diff --git a/eslint.config.js b/eslint.config.js
index c6df6b2..79d8908 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -15,5 +15,12 @@ export default defineConfig([
       ecmaVersion: 2020,
       globals: globals.browser,
     },
+    rules: {
+      "@typescript-eslint/ban-ts-comment": [
+        "error", {
+          "ts-ignore": "allow-with-description"
+        }
+      ],
+    }
   },
 ])
diff --git a/package.json b/package.json
index 66fd148..ed9da2f 100644
--- a/package.json
+++ b/package.json
@@ -1,5 +1,6 @@
 {
   "name": "@hamradio/packet",
+  "type": "module",
   "version": "1.0.0",
   "description": "Low level packet parsing library (for radio protocols)",
   "keywords": [
diff --git a/src/index.ts b/src/index.ts
index 634a240..b2bcd20 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -770,3 +770,25 @@ export class Writer {
 }
 
 export { FieldType } from './types';
+export {
+  isBytes,
+  assertBytes,
+  bytesToHex,
+  hexToBytes,
+  bytesToBase64,
+  base64ToBytes,
+  U8,
+  U16,
+  U32,
+  I8,
+  I16,
+  I32,
+  F32,
+  F64,
+  type Encoding,
+  type HexEncoding,
+  type Base64Encoding,
+  type Base64RawEncoding,
+  type Base64URLEncoding,
+  type Base64RawURLEncoding,
+} from './utils';
diff --git a/src/utils.test.ts b/src/utils.test.ts
new file mode 100644
index 0000000..ec9defe
--- /dev/null
+++ b/src/utils.test.ts
@@ -0,0 +1,224 @@
+import { describe, expect, it } from 'vitest';
+import {
+  U8,
+  U16,
+  U32,
+  I8,
+  I16,
+  I32,
+  F32,
+  F64,
+  isBytes,
+  assertBytes,
+  bytesToHex,
+  hexToBytes,
+  bytesToBase64,
+  base64ToBytes,
+  decodeBytes,
+  encodeBytes,
+} from './utils';
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+describe('utils', () => {
+  const staticHexVectors = [
+    { bytes: Uint8Array.from([]), hex: '' },
+    { bytes: Uint8Array.from([0xbe]), hex: 'be' },
+    { bytes: Uint8Array.from([0xca, 0xfe]), hex: 'cafe' },
+    { bytes: Uint8Array.from(new Array(1024).fill(0x69)), hex: '69'.repeat(1024) },
+  ];
+
+  const buf = new ArrayBuffer(8);
+  const v8 = new Uint8Array(buf);
+  for (let i = 0; i < v8.length; i++) v8[i] = i + 1;
+
+  it('U8 from ArrayBuffer', () => {
+    const a8 = U8(buf);
+    expect(a8).toBeInstanceOf(Uint8Array);
+    expect(Array.from(a8)).toEqual([1,2,3,4,5,6,7,8]);
+  });
+
+  it('U8 from Uint8Array view', () => {
+    const sub = new Uint8Array(buf, 2, 4);
+    const s8 = U8(sub);
+    expect(Array.from(s8)).toEqual([3,4,5,6]);
+  });
+
+  it('U16 from ArrayBuffer', () => {
+    const a16 = U16(buf);
+    expect(a16).toBeInstanceOf(Uint16Array);
+    expect(a16.length).toBe(Math.floor(buf.byteLength / 2));
+  });
+
+  it('U16 from Uint8Array view', () => {
+    const sub = new Uint8Array(buf, 2, 4);
+    const s16 = U16(sub);
+    expect(s16.length).toBe(Math.floor(sub.byteLength / 2));
+  });
+
+  it('U32 from ArrayBuffer', () => {
+    const a32 = U32(buf);
+    expect(a32).toBeInstanceOf(Uint32Array);
+    expect(a32.length).toBe(Math.floor(buf.byteLength / 4));
+  });
+
+  it('U32 from Uint8Array view', () => {
+    const sub = new Uint8Array(buf, 4, 4);
+    const s32 = U32(sub);
+    expect(s32.length).toBe(Math.floor(sub.byteLength / 4));
+  });
+
+  it('I8 from ArrayBuffer and view', () => {
+    const buf = new ArrayBuffer(4);
+    const dv = new DataView(buf);
+    dv.setInt8(0, -5);
+    dv.setInt8(1, 120);
+    dv.setInt8(2, -128);
+    dv.setInt8(3, 127);
+
+    const a = I8(buf);
+    expect(Array.from(a)).toEqual([-5, 120, -128, 127]);
+
+    const sub = new Int8Array(buf, 1, 2);
+    const s = I8(sub);
+    expect(Array.from(s)).toEqual([120, -128]);
+  });
+
+  it('I16 from ArrayBuffer and misaligned view throws', () => {
+    const buf = new ArrayBuffer(6);
+    const dv = new DataView(buf);
+    dv.setInt16(0, -12345, true);
+    dv.setInt16(2, 12345, true);
