diff --git a/.changeset/four-scissors-tie.md b/.changeset/four-scissors-tie.md
new file mode 100644
index 00000000..503dc296
--- /dev/null
+++ b/.changeset/four-scissors-tie.md
@@ -0,0 +1,6 @@
+---
+"@effect/platform-node": patch
+"@effect/platform": patch
+---
+
+use branded type for Headers
diff --git a/.changeset/many-rats-notice.md b/.changeset/many-rats-notice.md
new file mode 100644
index 00000000..18b6ddc7
--- /dev/null
+++ b/.changeset/many-rats-notice.md
@@ -0,0 +1,6 @@
+---
+"@effect/platform-node": patch
+"@effect/platform": patch
+---
+
+change UrlParams to ReadonlyArray
diff --git a/docs/platform/Http/Headers.ts.md b/docs/platform/Http/Headers.ts.md
index 2a74be41..b38814e3 100644
--- a/docs/platform/Http/Headers.ts.md
+++ b/docs/platform/Http/Headers.ts.md
@@ -15,15 +15,20 @@ Added in v1.0.0
 - [combinators](#combinators)
   - [get](#get)
   - [has](#has)
+  - [merge](#merge)
   - [remove](#remove)
   - [set](#set)
   - [setAll](#setall)
 - [constructors](#constructors)
   - [empty](#empty)
   - [fromInput](#frominput)
+  - [unsafeFromRecord](#unsafefromrecord)
 - [models](#models)
-  - [Headers (interface)](#headers-interface)
+  - [Headers (type alias)](#headers-type-alias)
   - [Input (type alias)](#input-type-alias)
+- [type ids](#type-ids)
+  - [HeadersTypeId](#headerstypeid)
+  - [HeadersTypeId (type alias)](#headerstypeid-type-alias)
 
 ---
 
@@ -52,6 +57,19 @@ export declare const has: { (key: string): (self: Headers) => boolean; (self: He
 
 Added in v1.0.0
 
+## merge
+
+**Signature**
+
+```ts
+export declare const merge: {
+  (headers: Headers): (self: Headers) => Headers
+  (self: Headers, headers: Headers): Headers
+}
+```
+
+Added in v1.0.0
+
 ## remove
 
 **Signature**
@@ -107,14 +125,24 @@ export declare const fromInput: (input?: Input) => Headers
 
 Added in v1.0.0
 
+## unsafeFromRecord
+
+**Signature**
+
+```ts
+export declare const unsafeFromRecord: (input: ReadonlyRecord.ReadonlyRecord<string>) => Headers
+```
+
+Added in v1.0.0
+
 # models
 
-## Headers (interface)
+## Headers (type alias)
 
 **Signature**
 
 ```ts
-export interface Headers extends ReadonlyRecord.ReadonlyRecord<string> {}
+export type Headers = Brand.Branded<ReadonlyRecord.ReadonlyRecord<string>, HeadersTypeId>
 ```
 
 Added in v1.0.0
@@ -124,7 +152,29 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export type Input = Headers | Iterable<readonly [string, string]>
+export type Input = ReadonlyRecord.ReadonlyRecord<string> | Iterable<readonly [string, string]>
+```
+
+Added in v1.0.0
+
+# type ids
+
+## HeadersTypeId
+
+**Signature**
+
+```ts
+export declare const HeadersTypeId: typeof HeadersTypeId
+```
+
+Added in v1.0.0
+
+## HeadersTypeId (type alias)
+
+**Signature**
+
+```ts
+export type HeadersTypeId = typeof HeadersTypeId
 ```
 
 Added in v1.0.0
diff --git a/docs/platform/Http/Platform.ts.md b/docs/platform/Http/Platform.ts.md
index ae9dfa88..a2828e99 100644
--- a/docs/platform/Http/Platform.ts.md
+++ b/docs/platform/Http/Platform.ts.md
@@ -36,7 +36,7 @@ export declare const make: (impl: {
     path: string,
     status: number,
     statusText: string | undefined,
-    headers: Record<string, string>,
+    headers: Headers.Headers,
     start: number,
     end: number | undefined,
     contentLength: number
@@ -45,7 +45,7 @@ export declare const make: (impl: {
     file: Body.Body.FileLike,
     status: number,
     statusText: string | undefined,
-    headers: Record<string, string>,
+    headers: Headers.Headers,
     options?: FileSystem.StreamOptions | undefined
   ) => ServerResponse.ServerResponse
 }) => Effect.Effect<FileSystem.FileSystem | Etag.Generator, never, Platform>
diff --git a/docs/platform/Http/UrlParams.ts.md b/docs/platform/Http/UrlParams.ts.md
index a6c3115a..65bfbcea 100644
--- a/docs/platform/Http/UrlParams.ts.md
+++ b/docs/platform/Http/UrlParams.ts.md
@@ -149,7 +149,7 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export type Input = UrlParams | Readonly<Record<string, string>> | Iterable<readonly [string, string]> | URLSearchParams
+export type Input = Readonly<Record<string, string>> | Iterable<readonly [string, string]> | URLSearchParams
 ```
 
