diff --git a/src/environment.ts b/src/environment.ts
index 9be36e2..0522f53 100644
--- a/src/environment.ts
+++ b/src/environment.ts
@@ -1,5 +1,48 @@
-import { Buffer } from 'node:buffer'
-import { env } from 'node:process'
+import { base64Decode, base64Encode } from './util.ts'
+
+interface EnvironmentVariables {
+  delete: (key: string) => void
+  get: (key: string) => string | undefined
+  has: (key: string) => boolean
+  set: (key: string, value: string) => void
+  toObject: () => Record<string, string>
+}
+
+interface Globals {
+  Deno?: {
+    env: EnvironmentVariables
+  }
+  Netlify?: {
+    env: EnvironmentVariables
+  }
+  process?: {
+    env: Record<string, string>
+  }
+}
+
+/**
+ * Returns a cross-runtime interface for handling environment variables. It
+ * uses the `Netlify.env` global if available, otherwise looks for `Deno.env`
+ * and `process.env`.
+ */
+export const getEnvironment = (): EnvironmentVariables => {
+  const { Deno, Netlify, process } = globalThis as Globals
+
+  return (
+    Netlify?.env ??
+    Deno?.env ?? {
+      delete: (key: string) => delete process?.env[key],
+      get: (key: string) => process?.env[key],
+      has: (key: string) => Boolean(process?.env[key]),
+      set: (key: string, value: string) => {
+        if (process?.env) {
+          process.env[key] = value
+        }
+      },
+      toObject: () => process?.env ?? {},
+    }
+  )
+}
 
 declare global {
   // Using `var` so that the declaration is hoisted in such a way that we can
@@ -21,13 +64,13 @@ export interface EnvironmentContext {
 }
 
 export const getEnvironmentContext = (): EnvironmentContext => {
-  const context = globalThis.netlifyBlobsContext || env.NETLIFY_BLOBS_CONTEXT
+  const context = globalThis.netlifyBlobsContext || getEnvironment().get('NETLIFY_BLOBS_CONTEXT')
 
   if (typeof context !== 'string' || !context) {
     return {}
   }
 
-  const data = Buffer.from(context, 'base64').toString()
+  const data = base64Decode(context)
 
   try {
     return JSON.parse(data) as EnvironmentContext
@@ -39,9 +82,9 @@ export const getEnvironmentContext = (): EnvironmentContext => {
 }
 
 export const setEnvironmentContext = (context: EnvironmentContext) => {
-  const encodedContext = Buffer.from(JSON.stringify(context)).toString('base64')
+  const encodedContext = base64Encode(JSON.stringify(context))
 
-  env.NETLIFY_BLOBS_CONTEXT = encodedContext
+  getEnvironment().set('NETLIFY_BLOBS_CONTEXT', encodedContext)
 }
 
 export class MissingBlobsEnvironmentError extends Error {
diff --git a/src/lambda_compat.ts b/src/lambda_compat.ts
index a87fa6f..cbe3200 100644
--- a/src/lambda_compat.ts
+++ b/src/lambda_compat.ts
@@ -1,7 +1,6 @@
-import { Buffer } from 'node:buffer'
-
 import { EnvironmentContext, setEnvironmentContext } from './environment.ts'
 import type { LambdaEvent } from './types.ts'
+import { base64Decode } from './util.ts'
 
 interface BlobsEventData {
   token: string
@@ -9,8 +8,8 @@ interface BlobsEventData {
 }
 
 export const connectLambda = (event: LambdaEvent) => {
-  const rawData = Buffer.from(event.blobs, 'base64')
-  const data = JSON.parse(rawData.toString('ascii')) as BlobsEventData
+  const rawData = base64Decode(event.blobs)
+  const data = JSON.parse(rawData) as BlobsEventData
   const environmentContext: EnvironmentContext = {
     deployID: event.headers['x-nf-deploy-id'],
     edgeURL: data.url,
diff --git a/src/metadata.ts b/src/metadata.ts
index 3e4ef22..185398b 100644
--- a/src/metadata.ts
+++ b/src/metadata.ts
@@ -1,4 +1,4 @@
-import { Buffer } from 'node:buffer'
+import { base64Decode, base64Encode } from './util.ts'
 
 export type Metadata = Record<string, unknown>
 
@@ -12,7 +12,7 @@ export const encodeMetadata = (metadata?: Metadata) => {
     return null
   }
 
