diff --git a/README.md b/README.md
index bba159f..a55ca7c 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,8 @@ can peek at the opinions baked into this [here](./DESIGN_DECISIONS.md).
 
 Documentation can be found [here](./docs/INDEX.md) and welcomes contributions!
 
+API documentation can also be found [here](./docs/API.md).
+
 ## Development
 
 This uses [Corepack](https://github.com/nodejs/corepack), which comes bundled with `node>=16` to manage which Yarn version to use.
diff --git a/docs/API.md b/docs/API.md
new file mode 100644
index 0000000..76bc7b6
--- /dev/null
+++ b/docs/API.md
@@ -0,0 +1,274 @@
+# API documentation
+---
+## ./src/worker.ts
+
+---
+
+Worker runtime
+
+The worker executes the tests by called `node` on them. Since each test
+is an self-contained executable file, the worker can run each of them,
+collect output and relay it back to the runner process via IPC.
+
+Each worker process is responsible for as many test files as the runner
+decides to assign it and files assigned to the worker are only
+touched by the worker assigned to them.
+
+
+---
+### function / work
+```ts
+async function work()
+```
+
+
+Entrypoint for the worker.
+
+Retrieves paths assigned to the worker from the arguments passed when
+calling the worker runtime and spawns processes to run the test file
+pointed at by each of the paths.
+
+This will spawn one process per file and each process will communicate back
+to the worker's parent process as it finishes.
+
+If the `TS` flag is passed, the worker runs the test file using ts-node
+for Typescript compatibility.
+
+
+## ./src/testComponents/matchers.ts
+
+---
+
+Built-in matchers
+
+All the matchers defined and exported as part of the default export
+of this file are available to each `expect` statement made in tests.
+
+A matcher's inverse is defined by its behaviour when the `negated` flag
+that is passed to it is truthy.
+
+
+---
+### function / toEqual
+```ts
+function toEqual(value: unknown, other: unknown, negated: boolean = false): MatcherReport
+```
+
+
+`toEqual` asserts whether `value` and `other` are strictly equal.
+
+Once registered, it can be used as
+
+```ts
+expect(value).toEqual(other)
+```
+
+and in negated form
+
+```ts
+expect(value).not.toEqual(other)
+```
+
+
+---
+### function / toNotEqual
+```ts
+function toNotEqual(value: unknown, other: unknown, negated: boolean = false): MatcherReport
+```
+
+
+`toNotEqual` is the inverse of `toEqual` and behaves the same way as
+`expect(...).not.toEqual(...)`. Negating it behaves like `toEqual`.
+
+
+---
+### function / toBe
+```ts
+function toBe(value: unknown, other: unknown, negated: boolean = false): MatcherReport
+```
+
+
+Asserts whether value and other are the same entity.
+
+
+---
+### function / toNotBe
+```ts
+function toNotBe(value: unknown, other: unknown, negated: boolean = false): MatcherReport
+```
+
+
+Inverse of toBe.
+
+
+---
+### function / toThrow
+```ts
+function toThrow(func: () => unknown, negated: boolean = false): MatcherReport
+```
+
+
+Asserts whether the provided function throws the provided error.
+
+
+---
+### function / toNotThrow
+```ts
+function toNotThrow(func: () => unknown, negated: boolean = false): MatcherReport
+```
+
+
+Inverse of toThrow.
+
+
+---
+### function / toHaveLength
+```ts
+function toHaveLength(value: unknown, length: unknown, negated: boolean = false): MatcherReport
+```
+
+
+Validates that the `value` has a length of `length`. The value provided to `value` should
+have a defined length (i.e. it can be a string or some sort of iterable).
+
+
+## ./src/testComponents/test.ts
+
+---
+### function / test
+```ts
+function test(label: TestCaseLabel, testCase: TestCaseFunction): void
+```
+
+
+`test` defines a single test case.
+
+```
+test('My test', () => {
+// Assert things.
+})
+```
+
+
+---
+
+`it` is an alias of `test`.
+
+
+## ./src/testComponents/expect.ts
+
+---
+
+The `expect` function returned is the main access point
+to create Expect objects. On import, all the built-in matchers
+are registered, but more can be registered ad-hoc via `addMatcher`.
+
+
+## ./src/testComponents/describe.ts
+
+---
+### function / describe
+```ts
+function describe(label: TestCaseLabel, testGroup: TestCaseGroup)
+```
+
+
+`describe` facilitates grouping tests together.
+
+```
+describe('My test group', () => {
+test('My first test', ...)
+
+test('My second test', ...)
+})
+```
+
+
+## ./src/runner.ts
+
+---
+### function / collectTests
+```ts
+async function collectTests(roots: Array<string>): Promise<Array<string>>
+```
+
+
+Collects test files recursively starting from the provided root
+path.
+
+
+---
+### function / assignTestsToWorkers
+```ts
+async function assignTestsToWorkers(
+	context: Context,
+	collectedPaths: Array<string>,
+	workerCount: number = 1,
+): Promise<{ [key: number]: WorkerReport }>
+```
+
+
+Splits the list of collected test files into `workerCount` batches and starts
+worker processes.
+
+
+## ./src/logging.ts
+
+---
+### class / Logger
+
+Standard logger for anything that needs to print messages to the user.
+
+This supports the same general functionality as the `Console` logger,
+including `group` and various levels of logging.
+
+
+## ./src/utils.ts
+
+---
+### function / boldText
+```ts
+export function boldText(text: string | number): string
+```
+
+
+Terminal text style
+
+
+---
+### function / assertTsNodeInstall
+```ts
+export function assertTsNodeInstall()
+```
+
+
+To support typescript source directly, womm uses ts-node in
+workers to execute test files.
+
+If ts-node is not installed, this throws.
+
+
+---
+### function / getContext
+```ts
+export function getContext(runnerPath: string, ts: boolean = false): Context
+```
+
+
+Generates a context object that contains general information
+about the test runner. The parameter here should always be
+`process.argv[1]`, which will allow all the other paths
+to be set properly.
+
+
+---
+### function / splitIntoBatches
+```ts
+export function splitIntoBatches<T>(data: Array<T>, desiredBatchCount: number = 1): Array<Array<T>>
+```
+
+
+Divides the given list into `desiredBatchCount` batches, returning
+an array of arrays which add up to the given list.
+
+
diff --git a/docs/README.md b/docs/README.md
index 02fc2f1..b668d27 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -2,3 +2,4 @@
 
