diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a366fb9..40b8318 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,7 +26,10 @@ jobs:
       - name: Install dependencies
         run: yarn --frozen-lockfile
 
-      - name: ESLint
+      - name: Typescript check
+        run: yarn tsc
+
+      - name: Biome lint check
         run: yarn lint
 
       - name: Unit tests
diff --git a/biome.json b/biome.json
new file mode 100644
index 0000000..6bf6de3
--- /dev/null
+++ b/biome.json
@@ -0,0 +1,48 @@
+{
+  "$schema": "./node_modules/@biomejs/biome/configuration_schema.json",
+  "files": {
+    "includes": [
+      "src/**/*.ts"
+    ]
+  },
+  "formatter": {
+    "enabled": true,
+    "formatWithErrors": false,
+    "indentStyle": "space",
+    "indentWidth": 2,
+    "lineEnding": "lf",
+    "lineWidth": 100,
+    "attributePosition": "auto"
+  },
+  "linter": {
+    "enabled": true,
+    "rules": {
+      "recommended": true,
+      "complexity": {
+        "noForEach": "off",
+        "noUselessSwitchCase": "off"
+      },
+      "a11y": {
+        "noSvgWithoutTitle": "off"
+      },
+      "suspicious": {
+        "noArrayIndexKey": "warn",
+        "noDoubleEquals": "off"
+      },
+      "style": {
+        "useImportType": "warn"
+      }
+    }
+  },
+  "javascript": {
+    "formatter": {
+      "quoteProperties": "asNeeded",
+      "semicolons": "asNeeded",
+      "arrowParentheses": "always",
+      "bracketSpacing": true,
+      "bracketSameLine": false,
+      "quoteStyle": "single",
+      "attributePosition": "auto"
+    }
+  }
+}
diff --git a/package.json b/package.json
index 273d613..97ef87c 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,8 @@
     "start": "tsc --watch",
     "prepare": "tsc",
     "coverage": "jest --coverage",
-    "lint": "tsc && prettier --list-different --write src tests",
+    "tsc": "tsc --noEmit",
+    "lint": "biome lint --diagnostic-level=error src",
     "test": "jest"
   },
   "repository": {
@@ -39,26 +40,20 @@
   },
   "devDependencies": {
     "@arethetypeswrong/cli": "0.15.4",
+    "@biomejs/biome": "2.0.4",
     "@types/jest": "29.5.12",
     "@types/node": "20.12.5",
     "expect-type": "^0.19.0",
     "husky": "9.0.11",
     "jest": "29.7.0",
-    "prettier": "3.2.5",
     "ts-jest": "29.1.2",
     "typescript": "5.2.2"
   },
   "author": "Aaron Franks",
   "license": "MIT",
-  "prettier": {
-    "printWidth": 100,
-    "semi": false,
-    "singleQuote": true,
-    "trailingComma": "all"
-  },
   "husky": {
     "hooks": {
-      "pre-commit": "yarn lint",
+      "pre-commit": "yarn lint && yarn tsc",
       "pre-push": "yarn test"
     }
   }
diff --git a/src/core.ts b/src/core.ts
index 6bbefbc..214e28c 100644
--- a/src/core.ts
+++ b/src/core.ts
@@ -1,5 +1,5 @@
 import { EnvError, EnvMissingError } from './errors'
-import { CleanOptions, SpecsOutput, Spec, ValidatorSpec } from './types'
+import type { CleanOptions, SpecsOutput, Spec, ValidatorSpec } from './types'
 import { defaultReporter } from './reporter'
 
 export const testOnlySymbol = Symbol('envalid - test only')
@@ -56,7 +56,7 @@ export function getSanitizedEnv<S>(
   specs: S,
   options: CleanOptions<SpecsOutput<S>> = {},
 ): SpecsOutput<S> {
-  let cleanedEnv = {} as SpecsOutput<S>
+  const cleanedEnv = {} as SpecsOutput<S>
   const castedSpecs = specs as unknown as Record<keyof S, ValidatorSpec<unknown>>
   const errors = {} as Record<keyof S, Error>
   const varKeys = Object.keys(castedSpecs) as Array<keyof S>
@@ -72,7 +72,7 @@ export function getSanitizedEnv<S>(
       if (rawValue === undefined) {
         // Use devDefault values only if NODE_ENV was explicitly set, and isn't 'production'
         const usingDevDefault =
-          rawNodeEnv && rawNodeEnv !== 'production' && spec.hasOwnProperty('devDefault')
+          rawNodeEnv && rawNodeEnv !== 'production' && Object.hasOwn(spec, 'devDefault')
 