+    dv.setInt16(4, 32767, true);
+
+    const a16 = I16(buf);
+    expect(a16.length).toBe(3);
+    expect(a16[0]).toBe(-12345);
+    expect(a16[1]).toBe(12345);
+    expect(a16[2]).toBe(32767);
+
+    const view = new Uint8Array(buf, 1, 4);
+    expect(() => I16(view)).toThrow();
+  });
+
+  it('I32 from ArrayBuffer and misaligned view throws', () => {
+    const buf = new ArrayBuffer(12);
+    const dv = new DataView(buf);
+    dv.setInt32(0, -0x1234567, true);
+    dv.setInt32(4, 0x1234567, true);
+
+    const a32 = I32(buf);
+    expect(a32[0]).toBe(-0x1234567);
+    expect(a32[1]).toBe(0x1234567);
+
+    const view = new Uint8Array(buf, 1, 8);
+    expect(() => I32(view)).toThrow();
+  });
+
+  it('F32/F64 from ArrayBuffer', () => {
+    const buf = new ArrayBuffer(16);
+    const dv = new DataView(buf);
+    dv.setFloat32(0, 3.14, true);
+    dv.setFloat32(4, -2.5, true);
+    dv.setFloat64(8, 1.23456789e3, true);
+
+    const f32 = F32(buf);
+    expect(f32[0]).toBeCloseTo(3.14, 5);
+    expect(f32[1]).toBeCloseTo(-2.5, 5);
+
+    const f64 = F64(buf);
+    expect(f64[1]).toBeCloseTo(1.23456789e3, 8);
+  });
+
+  it('isBytes', () => {
+    expect(isBytes(new Uint8Array([1,2]))).toBe(true);
+    expect(isBytes(new Uint16Array([1,2]) as unknown)).toBe(false);
+    expect(isBytes(new ArrayBuffer(2) as unknown)).toBe(false);
+  })
+
+  it('assertBytes', () => {
+    // assertBytes accepts a Uint8Array
+    expect(() => assertBytes(new Uint8Array([1,2]))).not.toThrow();
+    // assertBytes with length mismatch throws
+    expect(() => assertBytes(new Uint8Array([1,2]), 3)).toThrow();
+    // assertBytes with wrong type throws
+    expect(() => assertBytes(new Uint16Array([1,2]) as any)).toThrow();
+  });
+
+  it('hexToBytes / bytesToHex roundtrip', () => {
+    for (const v of staticHexVectors) {
+      expect(hexToBytes(v.hex)).toEqual(v.bytes);
+      expect(hexToBytes(v.hex.toUpperCase())).toEqual(v.bytes);
+      expect(bytesToHex(v.bytes)).toEqual(v.hex);
+      // encode -> decode
+      const h = bytesToHex(v.bytes);
+      expect(hexToBytes(h)).toEqual(v.bytes);
+    }
+  });
+
+  it('base64 encodings roundtrip and variants', () => {
+    const hello = new Uint8Array([72,101,108,108,111]); // 'Hello'
+    const b64 = bytesToBase64(hello, 'base64');
+    expect(base64ToBytes(b64)).toEqual(hello);
+
+    const b64raw = bytesToBase64(hello, 'base64raw');
+    expect(base64ToBytes(b64raw)).toEqual(hello);
+
+    const b64url = bytesToBase64(hello, 'base64url');
+    expect(base64ToBytes(b64url)).toEqual(hello);
+
+    const b64urlraw = bytesToBase64(hello, 'base64urlraw');
+    expect(base64ToBytes(b64urlraw)).toEqual(hello);
+  });
+
+  it('encodeBytes / decodeBytes round robin across encodings', () => {
+    const bytes = Uint8Array.from([0xde,0xad,0xbe,0xef]);
+    const encodings = ['hex','base64','base64raw','base64url','base64urlraw'] as const;
+    for (const enc of encodings) {
+      const s = encodeBytes(bytes, enc as any);
+      const out = decodeBytes(s, enc as any);
+      expect(out).toEqual(bytes);
+    }
+  });
+
+  it('throws on invalid inputs for hex/base64 decoders', () => {
+    expect(() => hexToBytes('z')).toThrow();
+    expect(() => base64ToBytes('??')).toThrow();
+    expect(() => decodeBytes('abc', 'unsupported' as any)).toThrow();
+  });
+
+  it('edge cases: offsets, odd lengths, url base64, empty and large roundtrips', () => {
+    // U16/U32 with subarray offset
+    const buf = new ArrayBuffer(6);
+    const v = new Uint8Array(buf);
+    v.set([1,2,3,4,5,6]);
+    const view = new Uint8Array(buf, 1, 4); // [2,3,4,5]
+    const u8 = U8(view);
+    expect(Array.from(u8)).toEqual([2,3,4,5]);
+    // Unaligned views cannot be reinterpreted as 16-bit/32-bit arrays on some
+    // platforms; U16/U32 will throw for misaligned offsets. Assert that behavior.
