hey-api · mrlubos · Oct 30, 2025 · Oct 30, 2025 · Oct 30, 2025 · Oct 30, 2025
diff --git a/.changeset/fluffy-suits-care.md b/.changeset/fluffy-suits-care.md
@@ -0,0 +1,5 @@
+---
+"@hey-api/openapi-ts": patch
+---
+
+fix(parser): handle OpenAPI 2.0 body as JSON by default if not explicitly defined
diff --git a/packages/openapi-ts-tests/main/test/__snapshots__/2.0.x/external/types.gen.ts b/packages/openapi-ts-tests/main/test/__snapshots__/2.0.x/external/types.gen.ts
@@ -176,7 +176,10 @@ export type GetExternalModelResponses = {
 export type GetExternalModelResponse = GetExternalModelResponses[keyof GetExternalModelResponses];
 
 export type PostExternalModelData = {
-    body?: never;
+    /**
+     * Request body using external model
+     */
+    body: ExternalSharedExternalSharedModel;
     path?: never;
     query?: never;
     url: '/external-model';
@@ -217,7 +220,10 @@ export type GetExternalUuidResponses = {
 export type GetExternalUuidResponse = GetExternalUuidResponses[keyof GetExternalUuidResponses];
 
 export type PutExternalUuidData = {
-    body?: never;
+    /**
+     * Request body using external UUID
+     */
+    body?: ExternalSharedExternalSharedModelWithUuid;
     path?: never;
     query?: never;
     url: '/external-uuid';
@@ -252,7 +258,10 @@ export type GetExternalNestedResponses = {
 export type GetExternalNestedResponse = GetExternalNestedResponses[keyof GetExternalNestedResponses];
 
 export type PostExternalNestedData = {
-    body?: never;
+    /**
+     * Request body using external nested object
+     */
+    body?: ExternalSharedExternalNested;
     path?: never;
     query?: never;
     url: '/external-nested';
@@ -292,7 +301,15 @@ export type GetExternalMixedResponses = {
 export type GetExternalMixedResponse = GetExternalMixedResponses[keyof GetExternalMixedResponses];
 
 export type PostExternalMixedData = {
-    body?: never;
+    /**
+     * Request body with mixed external properties
+     */
+    body?: {
+        id?: ExternalSharedId;
+        name?: ExternalSharedName;
+        uuid?: ExternalSharedExternalSharedModelWithUuid;
+        deep?: ExternalSharedDeep;
+    };
     path?: never;
     query?: never;
     url: '/external-mixed';
@@ -324,7 +341,7 @@ export type GetExternalArrayResponses = {
 export type GetExternalArrayResponse = GetExternalArrayResponses[keyof GetExternalArrayResponses];
 
 export type PostExternalArrayData = {
-    body?: never;
+    body: Array<ExternalSharedExternalSharedModel>;
     path?: never;
     query?: never;
     url: '/external-array';
@@ -354,7 +371,7 @@ export type GetExternalUnionResponses = {
 };
 
 export type PostExternalUnionData = {
-    body?: never;
+    body: unknown;
     path?: never;
     query?: never;
     url: '/external-union';

diff --git a/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default-class/sdk.gen.ts b/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default-class/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default-class/types.gen.ts b/...ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default-class/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default/sdk.gen.ts b/...openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...enapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default/types.gen.ts b/...enapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@angular/common/default/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...es/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/default/sdk.gen.ts b/...es/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/default/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/.../openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/default/types.gen.ts b/.../openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/default/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...enapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/throwOnError/sdk.gen.ts b/...enapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/throwOnError/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = true>(options:
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = true>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/throwOnError/types.gen.ts b/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@hey-api/sdk/throwOnError/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...ges/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@pinia/colada/fetch/sdk.gen.ts b/...ges/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@pinia/colada/fetch/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...s/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@pinia/colada/fetch/types.gen.ts b/...s/openapi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@pinia/colada/fetch/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...in/test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/axios/sdk.gen.ts b/...in/test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/axios/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/.../test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/axios/types.gen.ts b/.../test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/axios/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...in/test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/fetch/sdk.gen.ts b/...in/test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/fetch/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/.../test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/fetch/types.gen.ts b/.../test/__snapshots__/2.0.x/plugins/@tanstack/angular-query-experimental/fetch/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/axios/sdk.gen.ts b/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/axios/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/axios/types.gen.ts b/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/axios/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/fetch/sdk.gen.ts b/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/fetch/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/fetch/types.gen.ts b/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/react-query/fetch/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/axios/sdk.gen.ts b/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/axios/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/axios/types.gen.ts b/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/axios/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/fetch/sdk.gen.ts b/...api-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/fetch/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/fetch/types.gen.ts b/...i-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/solid-query/fetch/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...pi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/axios/sdk.gen.ts b/...pi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/axios/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };
 

diff --git a/...-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/axios/types.gen.ts b/...-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/axios/types.gen.ts
@@ -600,7 +600,10 @@ export type CallWithParametersData = {
 };
 
 export type CallWithWeirdParameterNamesData = {
-    body?: never;
+    /**
+     * This is the parameter that is sent as request body
+     */
+    body: string;
     headers: {
         /**
          * This is the parameter that goes into the request header

diff --git a/...pi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/fetch/sdk.gen.ts b/...pi-ts-tests/main/test/__snapshots__/2.0.x/plugins/@tanstack/svelte-query/fetch/sdk.gen.ts
@@ -105,7 +105,11 @@ export const callWithParameters = <ThrowOnError extends boolean = false>(options
 export const callWithWeirdParameterNames = <ThrowOnError extends boolean = false>(options: Options<CallWithWeirdParameterNamesData, ThrowOnError>) => {
     return (options.client ?? client).post<unknown, unknown, ThrowOnError>({
         url: '/api/v{api-version}/parameters/{parameter.path.1}/{parameter-path-2}/{PARAMETER-PATH-3}',
-        ...options
+        ...options,
+        headers: {
+            'Content-Type': 'application/json',
+            ...options.headers
+        }
     });
 };