 - [Writing tests](./WRITING_TESTS.md)
 - [Extending with custom matchers](./CUSTOM_MATCHERS.md)
+- [API documentation](./API.md)
diff --git a/docs/generate.ts b/docs/generate.ts
new file mode 100644
index 0000000..72b036e
--- /dev/null
+++ b/docs/generate.ts
@@ -0,0 +1,111 @@
+import * as ts from 'typescript'
+import { promises as fs } from 'fs'
+import childProcess from 'child_process'
+import path from 'path'
+
+interface ExtractedNode {
+	name?: string
+	snippet?: string
+	comment?: string
+	type?: string
+}
+
+interface APIDocumentationNode {
+	sourcePath: string
+	targetPath: string
+	content: string
+}
+
+const API_DOC_PATH = './docs/API.md'
+
+function formatFunctionDeclaration(node: ts.FunctionDeclaration, fullText: string): string {
+	const declarationStart = node.getStart()
+	const declarationEnd = node.body?.pos ?? declarationStart
+	return fullText.slice(declarationStart, declarationEnd)
+}
+
+/*
+ *  Documentation extraction
+ *
+ *  This extracts block comments and declared entities from source files
+ *  and reformats it so publishable documentation can be generated from it.
+ */
+async function generateDocumentation() {
+	const rootPaths = process.argv.slice(2)
+	const output = childProcess.execSync(`find ${rootPaths.join(' ')} -name *.ts`, { encoding: 'utf8' })
+
+	const files: Array<APIDocumentationNode> = []
+
+	const sourcePaths = output.split('\n').filter((filePath) => Boolean(filePath))
+
+	for await (const sourcePath of sourcePaths) {
+		const rawContent = await fs.readFile(sourcePath, { encoding: 'utf8' })
+
+		const source = ts.createSourceFile(sourcePath, rawContent, ts.ScriptTarget.ES2015, true)
+		const fullText = source.getFullText()
+		const extractedNodes: Array<ExtractedNode> = []
+
+		ts.forEachChild(source, (node: ts.Node) => {
+			const extractedNode: ExtractedNode = {}
+
+			const commentRanges = ts.getLeadingCommentRanges(fullText, node.getFullStart())
+			const blockComments = (commentRanges ?? [])
+				.filter((comment) => comment.kind === ts.SyntaxKind.MultiLineCommentTrivia)
+				.map((r) => {
+					return fullText.slice(r.pos, r.end)
+				})
+
+			if (node.kind === ts.SyntaxKind.FunctionDeclaration) {
+				const functionDeclarationNode = node as ts.FunctionDeclaration
+				extractedNode.snippet = formatFunctionDeclaration(functionDeclarationNode, fullText)
+				extractedNode.name = String(functionDeclarationNode?.name?.escapedText ?? 'unknown function')
+				extractedNode.type = 'function'
+			} else if (node.kind === ts.SyntaxKind.ClassDeclaration) {
+				const classDeclarationNode = node as ts.ClassDeclaration
+				extractedNode.name = String(classDeclarationNode?.name?.escapedText ?? 'unknown class')
+                extractedNode.type = 'class'
+			}
+
+			if (blockComments.length === 0) return
+
+			extractedNode.comment = blockComments[0]
+
+			extractedNodes.push(extractedNode)
+		})
+
+		if (extractedNodes.length === 0) continue
+
+		const targetPath = `docs/api/${path.basename(sourcePath, '.ts')}.md`
+
+		let content = ''
+
+		content += `## ${sourcePath}\n\n`
+
+		for (const entry of extractedNodes) {
+			content += '---\n'
+			if (entry.name) content += `### ${entry?.type ?? ''} / ${entry.name}\n`
+			if (entry.snippet) content += `\`\`\`ts\n${entry.snippet}\n\`\`\`\n\n`
+
+			const entryDescription = (entry?.comment ?? '')
+				.split('\n')
+				.map((line) => line.replace(/(\/\*)|(\*\/)|(\*)/g, '').trim())
+				.join('\n')
+
+			content += `${entryDescription}\n\n`
+		}
+
+		files.push({
+			sourcePath,
+			targetPath,
+			content,
+		})
+	}
+
+	await fs.writeFile(API_DOC_PATH, '# API documentation\n---\n')
+
+	for await (const item of files) {
+		await fs.appendFile(API_DOC_PATH, item.content)
+	}
+}
+
+generateDocumentation()
diff --git a/package.json b/package.json
index a4141bd..cf0c440 100644
--- a/package.json
+++ b/package.json
@@ -16,13 +16,14 @@
     "prepack": "yarn build",
     "prebuild": "rm -rf dist",
     "cli": "$SHELL ./script/run",
-    "lint": "rome format src tests && rome check src tests",
-    "lint:fix": "rome format src tests --write && rome check src tests --apply",
+    "lint": "rome format src tests docs && rome check src tests docs",
+    "lint:fix": "rome format src tests docs --write && rome check src tests docs --apply",
     "types:check": "yarn tsc --project . --noEmit",
     "test": "$SHELL ./script/test-suite",
     "test:integration": "$SHELL ./script/integration-tests",
     "build:ts": "tsc --project .",
-    "build": "$SHELL ./script/build"
+    "build": "$SHELL ./script/build",
+    "docs": "yarn dlx ts-node ./docs/generate.ts ./src"
   },
   "devDependencies": {
     "@types/node": "^18.15.10",
diff --git a/src/testComponents/matchers.ts b/src/testComponents/matchers.ts
index ff61ffe..340ebdf 100644
--- a/src/testComponents/matchers.ts
+++ b/src/testComponents/matchers.ts
@@ -3,13 +3,28 @@
  *
  * All the matchers defined and exported as part of the default export
  * of this file are available to each `expect` statement made in tests.
+ *
+ * A matcher's inverse is defined by its behaviour when the `negated` flag
+ * that is passed to it is truthy.
  */
 import assert from 'assert'
 