 Added in v1.0.0
@@ -159,7 +159,7 @@ Added in v1.0.0
 **Signature**
 
 ```ts
-export interface UrlParams extends Chunk.Chunk<[string, string]> {}
+export interface UrlParams extends ReadonlyArray<readonly [string, string]> {}
 ```
 
 Added in v1.0.0
diff --git a/packages/platform-node/src/internal/http/platform.ts b/packages/platform-node/src/internal/http/platform.ts
index d2dd615a..f8431886 100644
--- a/packages/platform-node/src/internal/http/platform.ts
+++ b/packages/platform-node/src/internal/http/platform.ts
@@ -1,3 +1,4 @@
+import * as Headers from "@effect/platform/Http/Headers"
 import * as Platform from "@effect/platform/Http/Platform"
 import * as ServerResponse from "@effect/platform/Http/ServerResponse"
 import { pipe } from "effect/Function"
@@ -24,11 +25,13 @@ export const make = Platform.make({
   },
   fileWebResponse(file, status, statusText, headers, _options) {
     return ServerResponse.raw(Readable.fromWeb(file.stream() as any), {
-      headers: {
-        ...headers,
-        "content-type": headers["content-type"] ?? Mime.getType(file.name) ?? "application/octet-stream",
-        "content-length": file.size.toString()
-      },
+      headers: Headers.merge(
+        headers,
+        Headers.unsafeFromRecord({
+          "content-type": headers["content-type"] ?? Mime.getType(file.name) ?? "application/octet-stream",
+          "content-length": file.size.toString()
+        })
+      ),
       status,
       statusText
     })
diff --git a/packages/platform/src/Http/Headers.ts b/packages/platform/src/Http/Headers.ts
index f350a8fa..a22f6212 100644
--- a/packages/platform/src/Http/Headers.ts
+++ b/packages/platform/src/Http/Headers.ts
@@ -1,28 +1,41 @@
 /**
  * @since 1.0.0
  */
+import type * as Brand from "effect/Brand"
 import { dual } from "effect/Function"
 import type * as Option from "effect/Option"
 import * as ReadonlyArray from "effect/ReadonlyArray"
 import * as ReadonlyRecord from "effect/ReadonlyRecord"
 
+/**
+ * @since 1.0.0
+ * @category type ids
+ */
+export const HeadersTypeId = Symbol.for("@effect/platform/Http/Headers")
+
+/**
+ * @since 1.0.0
+ * @category type ids
+ */
+export type HeadersTypeId = typeof HeadersTypeId
+
 /**
  * @since 1.0.0
  * @category models
  */
-export interface Headers extends ReadonlyRecord.ReadonlyRecord<string> {}
+export type Headers = Brand.Branded<ReadonlyRecord.ReadonlyRecord<string>, HeadersTypeId>
 
 /**
  * @since 1.0.0
  * @category models
  */
-export type Input = Headers | Iterable<readonly [string, string]>
+export type Input = ReadonlyRecord.ReadonlyRecord<string> | Iterable<readonly [string, string]>
 
 /**
  * @since 1.0.0
  * @category constructors
  */
-export const empty: Headers = ReadonlyRecord.empty()
+export const empty: Headers = Object.create(null) as Headers
 
 /**
  * @since 1.0.0
@@ -35,13 +48,19 @@ export const fromInput: (input?: Input) => Headers = (input) => {
     return ReadonlyRecord.fromEntries(ReadonlyArray.map(
       ReadonlyArray.fromIterable(input),
       ([k, v]) => [k.toLowerCase(), v] as const
-    ))
+    )) as Headers
   }
   return ReadonlyRecord.fromEntries(
     Object.entries(input).map(([k, v]) => [k.toLowerCase(), v])
-  )
+  ) as Headers
 }
 
+/**
+ * @since 1.0.0
+ * @category constructors
+ */
+export const unsafeFromRecord = (input: ReadonlyRecord.ReadonlyRecord<string>): Headers => input as Headers
+
 /**
  * @since 1.0.0
  * @category combinators
@@ -96,6 +115,21 @@ export const setAll: {
   ...fromInput(headers)
 }))
 
