diff --git a/packages/quill/src/core.ts b/packages/quill/src/core.ts
index 982f72c6d3..77816b5644 100644
--- a/packages/quill/src/core.ts
+++ b/packages/quill/src/core.ts
@@ -1,6 +1,7 @@
-import Quill from './core/quill.js';
+import Quill, { Parchment, Range } from './core/quill.js';
 import type {
   DebugLevel,
+  EmitterSource,
   ExpandedQuillOptions,
   QuillOptions,
 } from './core/quill.js';
@@ -22,8 +23,8 @@ import Delta, { Op, OpIterator, AttributeMap } from 'quill-delta';
 import Input from './modules/input.js';
 import UINode from './modules/uiNode.js';
 
-export { Delta, Op, OpIterator, AttributeMap };
-export type { DebugLevel, ExpandedQuillOptions, QuillOptions };
+export { Delta, Op, OpIterator, AttributeMap, Parchment, Range };
+export type { DebugLevel, EmitterSource, ExpandedQuillOptions, QuillOptions };
 
 Quill.register({
   'blots/block': Block,
diff --git a/packages/quill/src/core/quill.ts b/packages/quill/src/core/quill.ts
index 17219c33f7..59da9d0513 100644
--- a/packages/quill/src/core/quill.ts
+++ b/packages/quill/src/core/quill.ts
@@ -412,7 +412,13 @@ class Quill {
     length: number,
     name: string,
     value: unknown,
-    source: EmitterSource,
+    source?: EmitterSource,
+  ): Delta;
+  formatText(
+    index: number,
+    length: number,
+    formats: Record<string, unknown>,
+    source?: EmitterSource,
   ): Delta;
   formatText(
     index: number | { index: number; length: number },
@@ -568,24 +574,24 @@ class Quill {
     );
   }
 
-  insertText(index: number, text: string, source: EmitterSource): Delta;
+  insertText(index: number, text: string, source?: EmitterSource): Delta;
   insertText(
     index: number,
     text: string,
     formats: Record<string, unknown>,
-    source: EmitterSource,
+    source?: EmitterSource,
   ): Delta;
   insertText(
     index: number,
     text: string,
     name: string,
     value: unknown,
-    source: EmitterSource,
+    source?: EmitterSource,
   ): Delta;
   insertText(
     index: number,
     text: string,
-    name: string | Record<string, unknown> | EmitterSource,
+    name?: string | Record<string, unknown> | EmitterSource,
     value?: unknown,
     source?: EmitterSource,
   ): Delta {
@@ -647,8 +653,8 @@ class Quill {
     return this.emitter.once(...args);
   }
 
-  removeFormat(...args: Parameters<typeof overload>) {
-    const [index, length, , source] = overload(...args);
+  removeFormat(index: number, length: number, source?: EmitterSource) {
+    [index, length, , source] = overload(index, length, source);
     return modify.call(
       this,
       () => {
@@ -1027,6 +1033,7 @@ function shiftRange(
   return new Range(start, end - start);
 }
 
-export type { DebugLevel };
+export type { DebugLevel, EmitterSource };
+export { Parchment, Range };
 
 export { globalRegistry, expandConfig, overload, Quill as default };
diff --git a/packages/quill/src/quill.ts b/packages/quill/src/quill.ts
index fd364394c4..bc2535b1b8 100644
--- a/packages/quill/src/quill.ts
+++ b/packages/quill/src/quill.ts
@@ -1,5 +1,10 @@
-import Quill from './core.js';
-import type { DebugLevel, ExpandedQuillOptions, QuillOptions } from './core.js';
+import Quill, { Parchment, Range } from './core.js';
+import type {
+  DebugLevel,
+  EmitterSource,
+  ExpandedQuillOptions,
+  QuillOptions,
+} from './core.js';
 
 import { AlignClass, AlignStyle } from './formats/align.js';
 import {
@@ -109,6 +114,7 @@ Quill.register(
   true,
 );
 