         if (usingDevDefault) {
           cleanedEnv[k] = spec.devDefault
diff --git a/src/envalid.ts b/src/envalid.ts
index c0c453c..2c97072 100644
--- a/src/envalid.ts
+++ b/src/envalid.ts
@@ -1,4 +1,4 @@
-import { CleanedEnv, CleanOptions } from './types'
+import type { CleanedEnv, CleanOptions } from './types'
 import { getSanitizedEnv, testOnlySymbol } from './core'
 import { applyDefaultMiddleware } from './middleware'
 
diff --git a/src/makers.ts b/src/makers.ts
index 59ea76e..31e941c 100644
--- a/src/makers.ts
+++ b/src/makers.ts
@@ -1,4 +1,4 @@
-import { Spec, BaseValidator, StructuredValidator, ExactValidator } from './types'
+import type { Spec, BaseValidator, StructuredValidator, ExactValidator } from './types'
 
 const internalMakeValidator = <T>(parseFn: (input: string) => T) => {
   return (spec?: Spec<unknown>) => ({ ...spec, _parse: parseFn })
diff --git a/src/middleware.ts b/src/middleware.ts
index 2287e21..6570eea 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -1,4 +1,4 @@
-import { CleanedEnvAccessors, StrictProxyMiddlewareOptions } from './types'
+import type { CleanedEnvAccessors, StrictProxyMiddlewareOptions } from './types'
 
 export const strictProxyMiddleware = <T extends object>(
   envObj: T,
@@ -43,7 +43,7 @@ export const strictProxyMiddleware = <T extends object>(
         return target[name]
       }
 
-      const varExists = target.hasOwnProperty(name)
+      const varExists = Object.hasOwn(target, name)
       if (!varExists) {
         if (typeof rawEnv === 'object' && rawEnv?.hasOwnProperty?.(name)) {
           throw new ReferenceError(
diff --git a/src/reporter.ts b/src/reporter.ts
index 9e611b8..0b3b53e 100644
--- a/src/reporter.ts
+++ b/src/reporter.ts
@@ -1,6 +1,5 @@
-/* eslint-disable no-console */
 import { EnvMissingError } from './errors'
-import { ReporterOptions } from './types'
+import type { ReporterOptions } from './types'
 
 type Errors<T> = Partial<Record<keyof T, Error>>
 type Logger = (data: any, ...args: any[]) => void
diff --git a/src/validators.ts b/src/validators.ts
index 3272bce..10f0e95 100644
--- a/src/validators.ts
+++ b/src/validators.ts
@@ -5,7 +5,7 @@ import { makeExactValidator, makeStructuredValidator, makeValidator } from './ma
 const isFQDN = (input: string) => {
   if (!input.length) return false
   const parts = input.split('.')
-  for (let part, i = 0; i < parts.length; i++) {
+  for (let part: string, i = 0; i < parts.length; i++) {
     part = parts[i]
     if (!/^[a-z\u00a1-\uffff0-9-]+$/i.test(part)) return false
     if (/[\uff01-\uff5e]/.test(part)) return false // disallow full-width chars
diff --git a/tests/basics.test.ts b/tests/basics.test.ts
index a06c49b..a5f70d1 100644
--- a/tests/basics.test.ts
+++ b/tests/basics.test.ts
@@ -1,4 +1,4 @@
-import { cleanEnv, str, num, testOnly, ReporterOptions } from '../src'
+import { cleanEnv, str, num, testOnly, type ReporterOptions } from '../src'
 import { assertPassthrough } from './utils'
 import { expectTypeOf } from 'expect-type'
 
diff --git a/tests/middleware.test.ts b/tests/middleware.test.ts
index 857428c..29768a7 100644
--- a/tests/middleware.test.ts
+++ b/tests/middleware.test.ts
@@ -106,8 +106,8 @@ describe('proxy middleware', () => {
       },
     )
 