+/**
+ * @since 1.0.0
+ * @category combinators
+ */
+export const merge: {
+  (headers: Headers): (self: Headers) => Headers
+  (self: Headers, headers: Headers): Headers
+} = dual<
+  (headers: Headers) => (self: Headers) => Headers,
+  (self: Headers, headers: Headers) => Headers
+>(2, (self, headers) => ({
+  ...self,
+  ...headers
+}))
+
 /**
  * @since 1.0.0
  * @category combinators
@@ -106,4 +140,4 @@ export const remove: {
 } = dual<
   (key: string) => (self: Headers) => Headers,
   (self: Headers, key: string) => Headers
->(2, (self, key) => ReadonlyRecord.remove(self, key.toLowerCase()))
+>(2, (self, key) => ReadonlyRecord.remove(self, key.toLowerCase()) as Headers)
diff --git a/packages/platform/src/Http/Platform.ts b/packages/platform/src/Http/Platform.ts
index 4adb6da6..69e5b118 100644
--- a/packages/platform/src/Http/Platform.ts
+++ b/packages/platform/src/Http/Platform.ts
@@ -8,6 +8,7 @@ import type * as FileSystem from "../FileSystem.js"
 import * as internal from "../internal/http/platform.js"
 import type * as Body from "./Body.js"
 import type * as Etag from "./Etag.js"
+import type * as Headers from "./Headers.js"
 import type * as ServerResponse from "./ServerResponse.js"
 
 /**
@@ -54,7 +55,7 @@ export const make: (
       path: string,
       status: number,
       statusText: string | undefined,
-      headers: Record<string, string>,
+      headers: Headers.Headers,
       start: number,
       end: number | undefined,
       contentLength: number
@@ -63,7 +64,7 @@ export const make: (
       file: Body.Body.FileLike,
       status: number,
       statusText: string | undefined,
-      headers: Record<string, string>,
+      headers: Headers.Headers,
       options?: FileSystem.StreamOptions | undefined
     ) => ServerResponse.ServerResponse
   }
diff --git a/packages/platform/src/Http/UrlParams.ts b/packages/platform/src/Http/UrlParams.ts
index 83ca0c95..a3e386a3 100644
--- a/packages/platform/src/Http/UrlParams.ts
+++ b/packages/platform/src/Http/UrlParams.ts
@@ -1,40 +1,38 @@
 /**
  * @since 1.0.0
  */
-import * as Chunk from "effect/Chunk"
 import * as Effect from "effect/Effect"
 import { dual } from "effect/Function"
+import * as ReadonlyArray from "effect/ReadonlyArray"
 
 /**
  * @since 1.0.0
  * @category models
  */
-export interface UrlParams extends Chunk.Chunk<[string, string]> {}
+export interface UrlParams extends ReadonlyArray<readonly [string, string]> {}
 
 /**
  * @since 1.0.0
  * @category models
  */
-export type Input = UrlParams | Readonly<Record<string, string>> | Iterable<readonly [string, string]> | URLSearchParams
+export type Input = Readonly<Record<string, string>> | Iterable<readonly [string, string]> | URLSearchParams
 
 /**
  * @since 1.0.0
  * @category constructors
  */
 export const fromInput = (input: Input): UrlParams => {
-  if (Chunk.isChunk(input)) {
-    return input
-  } else if (Symbol.iterator in input) {
-    return Chunk.fromIterable(input) as UrlParams
+  if (Symbol.iterator in input) {
+    return ReadonlyArray.fromIterable(input)
   }
-  return Chunk.fromIterable(Object.entries(input))
+  return ReadonlyArray.fromIterable(Object.entries(input))
 }
 
 /**
  * @since 1.0.0
  * @category constructors
  */
-export const empty: UrlParams = Chunk.empty()
+export const empty: UrlParams = []
 
 /**
  * @since 1.0.0
@@ -47,8 +45,8 @@ export const set: {
   (key: string, value: string) => (self: UrlParams) => UrlParams,
   (self: UrlParams, key: string, value: string) => UrlParams
 >(3, (self, key, value) =>
-  Chunk.append(
-    Chunk.filter(self, ([k]) => k !== key),
+  ReadonlyArray.append(
+    ReadonlyArray.filter(self, ([k]) => k !== key),
     [key, value]
   ))
 