-  const encodedObject = Buffer.from(JSON.stringify(metadata)).toString('base64')
+  const encodedObject = base64Encode(JSON.stringify(metadata))
   const payload = `b64;${encodedObject}`
 
   if (METADATA_HEADER_EXTERNAL.length + payload.length > METADATA_MAX_SIZE) {
@@ -28,7 +28,7 @@ export const decodeMetadata = (header: string | null): Metadata => {
   }
 
   const encodedData = header.slice(BASE64_PREFIX.length)
-  const decodedData = Buffer.from(encodedData, 'base64').toString()
+  const decodedData = base64Decode(encodedData)
   const metadata = JSON.parse(decodedData)
 
   return metadata
diff --git a/src/retry.ts b/src/retry.ts
index 9d6f8f2..fa38167 100644
--- a/src/retry.ts
+++ b/src/retry.ts
@@ -1,8 +1,7 @@
-import { env } from 'node:process'
-
+import { getEnvironment } from './environment.ts'
 import type { Fetcher } from './types.ts'
 
-const DEFAULT_RETRY_DELAY = env.NODE_ENV === 'test' ? 1 : 5000
+const DEFAULT_RETRY_DELAY = getEnvironment().get('NODE_ENV') === 'test' ? 1 : 5000
 const MIN_RETRY_DELAY = 1000
 const MAX_RETRY = 5
 const RATE_LIMIT_HEADER = 'X-RateLimit-Reset'
diff --git a/src/store.ts b/src/store.ts
index 430f028..2371ada 100644
--- a/src/store.ts
+++ b/src/store.ts
@@ -1,5 +1,3 @@
-import { Buffer } from 'node:buffer'
-
 import { ListResponse, ListResponseBlob } from './backend/list.ts'
 import { Client } from './client.ts'
 import type { ConsistencyMode } from './consistency.ts'
@@ -341,7 +339,7 @@ export class Store {
       throw new Error('Blob key must not start with forward slash (/).')
     }
 
-    if (Buffer.byteLength(key, 'utf8') > 600) {
+    if (new TextEncoder().encode(key).length > 600) {
       throw new Error(
         'Blob key must be a sequence of Unicode characters whose UTF-8 encoding is at most 600 bytes long.',
       )
@@ -363,7 +361,7 @@ export class Store {
       throw new Error('Store name must not contain forward slashes (/).')
     }
 
-    if (Buffer.byteLength(name, 'utf8') > 64) {
+    if (new TextEncoder().encode(name).length > 64) {
       throw new Error(
         'Store name must be a sequence of Unicode characters whose UTF-8 encoding is at most 64 bytes long.',
       )
diff --git a/src/util.ts b/src/util.ts
index 167c631..ddc4d90 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -19,3 +19,25 @@ export const collectIterator = async <T>(iterator: AsyncIterable<T>): Promise<T[
 export const isNodeError = (error: unknown): error is NodeJS.ErrnoException => error instanceof Error
 
 export type Logger = (...message: unknown[]) => void
+
+export const base64Decode = (input: string) => {
+  // eslint-disable-next-line n/prefer-global/buffer
+  const { Buffer } = globalThis
+
+  if (Buffer) {
+    return Buffer.from(input, 'base64').toString()
+  }
+
+  return atob(input)
+}
+
+export const base64Encode = (input: string) => {
+  // eslint-disable-next-line n/prefer-global/buffer
+  const { Buffer } = globalThis
+
+  if (Buffer) {
+    return Buffer.from(input).toString('base64')
+  }
+
+  return btoa(input)
+}