 import { type MatcherReport, type WithLength } from '../types'
 
 /*
- * Asserts whether value and other are strictly equal.
+ * `toEqual` asserts whether `value` and `other` are strictly equal.
+ *
+ * Once registered, it can be used as
+ *
+ * ```ts
+ * expect(value).toEqual(other)
+ * ```
+ *
+ * and in negated form
+ *
+ * ```ts
+ * expect(value).not.toEqual(other)
+ * ```
  */
 function toEqual(value: unknown, other: unknown, negated: boolean = false): MatcherReport {
 	if (negated) return toNotEqual(value, other)
@@ -26,7 +41,8 @@ function toEqual(value: unknown, other: unknown, negated: boolean = false): Matc
 }
 
 /*
- * Inverse of toEqual.
+ * `toNotEqual` is the inverse of `toEqual` and behaves the same way as
+ * `expect(...).not.toEqual(...)`. Negating it behaves like `toEqual`.
  */
 function toNotEqual(value: unknown, other: unknown, negated: boolean = false): MatcherReport {
 	if (negated) return toEqual(value, other)
@@ -50,7 +66,7 @@ function toBe(value: unknown, other: unknown, negated: boolean = false): Matcher
 }
 
 /*
- * Inverse ot toBe.
+ * Inverse of toBe.
  */
 function toNotBe(value: unknown, other: unknown, negated: boolean = false): MatcherReport {
 	if (negated) return toBe(value, other)
diff --git a/src/worker.ts b/src/worker.ts
index 900f520..1dc25dc 100644
--- a/src/worker.ts
+++ b/src/worker.ts
@@ -1,12 +1,3 @@
-import path from 'path'
-
-import { getContext, spawnProcess } from './utils'
-
-// TODO: What should be message protocol / format be?
-function formatMessage(results: string, failed: boolean): string {
-	return JSON.stringify({ results, failed })
-}
-
 /*
  * Worker runtime
  *
@@ -18,6 +9,28 @@ function formatMessage(results: string, failed: boolean): string {
  * decides to assign it and files assigned to the worker are only
  * touched by the worker assigned to them.
  */
+
+import path from 'path'
+
+import { getContext, spawnProcess } from './utils'
+
+function formatMessage(results: string, failed: boolean): string {
+	return JSON.stringify({ results, failed })
+}
+
+/*
+ * Entrypoint for the worker.
+ *
+ * Retrieves paths assigned to the worker from the arguments passed when
+ * calling the worker runtime and spawns processes to run the test file
+ * pointed at by each of the paths.
+ *
+ * This will spawn one process per file and each process will communicate back
+ * to the worker's parent process as it finishes.
+ *
+ * If the `TS` flag is passed, the worker runs the test file using ts-node
+ * for Typescript compatibility.
+ */
 async function work() {
 	if (process?.send === undefined) throw Error('No process global found')
 	const tsMode = Boolean(process.env.TS === '1')