diff --git a/.changeset/late-terms-taste.md b/.changeset/late-terms-taste.md
new file mode 100644
index 00000000..dd5392be
--- /dev/null
+++ b/.changeset/late-terms-taste.md
@@ -0,0 +1,5 @@
+---
+"counterfact": patch
+---
+
+fix types: $.header should be $.headers (#1160)
diff --git a/docs/usage.md b/docs/usage.md
index 3a29bd70..e1b47e44 100644
--- a/docs/usage.md
+++ b/docs/usage.md
@@ -121,11 +121,11 @@ return $.response[200].header("x-coolness-level", 10).text("This is cool!")`.
 
 ### Request parameters
 
-Most of the time, the server's response depends on input from various parts of the request, which are accessible through `$.path`, `$.query`, `$.header`, and `$.body`. The best way to explain is with an example:
+Most of the time, the server's response depends on input from various parts of the request, which are accessible through `$.path`, `$.query`, `$.headers`, and `$.body`. The best way to explain is with an example:
 
 ```ts
 export const GET: HTTP_GET = ($) => {
-    if ($.header['x-token'] !== 'super-secret') {
+    if ($.headers['x-token'] !== 'super-secret') {
        return $.response[401].text('unauthorized');
     }
 
diff --git a/src/server/types.ts b/src/server/types.ts
index 066ec344..20396880 100644
--- a/src/server/types.ts
+++ b/src/server/types.ts
@@ -259,7 +259,7 @@ interface WideResponseBuilder {
 interface WideOperationArgument {
   body: unknown;
   context: unknown;
-  header: { [key: string]: string };
+  headers: { [key: string]: string };
   path: { [key: string]: string };
   proxy: (url: string) => { proxyUrl: string };
   query: { [key: string]: string };
diff --git a/src/typescript-generator/operation-type-coder.js b/src/typescript-generator/operation-type-coder.js
index ffe581ac..8f3fd984 100644
--- a/src/typescript-generator/operation-type-coder.js
+++ b/src/typescript-generator/operation-type-coder.js
@@ -110,7 +110,7 @@ export class OperationTypeCoder extends TypeCoder {
 
     const pathType = new ParametersTypeCoder(parameters, "path").write(script);
 
-    const headerType = new ParametersTypeCoder(parameters, "header").write(
+    const headersType = new ParametersTypeCoder(parameters, "header").write(
       script,
     );
 
@@ -139,7 +139,7 @@ export class OperationTypeCoder extends TypeCoder {
 
     const proxyType = "(url: string) => COUNTERFACT_RESPONSE";
 
-    return `($: OmitValueWhenNever<{ query: ${queryType}, path: ${pathType}, header: ${headerType}, body: ${bodyType}, context: ${contextTypeImportName}, response: ${responseType}, x: ${xType}, proxy: ${proxyType}, user: ${this.userType()} }>) => ${this.responseTypes(
+    return `($: OmitValueWhenNever<{ query: ${queryType}, path: ${pathType}, headers: ${headersType}, body: ${bodyType}, context: ${contextTypeImportName}, response: ${responseType}, x: ${xType}, proxy: ${proxyType}, user: ${this.userType()} }>) => ${this.responseTypes(
       script,
     )} | { status: 415, contentType: "text/plain", body: string } | COUNTERFACT_RESPONSE | { ALL_REMAINING_HEADERS_ARE_OPTIONAL: COUNTERFACT_RESPONSE }`;
   }
diff --git a/test/typescript-generator/__snapshots__/generate.test.ts.snap b/test/typescript-generator/__snapshots__/generate.test.ts.snap
index 887459c8..9c531892 100644
--- a/test/typescript-generator/__snapshots__/generate.test.ts.snap
+++ b/test/typescript-generator/__snapshots__/generate.test.ts.snap
@@ -30,7 +30,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: Pet;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -78,7 +78,7 @@ export type HTTP_PUT = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: Pet;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -165,7 +165,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: { status?: "available" | "pending" | "sold" };
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -236,7 +236,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: { tags?: Array<string> };
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -317,7 +317,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: { petId: number };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -373,7 +373,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: { name?: number; status?: string };
     path: { petId: number };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -399,7 +399,7 @@ export type HTTP_DELETE = (
   $: OmitValueWhenNever<{
     query: never;
     path: { petId: string };
-    header: { api_key?: string };
+    headers: { api_key?: string };
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -448,7 +448,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: { additionalMetadata?: number };
