There are a few more parts of the API not covered above. For a full
-rundown of all APIs, see the API Reference.
+rundown of all APIs, see the [API Reference](./api.md).
 
-Another great way to learn is to take a look at the source code of the
-standard library of visualizations. 
\ No newline at end of file
+Another great way to learn is to take a look at the [source code of the
+standard library of visualizations](../visualizations). 
diff --git a/src/common/models.ts b/src/common/models.ts
index 6c69744..4524d5d 100644
--- a/src/common/models.ts
+++ b/src/common/models.ts
@@ -8,6 +8,18 @@ export interface ISample {
     ts: number[];
 }
 
+export interface ISkqw {
+    createCanvas: (domElement?: HTMLCanvasElement) => HTMLCanvasElement;
+    dimensions: {
+        width: number;
+        height: number;
+    };
+    sample: {
+        ts: number[];
+        ft: number[];
+    }
+}
+
 export interface IParameter {
     value: number | boolean;
     type: 'range' | 'boolean';
@@ -22,11 +34,11 @@ export interface IParameter {
  */
 export interface IVisualization {
     name: string;
-    init: (skqw: any) => void;
-    tick: (skqw: any, timestamp: number) => void;
-    resize?: (skqw: any) => void;
-    destroy?: (skqw: any) => void;
-    paramChange?: (change: { [paramKey: string]: any }) => void;
+    init: (skqw: ISkqw) => void;
+    tick: (skqw: ISkqw, timestamp: number) => void;
+    resize?: (skqw: ISkqw) => void;
+    destroy?: (skqw: ISkqw) => void;
+    paramChange?: (change: IParamUpdate) => void;
     params?: { [name: string]: IParameter }
 }
 
diff --git a/src/render/components/visualizer/visualizer.component.ts b/src/render/components/visualizer/visualizer.component.ts
index 366eaf5..ec50af0 100644
--- a/src/render/components/visualizer/visualizer.component.ts
+++ b/src/render/components/visualizer/visualizer.component.ts
@@ -1,5 +1,5 @@
 import {Component, ElementRef, Input, SimpleChange} from '@angular/core';
-import {IVisualization, ISample, IParamUpdate} from '../../../common/models';
+import {IVisualization, ISample, IParamUpdate, ISkqw} from '../../../common/models';
 import {defaultVis} from './defaultVisualization';
 
 export interface IDimensions {
@@ -23,7 +23,7 @@ export class Visualizer {
 
     @Input() sample: ISample;
     @Input() visualization: IVisualization;
-    private skqw;
+    private skqw: ISkqw;
     private canvases: HTMLCanvasElement[] = [];
     private dimensions: IDimensions = { width: 0, height: 0 };
     private resizeTimer: any;