-    expect(env.hasOwnProperty('FOO')).toEqual(true)
-    expect(env.hasOwnProperty('BAR')).toEqual(false)
+    expect(Object.hasOwn(env, 'FOO')).toEqual(true)
+    expect(Object.hasOwn(env, 'BAR')).toEqual(false)
   })
 
   test('proxy does not error out on .length checks (#70)', () => {
diff --git a/tests/types.test.ts b/tests/types.test.ts
index abb7f40..5ddd036 100644
--- a/tests/types.test.ts
+++ b/tests/types.test.ts
@@ -3,10 +3,10 @@ import {
   str,
   bool,
   num,
-  RequiredValidatorSpec,
-  OptionalValidatorSpec,
+  type RequiredValidatorSpec,
+  type OptionalValidatorSpec,
   json,
-  CleanedEnvAccessors,
+  type CleanedEnvAccessors,
 } from '../src'
 import { expectTypeOf } from 'expect-type'
 import { makeStructuredValidator, makeValidator } from '../src/makers'
diff --git a/tests/utils.ts b/tests/utils.ts
index 5eba3ec..2309713 100644
--- a/tests/utils.ts
+++ b/tests/utils.ts
@@ -1,4 +1,4 @@
-import { cleanEnv, ValidatorSpec } from '../src'
+import { cleanEnv, type ValidatorSpec } from '../src'
 
 // Ensure that a given environment spec passes through all values from the given
 // env object
diff --git a/tsconfig.json b/tsconfig.json
index e2e55a4..c81562e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -12,9 +12,13 @@
     "noUnusedLocals": true,
     "noUnusedParameters": true,
     "noImplicitReturns": true,
-    "lib": ["es2019"]
+    "lib": [
+      "es2022"
+    ]
   },
-  "include": ["src"],
+  "include": [
+    "src"
+  ],
   "exclude": [
     "node_modules",
     "**/node_modules/*"
diff --git a/yarn.lock b/yarn.lock
index be8b543..9f747c3 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -328,6 +328,60 @@
   resolved "https://registry.yarnpkg.com/@bcoe/v8-coverage/-/v8-coverage-0.2.3.tgz#75a2e8b51cb758a7553d6804a5932d7aace75c39"
   integrity sha512-0hYQ8SB4Db5zvZB4axdMHGwEaQjkZzFjQiN9LVYvIFB2nSUHW9tYpxWriPrWDASIxiaXax83REcLxuSdnGPZtw==
 