+    expect(() => U16(view)).toThrow();
+
+    // hexToBytes with odd length should throw
+    expect(() => hexToBytes('f')).toThrow();
+
+    // base64 url-safe without padding should be accepted
+    const sample = new Uint8Array([0x01,0x02,0x03,0xff]);
+    const raw = bytesToBase64(sample, 'base64raw');
+    // url variant
+    const url = bytesToBase64(sample, 'base64urlraw');
+    expect(base64ToBytes(raw)).toEqual(sample);
+    expect(base64ToBytes(url)).toEqual(sample);
+
+    // empty inputs
+    expect(bytesToHex(new Uint8Array([]))).toBe('');
+    expect(bytesToBase64(new Uint8Array([]), 'base64')).toBe('');
+
+    // large random roundtrip
+    const large = new Uint8Array(10000);
+    for (let i = 0; i < large.length; i++) large[i] = i & 0xff;
+    const h = bytesToHex(large);
+    expect(hexToBytes(h)).toEqual(large);
+    const b64 = bytesToBase64(large, 'base64raw');
+    expect(base64ToBytes(b64)).toEqual(large);
+  });
+});
diff --git a/src/utils.ts b/src/utils.ts
new file mode 100644
index 0000000..58936bb
--- /dev/null
+++ b/src/utils.ts
@@ -0,0 +1,163 @@
+export type TypedArray = Int8Array | Uint8ClampedArray | Uint8Array | Uint16Array | Int16Array | Uint32Array | Int32Array;
+
+export const U8 = (arr: ArrayBuffer | TypedArray): Uint8Array => {
+  if (arr instanceof ArrayBuffer) return new Uint8Array(arr);
+  return new Uint8Array(arr.buffer, arr.byteOffset, arr.byteLength);
+}
+
+export const I8 = (arr: ArrayBuffer | TypedArray): Int8Array => {
+  if (arr instanceof ArrayBuffer) return new Int8Array(arr);
+  return new Int8Array(arr.buffer, arr.byteOffset, arr.byteLength);
+}
+
+export const U16 = (arr: ArrayBuffer | TypedArray): Uint16Array => {
+  if (arr instanceof ArrayBuffer) return new Uint16Array(arr);
+  return new Uint16Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 2));
+}
+
+export const I16 = (arr: ArrayBuffer | TypedArray): Int16Array => {
+  if (arr instanceof ArrayBuffer) return new Int16Array(arr);
+  return new Int16Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 2));
+}
+
+export const U32 = (arr: ArrayBuffer | TypedArray): Uint32Array => {
+  if (arr instanceof ArrayBuffer) return new Uint32Array(arr);
+  return new Uint32Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 4));
+}
+
+export const I32 = (arr: ArrayBuffer | TypedArray): Int32Array => {
+  if (arr instanceof ArrayBuffer) return new Int32Array(arr);
+  return new Int32Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 4));
+}
+
+export const F32 = (arr: ArrayBuffer | TypedArray): Float32Array => {
+  if (arr instanceof ArrayBuffer) return new Float32Array(arr);
+  return new Float32Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 4));
+}
+
+export const F64 = (arr: ArrayBuffer | TypedArray): Float64Array => {
+  if (arr instanceof ArrayBuffer) return new Float64Array(arr);
+  return new Float64Array(arr.buffer, arr.byteOffset, Math.floor(arr.byteLength / 8));
+}
+
+export const isBytes = (bytes: unknown): boolean => {
+  return bytes instanceof Uint8Array || (ArrayBuffer.isView(bytes) && bytes.constructor.name === "Uint8Array");
+}
+
+export const assertBytes = (bytes: Uint8Array, length?: number, name: string = ""): void => {
+  const valid = isBytes(bytes);
+  const sized = (typeof length !== 'undefined') ? (bytes.byteLength === length) : true;
+  if (!valid || !sized) {
+    const expected = typeof length !== 'undefined' ? `Uint8Array of length ${length}` : 'Uint8Array';
+    const actual = valid ? `Uint8Array of length ${bytes.byteLength}` : typeof bytes;
+    throw new TypeError(`Expected ${name} to be ${expected}, got ${actual}`);
+  }
+}
+
+const hasHexMethods = (() =>