     path: { petId: number };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -502,7 +502,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -557,7 +557,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: Order;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -625,7 +625,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: { orderId: number };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -681,7 +681,7 @@ export type HTTP_DELETE = (
   $: OmitValueWhenNever<{
     query: never;
     path: { orderId: number };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -739,7 +739,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: User;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -803,7 +803,7 @@ export type HTTP_POST = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: Array<User>;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -873,7 +873,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: { username?: string; password?: string };
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -947,7 +947,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1007,7 +1007,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: { username: string };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1063,7 +1063,7 @@ export type HTTP_PUT = (
   $: OmitValueWhenNever<{
     query: never;
     path: { username: string };
-    header: never;
+    headers: never;
     body: User;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1089,7 +1089,7 @@ export type HTTP_DELETE = (
   $: OmitValueWhenNever<{
     query: never;
     path: { username: string };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1212,7 +1212,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1267,7 +1267,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1322,7 +1322,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1377,7 +1377,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: { name: string };
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
@@ -1436,7 +1436,7 @@ export type HTTP_GET = (
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: Context;
     response: ResponseBuilderFactory<{
diff --git a/test/typescript-generator/__snapshots__/operation-type-coder.test.js.snap b/test/typescript-generator/__snapshots__/operation-type-coder.test.js.snap
index d19be651..9d12a350 100644
--- a/test/typescript-generator/__snapshots__/operation-type-coder.test.js.snap
+++ b/test/typescript-generator/__snapshots__/operation-type-coder.test.js.snap
@@ -5,7 +5,7 @@ exports[`an OperationTypeCoder falls back to root level produces (OpenAPI 2) 1`]
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -40,7 +40,7 @@ exports[`an OperationTypeCoder generates a complex post operation (OpenAPI 2 wit
   $: OmitValueWhenNever<{
     query: { name?: string };
     path: { id?: string };
-    header: { name?: string };
+    headers: { name?: string };
     body: Type;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -103,7 +103,7 @@ exports[`an OperationTypeCoder generates a complex post operation (OpenAPI 2) 1`
   $: OmitValueWhenNever<{
     query: { name?: string };
     path: { id?: string };
-    header: { name?: string };
+    headers: { name?: string };
     body: Type;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -166,7 +166,7 @@ exports[`an OperationTypeCoder generates a complex post operation (OpenAPI 2, co
   $: OmitValueWhenNever<{
     query: { name?: string };
     path: { id?: string };
-    header: { name?: string };
+    headers: { name?: string };
     body: Type;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -229,7 +229,7 @@ exports[`an OperationTypeCoder generates a complex post operation 1`] = `
   $: OmitValueWhenNever<{
     query: { name?: string };
     path: { id?: string };
-    header: { name?: string };
+    headers: { name?: string };
     body: Type;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -292,7 +292,7 @@ exports[`an OperationTypeCoder generates a simple get operation (OpenAPI 2) 1`]
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -327,7 +327,7 @@ exports[`an OperationTypeCoder generates a simple get operation 1`] = `
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: ExternalType;
     response: ResponseBuilderFactory<{
@@ -362,7 +362,7 @@ exports[`an OperationTypeCoder generates an auth object for basic authentication
   $: OmitValueWhenNever<{
     query: never;
     path: never;
-    header: never;
+    headers: never;
     body: never;
     context: ExternalType;
     response: ResponseBuilderFactory<{