+"@biomejs/biome@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/biome/-/biome-2.0.4.tgz#2abd3815d42ca674857c6be6ab4b7dd7098c9518"
+  integrity sha512-DNA++xe+E7UugTvI/HhzSFl6OwrVgU8SIV0Mb2fPtWPk2/oTr4eOSA5xy1JECrvgJeYxurmUBOS49qxv/OUkrQ==
+  optionalDependencies:
+    "@biomejs/cli-darwin-arm64" "2.0.4"
+    "@biomejs/cli-darwin-x64" "2.0.4"
+    "@biomejs/cli-linux-arm64" "2.0.4"
+    "@biomejs/cli-linux-arm64-musl" "2.0.4"
+    "@biomejs/cli-linux-x64" "2.0.4"
+    "@biomejs/cli-linux-x64-musl" "2.0.4"
+    "@biomejs/cli-win32-arm64" "2.0.4"
+    "@biomejs/cli-win32-x64" "2.0.4"
+
+"@biomejs/cli-darwin-arm64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-darwin-arm64/-/cli-darwin-arm64-2.0.4.tgz#2def86a792b1c01490e864b52a03af47ea326502"
+  integrity sha512-r5McIUMMiedwJ2rltuXhj0+w0W7IJLpkOS+OGCVZQQOOcrGY9gUSUmOo7O6Z7P0vlv5YYZkPbi+qR9MDDWRBSw==
+
+"@biomejs/cli-darwin-x64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-darwin-x64/-/cli-darwin-x64-2.0.4.tgz#eece80ae03e9456c2053613c5965a4421903bcf4"
+  integrity sha512-aV5Zc/3E3aXFbrjK1IgCMEQc+6PCkBL+NS+vtjoNM2VPFeM5OL5Q82BI4YZyPnebj+k42BPIoYtz0jJ95PGRRg==
+
+"@biomejs/cli-linux-arm64-musl@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-linux-arm64-musl/-/cli-linux-arm64-musl-2.0.4.tgz#92bdaada9ef465c9762c6ddd4a8edabb5a31b698"
+  integrity sha512-cNukq2PthoOa7quqaKoEFz4Zd1pDPJGfTR5jVyk9Z9iFHEm6TI7+7eeIs3aYcEuuJPNFR9xhJ4Uj3E2iUWkV3A==
+
+"@biomejs/cli-linux-arm64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-linux-arm64/-/cli-linux-arm64-2.0.4.tgz#2c3b018104164a4df883a48929033f34f51771eb"
+  integrity sha512-nlJhf7DyuajMj+S7Ygum59cbrHvI/nSRvedfJcEIx4X7SsiZjpRUiC5XtEn77kg7NIKq/KqG5roQIHkmjuFHCw==
+
+"@biomejs/cli-linux-x64-musl@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-linux-x64-musl/-/cli-linux-x64-musl-2.0.4.tgz#6ce9e45ed186ee85ee3f9c9f6ddb7673a917f28f"
+  integrity sha512-oWQALSbp8xF0t/wiHU2zdkZOpIHyaI9QxQv0Ytty9GAKsCGP6pczp8qyKD/P49iGJdDozHp5KiuQPxs33APhyA==
+
+"@biomejs/cli-linux-x64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-linux-x64/-/cli-linux-x64-2.0.4.tgz#102ffb44892c31fef2eb4e4e273953d6eb22c05f"
+  integrity sha512-jlzrNZ+OzN9wvp2RL3cl5Y4NiV7xSU+QV5A8bWXke1on3jKy7QbXajybSjVQ6aFw1gdrqkO/W8xV5HODhIMT4g==
+
+"@biomejs/cli-win32-arm64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-win32-arm64/-/cli-win32-arm64-2.0.4.tgz#d0b109a2b449c774f4236c0d25a3065e390e1d75"
+  integrity sha512-/PbNhMJo9ONja7hOxLlifM/qgeHpRD9bF2flTz5KIrXnQqpuegaRuwP/HYdJ9TFkTKFjHkPLoE4onOz3HIT5CQ==
+
+"@biomejs/cli-win32-x64@2.0.4":
+  version "2.0.4"
+  resolved "https://registry.yarnpkg.com/@biomejs/cli-win32-x64/-/cli-win32-x64-2.0.4.tgz#ab504167d41c27727a61653ccb0f4e9f467b8bbc"
+  integrity sha512-dIM4SgO4/Rmsb4X7fwKtciQ682SZDSC1lm42uSM9gt8zNqBIeTaqsMc6eO1DpxYWMlAb/n2SML9+HUHmCib7NA==
+
 "@colors/colors@1.5.0":
   version "1.5.0"
   resolved "https://registry.yarnpkg.com/@colors/colors/-/colors-1.5.0.tgz#bb504579c1cae923e6576a4f5da43d25f97bdbd9"
@@ -2038,11 +2092,6 @@ pkg-dir@^4.2.0:
   dependencies:
     find-up "^4.0.0"
 
-prettier@3.2.5:
-  version "3.2.5"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.2.5.tgz#e52bc3090586e824964a8813b09aba6233b28368"
-  integrity sha512-3/GWa9aOC0YeD7LUfvOG2NiDyhOWRvt1k+rcKhOuYnMY24iiCphgneUfJDyFXd6rZCAnuLBv6UeAULtrhT/F4A==
-
 pretty-format@^29.0.0, pretty-format@^29.7.0:
   version "29.7.0"
   resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-29.7.0.tgz#ca42c758310f365bfa71a0bda0a807160b776812"