-export type { DebugLevel, ExpandedQuillOptions, QuillOptions };
+export type { DebugLevel, EmitterSource, ExpandedQuillOptions, QuillOptions };
+export { Parchment, Range };
 
 export default Quill;
diff --git a/packages/quill/test/types/quill.test-d.ts b/packages/quill/test/types/quill.test-d.ts
new file mode 100644
index 0000000000..d7ae524188
--- /dev/null
+++ b/packages/quill/test/types/quill.test-d.ts
@@ -0,0 +1,211 @@
+import { assertType, expectTypeOf } from 'vitest';
+import Quill from '../../src/quill.js';
+import type { EmitterSource, Parchment, Range } from '../../src/quill.js';
+import Delta from 'quill-delta';
+import type { default as Block, BlockEmbed } from '../../src/blots/block.js';
+
+const quill = new Quill('#editor');
+
+{
+  quill.deleteText(0, 1);
+  quill.deleteText(0, 1, 'api');
+  quill.deleteText({ index: 0, length: 1 });
+  quill.deleteText({ index: 0, length: 1 }, 'api');
+}
+
+{
+  assertType<Delta>(quill.getContents());
+  assertType<Delta>(quill.getContents(1));
+  assertType<Delta>(quill.getContents(1, 2));
+}
+
+{
+  assertType<number>(quill.getLength());
+}
+
+{
+  assertType<string>(quill.getSemanticHTML());
+  assertType<string>(quill.getSemanticHTML(1));
+  assertType<string>(quill.getSemanticHTML(1, 2));
+}
+
+{
+  quill.insertEmbed(10, 'image', 'https://example.com/logo.png');
+  quill.insertEmbed(10, 'image', 'https://example.com/logo.png', 'api');
+}
+
+{
+  quill.insertText(0, 'Hello');
+  quill.insertText(0, 'Hello', 'api');
+  quill.insertText(0, 'Hello', 'bold', true);
+  quill.insertText(0, 'Hello', 'bold', true, 'api');
+  quill.insertText(5, 'Quill', {
+    color: '#ffff00',
+    italic: true,
+  });
+  quill.insertText(
+    5,
+    'Quill',
+    {
+      color: '#ffff00',
+      italic: true,
+    },
+    'api',
+  );
+}
+
+{
+  quill.enable();
+  quill.enable(true);
+}
+
+{
+  quill.disable();
+}
+
+{
+  assertType<boolean>(quill.editReadOnly(() => true));
+  assertType<string>(quill.editReadOnly(() => 'success'));
+}
+
+{
+  quill.setText('Hello World!');
+  quill.setText('Hello World!', 'api');
+}
+
+{
+  quill.updateContents([{ insert: 'Hello World!' }]);
+  quill.updateContents([{ insert: 'Hello World!' }], 'api');
+  quill.updateContents(new Delta().insert('Hello World!'));
+  quill.updateContents(new Delta().insert('Hello World!'), 'api');
+}
+
+{
+  quill.setContents([{ insert: 'Hello World!\n' }]);
+  quill.setContents([{ insert: 'Hello World!\n' }], 'api');
+  quill.setContents(new Delta().insert('Hello World!\n'));
+  quill.setContents(new Delta().insert('Hello World!\n'), 'api');
+}
+
+{
+  quill.format('bold', true);
+  quill.format('bold', true, 'api');
+}
+
+{
+  quill.formatText(0, 1, 'bold', true);
+  quill.formatText(0, 1, 'bold', true, 'api');
+  quill.formatText(0, 5, {
+    bold: false,
+    color: 'rgb(0, 0, 255)',
+  });
+  quill.formatText(
+    0,
+    5,
+    {
+      bold: false,
+      color: 'rgb(0, 0, 255)',
+    },
+    'api',
+  );
+}
+
+{
+  quill.formatLine(0, 1, 'bold', true);
+  quill.formatLine(0, 1, 'bold', true, 'api');
+  quill.formatLine(0, 5, {
+    bold: false,
+    color: 'rgb(0, 0, 255)',
+  });
+  quill.formatLine(
+    0,
+    5,
+    {
+      bold: false,
+      color: 'rgb(0, 0, 255)',
+    },
+    'api',
+  );
+}
+
+{
+  quill.getFormat();
+  quill.getFormat(1);
+  quill.getFormat(1, 10);
+  quill.getFormat({ index: 1, length: 1 });
+}
+
+{
+  quill.removeFormat(3, 2);
+  quill.removeFormat(3, 2, 'user');
+}
+
+{
+  quill.getBounds(3, 2);
+}
+
+{
+  quill.getSelection();
+  quill.getSelection(true);
+}
+
+{
+  quill.setSelection(1, 2);
+  quill.setSelection(1, 2, 'api');
+  quill.setSelection({ index: 1, length: 2 });
+  quill.setSelection({ index: 1, length: 2 }, 'api');
+}
+
+{
+  quill.scrollSelectionIntoView();
+}
+
+{
+  quill.blur();
+}
+
+{
+  quill.focus();
+}
+
+{
+  assertType<boolean>(quill.hasFocus());
+}
+
+{
+  quill.update();
+  quill.update('user');
+}
+
+{
+  quill.scrollRectIntoView({ left: 0, right: 0, top: 0, bottom: 0 });
+}
+
+{
+  quill.on('text-change', (delta, oldDelta, source) => {
+    expectTypeOf<Delta>(delta);
+    expectTypeOf<Delta>(oldDelta);
+    expectTypeOf<EmitterSource>(source);
+  });
+}
+
+{
+  quill.on('selection-change', (range, oldRange, source) => {
+    expectTypeOf<Range>(range);
+    expectTypeOf<Range>(oldRange);
+    expectTypeOf<EmitterSource>(source);
+  });
+}
+
+{
+  assertType<[Parchment.LeafBlot | null, number]>(quill.getLeaf(0));
+}
+
+{
+  assertType<[BlockEmbed | Block | null, number]>(quill.getLine(0));
+}
+
+{
+  assertType<(BlockEmbed | Block)[]>(quill.getLines(0));
+  assertType<(BlockEmbed | Block)[]>(quill.getLines(0, 10));
+}
diff --git a/packages/quill/test/unit/core/quill.spec.ts b/packages/quill/test/unit/core/quill.spec.ts
index dc17087b96..ca9f413afc 100644
--- a/packages/quill/test/unit/core/quill.spec.ts
+++ b/packages/quill/test/unit/core/quill.spec.ts
@@ -120,20 +120,36 @@ describe('Quill', () => {
       );
     });
 