@@ -64,9 +62,9 @@ export const setAll: {
   (self: UrlParams, input: Input) => UrlParams
 >(2, (self, input) => {
   const toSet = fromInput(input)
-  const keys = Chunk.toReadonlyArray(toSet).map(([k]) => k)
-  return Chunk.appendAll(
-    Chunk.filter(self, ([k]) => keys.includes(k)),
+  const keys = toSet.map(([k]) => k)
+  return ReadonlyArray.appendAll(
+    ReadonlyArray.filter(self, ([k]) => keys.includes(k)),
     toSet
   )
 })
@@ -82,7 +80,7 @@ export const append: {
   (key: string, value: string) => (self: UrlParams) => UrlParams,
   (self: UrlParams, key: string, value: string) => UrlParams
 >(3, (self, key, value) =>
-  Chunk.append(
+  ReadonlyArray.append(
     self,
     [key, value]
   ))
@@ -98,7 +96,7 @@ export const appendAll: {
   (input: Input) => (self: UrlParams) => UrlParams,
   (self: UrlParams, input: Input) => UrlParams
 >(2, (self, input) =>
-  Chunk.appendAll(
+  ReadonlyArray.appendAll(
     self,
     fromInput(input)
   ))
@@ -113,13 +111,13 @@ export const remove: {
 } = dual<
   (key: string) => (self: UrlParams) => UrlParams,
   (self: UrlParams, key: string) => UrlParams
->(2, (self, key) => Chunk.filter(self, ([k]) => k !== key))
+>(2, (self, key) => ReadonlyArray.filter(self, ([k]) => k !== key))
 
 /**
  * @since 1.0.0
  * @category combinators
  */
-export const toString = (self: UrlParams): string => new URLSearchParams(Chunk.toReadonlyArray(self) as any).toString()
+export const toString = (self: UrlParams): string => new URLSearchParams(self as any).toString()
 
 /**
  * @since 1.0.0
@@ -129,7 +127,7 @@ export const makeUrl = <E>(url: string, params: UrlParams, onError: (e: unknown)
   Effect.try({
     try: () => {
       const urlInstance = new URL(url, baseUrl())
-      Chunk.forEach(params, ([key, value]) => {
+      ReadonlyArray.forEach(params, ([key, value]) => {
         if (value !== undefined) {
           urlInstance.searchParams.append(key, value)
         }
diff --git a/packages/platform/src/internal/http/platform.ts b/packages/platform/src/internal/http/platform.ts
index 7f87f5d3..8e1e183c 100644
--- a/packages/platform/src/internal/http/platform.ts
+++ b/packages/platform/src/internal/http/platform.ts
@@ -4,6 +4,7 @@ import { pipe } from "effect/Function"
 import * as FileSystem from "../../FileSystem.js"
 import type * as Body from "../../Http/Body.js"
 import * as Etag from "../../Http/Etag.js"
+import * as Headers from "../../Http/Headers.js"
 import type * as Platform from "../../Http/Platform.js"
 import type * as ServerResponse from "../../Http/ServerResponse.js"
 
@@ -19,7 +20,7 @@ export const make = (impl: {
     path: string,
     status: number,
     statusText: string | undefined,
-    headers: Record<string, string>,
+    headers: Headers.Headers,
     start: number,
     end: number | undefined,
     contentLength: number
@@ -28,7 +29,7 @@ export const make = (impl: {
     file: Body.Body.FileLike,
     status: number,
     statusText: string | undefined,
-    headers: Record<string, string>,
+    headers: Headers.Headers,
     options?: FileSystem.StreamOptions
   ) => ServerResponse.ServerResponse
 }): Effect.Effect<FileSystem.FileSystem | Etag.Generator, never, Platform.Platform> =>
@@ -45,12 +46,9 @@ export const make = (impl: {
           Effect.map(({ etag, info }) => {
             const start = Number(options?.offset ?? 0)
             const end = options?.bytesToRead !== undefined ? start + Number(options.bytesToRead) : undefined
-            const headers: Record<string, string> = {
-              ...(options?.headers ?? {}),
-              etag: Etag.toString(etag)
-            }
+            const headers = Headers.set(options?.headers ?? Headers.empty, "etag", Etag.toString(etag))
             if (info.mtime._tag === "Some") {
-              headers["last-modified"] = info.mtime.value.toUTCString()
+              ;(headers as any)["last-modified"] = info.mtime.value.toUTCString()
             }
             const contentLength = end !== undefined ? end - start : Number(info.size) - start
             return impl.fileResponse(
@@ -67,11 +65,13 @@ export const make = (impl: {
       },
       fileWebResponse(file, options) {
         return Effect.map(etagGen.fromFileWeb(file), (etag) => {
-          const headers: Record<string, string> = {
-            ...(options?.headers ?? {}),
-            etag: Etag.toString(etag),
-            "last-modified": new Date(file.lastModified).toUTCString()
-          }
+          const headers = Headers.merge(
+            options?.headers ?? Headers.empty,
+            Headers.unsafeFromRecord({
+              etag: Etag.toString(etag),
+              "last-modified": new Date(file.lastModified).toUTCString()
+            })
+          )
           return impl.fileWebResponse(
             file,
             options?.status ?? 200,