+  // @ts-ignore testing for builtins
+  'toHex' in Uint8Array.from([]) && typeof Uint8Array.from([])['toHex'] === 'function' &&
+  'fromHex' in Uint8Array && typeof Uint8Array.fromHex === 'function')();
+
+// Array where index 0xf0 (240) is mapped to string 'f0'
+const hexes = Array.from({ length: 256 }, (_, i) =>
+  i.toString(16).padStart(2, '0')
+);
+
+export type HexEncoding = 'hex';
+export type Base64Encoding = 'base64';
+export type Base64RawEncoding = 'base64raw';
+export type Base64URLEncoding = 'base64url';
+export type Base64RawURLEncoding = 'base64urlraw';
+export type Encoding = HexEncoding | Base64Encoding | Base64RawEncoding | Base64URLEncoding | Base64RawURLEncoding;
+
+export const bytesToHex = (bytes: Uint8Array, length?: number): string => {
+  assertBytes(bytes, (typeof length !== 'undefined') ? length * 2 : undefined, "bytes");
+  let hex = '';
+  for (const byte of bytes) {
+    hex += hexes[byte];
+  }
+  return hex;
+};
+
+export const hexToBytes = (hex: string): Uint8Array => {
+  if (typeof hex !== 'string' || hex.length % 2 !== 0 || !/^[0-9a-fA-F]*$/.test(hex)) {
+    throw new TypeError(`Expected hex string of even length, got ${hex}`);
+  }
+  if (hasHexMethods) {
+    // @ts-ignore using built-in hex methods if available
+    return Uint8Array.fromHex(hex);
+  }
+
+  const bytes = new Uint8Array(hex.length / 2);
+  for (let i = 0; i < hex.length; i += 2) {
+    bytes[i / 2] = parseInt(hex.slice(i, i + 2), 16);
+  }
+  return bytes;
+}
+
+export const bytesToBase64 = (bytes: Uint8Array, encoding: Base64Encoding | Base64RawEncoding | Base64URLEncoding | Base64RawURLEncoding): string => {
+  assertBytes(bytes, (typeof length !== 'undefined') ? length * 2 : undefined, "bytes");
+  const binary = String.fromCharCode(...bytes);
+  switch (encoding) {
+    case 'base64':
+      return btoa(binary);
+    case 'base64raw':
+      return btoa(binary).replace(/=+$/, '');
+    case 'base64url':
+      return btoa(binary).replace(/\+/g, '-').replace(/\//g, '_');
+    case 'base64urlraw':
+      return btoa(binary).replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
+    default:
+      throw new TypeError(`Unsupported encoding: ${encoding}`);
+  }
+}
+
+export const base64ToBytes = (b64: string): Uint8Array => {
+  if (typeof b64 !== "string") {
+    throw new TypeError(`Expected base64 string, got ${b64}`);
+  }
+  // Accept URL-safe base64 by replacing '-' with '+' and '_' with '/'
+  let normalized = b64.replace(/-/g, "+").replace(/_/g, "/");
+  // Pad with '=' to make length a multiple of 4
+  if (normalized.length % 4 !== 0) {
+    normalized += "=".repeat(4 - (normalized.length % 4));
+  }
+  if (!/^[A-Za-z0-9+/]*={0,2}$/.test(normalized)) {
+    throw new TypeError(`Expected base64 string, got ${b64}`);
+  }
+  const binary = atob(normalized);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i++) {
+    bytes[i] = binary.charCodeAt(i);
+  }
+  return bytes;
+};
+
+export const decodeBytes = (encoded: string, encoding: Encoding): Uint8Array => {
+  switch (encoding) {
+    case 'hex':
+      return hexToBytes(encoded);
+    case 'base64':
+    case 'base64raw':
+    case 'base64url':
+    case 'base64urlraw':
+      return base64ToBytes(encoded);
+    default:
+      throw new TypeError(`Unsupported encoding: ${encoding}`);
+  }
+}
+
+export const encodeBytes = (bytes: Uint8Array, encoding: Encoding): string => {
+  switch (encoding) {
+    case 'hex':
+      return bytesToHex(bytes);
+    case 'base64':
+    case 'base64raw':
+    case 'base64url':
+    case 'base64urlraw':
+      return bytesToBase64(bytes, encoding);
+    default:
+      throw new TypeError(`Unsupported encoding: ${encoding}`);
+  }
+}