-    test('formatText()', () => {
-      const { quill, oldDelta } = setup();
-      // @ts-expect-error
-      quill.formatText(3, 2, 'bold', true);
-      const change = new Delta().retain(3).retain(2, { bold: true });
-      expect(quill.root.innerHTML).toMatchInlineSnapshot(
-        '"<p>012<strong>3<em>4</em></strong><em>5</em>67</p>"',
-      );
-      expect(quill.emitter.emit).toHaveBeenCalledWith(
-        Emitter.events.TEXT_CHANGE,
-        change,
-        oldDelta,
-        Emitter.sources.API,
-      );
+    describe('formatText()', () => {
+      test('single format', () => {
+        const { quill, oldDelta } = setup();
+        quill.formatText(3, 2, 'bold', true);
+        const change = new Delta().retain(3).retain(2, { bold: true });
+        expect(quill.root.innerHTML).toMatchInlineSnapshot(
+          '"<p>012<strong>3<em>4</em></strong><em>5</em>67</p>"',
+        );
+        expect(quill.emitter.emit).toHaveBeenCalledWith(
+          Emitter.events.TEXT_CHANGE,
+          change,
+          oldDelta,
+          Emitter.sources.API,
+        );
+      });
+
+      test('format object', () => {
+        const { quill, oldDelta } = setup();
+        quill.formatText(3, 2, { bold: true });
+        const change = new Delta().retain(3).retain(2, { bold: true });
+        expect(quill.root.innerHTML).toMatchInlineSnapshot(
+          '"<p>012<strong>3<em>4</em></strong><em>5</em>67</p>"',
+        );
+        expect(quill.emitter.emit).toHaveBeenCalledWith(
+          Emitter.events.TEXT_CHANGE,
+          change,
+          oldDelta,
+          Emitter.sources.API,
+        );
+      });
     });
 
     test('insertEmbed()', () => {
@@ -155,7 +171,6 @@ describe('Quill', () => {
 
     test('insertText()', () => {
       const { quill, oldDelta } = setup();
-      // @ts-expect-error
       quill.insertText(5, '|', 'bold', true);
       const change = new Delta()
         .retain(5)
@@ -205,7 +220,6 @@ describe('Quill', () => {
 
     test('removeFormat()', () => {
       const { quill, oldDelta } = setup();
-      // @ts-expect-error
       quill.removeFormat(5, 1);
       const change = new Delta().retain(5).retain(1, { italic: null });
       expect(quill.root.innerHTML).toMatchInlineSnapshot(
@@ -261,7 +275,6 @@ describe('Quill', () => {
 
     test('api text insert', () => {
       const { quill, oldDelta } = setup();
-      // @ts-expect-error
       quill.insertText(2, '!');
       const delta = new Delta().retain(2).insert('!');
       expect(quill.emitter.emit).toHaveBeenCalledWith(
diff --git a/packages/quill/test/unit/modules/history.spec.ts b/packages/quill/test/unit/modules/history.spec.ts
index 28c69ce14e..cfaaca37cd 100644
--- a/packages/quill/test/unit/modules/history.spec.ts
+++ b/packages/quill/test/unit/modules/history.spec.ts
@@ -88,7 +88,6 @@ describe('History', () => {
     test('limits undo stack size', () => {
       const { quill } = setup({ delay: 0, maxStack: 2 });
       ['A', 'B', 'C'].forEach((text) => {
-        // @ts-expect-error
         quill.insertText(0, text);
       });
       expect(quill.history.stack.undo.length).toEqual(2);
@@ -96,7 +95,6 @@ describe('History', () => {
 
     test('emits selection changes', () => {
       const { quill } = setup({ delay: 0 });
-      // @ts-expect-error
       quill.insertText(0, 'foo');
       const change = vitest.fn();
       quill.on('selection-change', change);
diff --git a/packages/quill/test/unit/modules/syntax.spec.ts b/packages/quill/test/unit/modules/syntax.spec.ts
index afdd5a5148..cd1646bbb6 100644
--- a/packages/quill/test/unit/modules/syntax.spec.ts
+++ b/packages/quill/test/unit/modules/syntax.spec.ts
@@ -229,7 +229,6 @@ describe('Syntax', () => {
 
       test('modification', async () => {
         const quill = createQuill();
-        // @ts-expect-error
         quill.formatText(2, 3, 'bold', true);
         await sleep(HIGHLIGHT_INTERVAL + 1);
         expect(quill.root).toEqualHTML(`
@@ -252,7 +251,6 @@ describe('Syntax', () => {
 
       test('removal', async () => {
         const quill = createQuill();
-        // @ts-expect-error
         quill.formatText(2, 3, 'bold', true);
         await sleep(HIGHLIGHT_INTERVAL + 1);
         quill.formatLine(0, 15, 'code-block', false);
@@ -270,7 +268,6 @@ describe('Syntax', () => {
       test('addition', async () => {
         const quill = createQuill();
         quill.setText('var test = 1;\n');
-        // @ts-expect-error
         quill.formatText(2, 3, 'bold', true);
         quill.formatLine(0, 1, 'code-block', 'javascript');
         await sleep(HIGHLIGHT_INTERVAL + 1);
diff --git a/packages/quill/test/unit/vitest.config.ts b/packages/quill/test/unit/vitest.config.ts
index 5b727f9db3..67cdfa0c4c 100644
--- a/packages/quill/test/unit/vitest.config.ts
+++ b/packages/quill/test/unit/vitest.config.ts
@@ -7,6 +7,10 @@ export default defineConfig({
   },
   test: {
     include: [resolve(__dirname, '**/*.spec.ts')],
+    typecheck: {
+      enabled: true,
+      include: [resolve(__dirname, '**/*.test-d.ts')],
+    },
     setupFiles: [
       resolve(__dirname, '__helpers__/expect.ts'),
       resolve(__dirname, '__helpers__/cleanup.ts'),
diff --git a/packages/website/content/docs/api.mdx b/packages/website/content/docs/api.mdx
index acd6263b6e..66d456eb76 100644
--- a/packages/website/content/docs/api.mdx
+++ b/packages/website/content/docs/api.mdx
@@ -154,7 +154,7 @@ Inserts text into the editor, optionally with a specified format or multiple [fo
 insertText(index: number, text: string, source: string = 'api'): Delta
 insertText(index: number, text: string, format: string, value: any,
            source: string = 'api'): Delta
-insertText(index: number, text: string, formats: { [String]: any },
+insertText(index: number, text: string, formats: { [name: string]: any },
            source: string = 'api'): Delta
 ```
 
@@ -265,7 +265,7 @@ Formats all lines in given range, returning a [Delta](/docs/delta/) representing
 formatLine(index: number, length: number, source: string = 'api'): Delta
 formatLine(index: number, length: number, format: string, value: any,
            source: string = 'api'): Delta
-formatLine(index: number, length: number, formats: { [String]: any },
+formatLine(index: number, length: number, formats: { [name: string]: any },
            source: string = 'api'): Delta
 ```
 
@@ -288,7 +288,7 @@ Formats text in the editor, returning a [Delta](/docs/delta/) representing the c
 formatText(index: number, length: number, source: string = 'api'): Delta
 formatText(index: number, length: number, format: string, value: any,
            source: string = 'api'): Delta
-formatText(index: number, length: number, formats: { [String]: any },
+formatText(index: number, length: number, formats: { [name: string]: any },
            source: string = 'api'): Delta
 ```
 
@@ -314,8 +314,8 @@ Retrieves common formatting of the text in the given range. For a format to be r
 **Methods**
 
 ```typescript
-getFormat(range: Range = current): { [String]: any }
-getFormat(index: number, length: number = 0): { [String]: any }
+getFormat(range: Range = current): Record<string, unknown>
+getFormat(index: number, length: number = 0): Record<string, unknown>
 ```
 
 **Examples**
@@ -528,7 +528,7 @@ Checks if editor has focus. Note focus on toolbar, tooltips, does not count as t
 **Methods**
 
 ```typescript
-hasFocus(): Boolean
+hasFocus(): boolean
 ```
 
 **Examples**
@@ -798,7 +798,7 @@ Returns the leaf [Blot](https://github.com/quilljs/parchment) at the specified i
 **Methods**
 
 ```typescript
-getLeaf(index: number): Blot
+getLeaf(index: number): [LeafBlot | null, number]
 ```
 
 **Examples**
@@ -819,7 +819,7 @@ Returns the line [Blot](https://github.com/quilljs/parchment) at the specified i
 **Methods**
 
 ```typescript
-getLine(index: number): [Blot, Number]
+getLine(index: number): [Block | BlockEmbed | null, number]
 ```
 
 **Examples**
@@ -839,8 +839,8 @@ Returns the lines contained within the specified location.
 **Methods**
 
 ```typescript
-getLines(index: number = 0, length: number = remaining): Blot[]
-getLines(range: Range): Blot[]
+getLines(index: number = 0, length: number = remaining): (Block | BlockEmbed)[]
+getLines(range: Range): (Block | BlockEmbed)[]
 ```
 
 **Examples**
@@ -863,7 +863,7 @@ Static method enabling logging messages at a given level: `'error'`, `'warn'`, `
 **Methods**
 
 ```typescript
-Quill.debug(level: string | Boolean)
+Quill.debug(level: string | boolean)
 ```
 
 **Examples**
@@ -905,9 +905,9 @@ Registers a module, theme, or format(s), making them available to be added to an
 **Methods**
 
 ```typescript
-Quill.register(format: Attributor | BlotDefinintion, supressWarning: Boolean = false)
-Quill.register(path: string, def: any, supressWarning: Boolean = false)
-Quill.register(defs: { [String]: any }, supressWarning: Boolean = false)
+Quill.register(format: Attributor | BlotDefinintion, supressWarning: boolean = false)
+Quill.register(path: string, def: any, supressWarning: boolean = false)
+Quill.register(defs: { [path: string]: any }, supressWarning: boolean = false)
 ```
 
 **Examples**