diff --git a/circleci.go b/circleci.go
index 2ca1688..fe266f3 100644
--- a/circleci.go
+++ b/circleci.go
@@ -120,7 +120,7 @@ func (c *Client) newRequest(method string, path string, v interface{}) (*http.Re
 
 	reqHeaders := make(http.Header)
 	reqHeaders.Set("Circle-Token", c.token)
-	reqHeaders.Set("Accept", "application/vnd.api+json")
+	reqHeaders.Set("Accept", "application/json")
 
 	var body interface{}
 	switch method {
@@ -133,7 +133,7 @@ func (c *Client) newRequest(method string, path string, v interface{}) (*http.Re
 			u.RawQuery = q.Encode()
 		}
 	case "DELETE", "PATCH", "POST", "PUT":
-		reqHeaders.Set("Content-Type", "application/vnd.api+json")
+		reqHeaders.Set("Content-Type", "application/json")
 		body = v
 	}
 
diff --git a/context_test.go b/context_test.go
index c4d4782..20ba834 100644
--- a/context_test.go
+++ b/context_test.go
@@ -15,7 +15,7 @@ func Test_contexts_List(t *testing.T) {
 
 	mux.HandleFunc("/context", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "owner-slug", "org")
 		fmt.Fprint(w, `{"items": [{"id": "1"}], "next_page_token": "1"}`)
@@ -49,7 +49,7 @@ func Test_contexts_Create(t *testing.T) {
 
 	mux.HandleFunc("/context", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"name":"ctx","owner":{"slug":"org","type":"organization"}}`+"\n")
 		fmt.Fprint(w, `{"id": "1"}`)
@@ -84,7 +84,7 @@ func Test_contexts_Get(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/context/%s", contextID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1"}`)
 	})
@@ -112,7 +112,7 @@ func Test_contexts_Delete(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/context/%s", contextID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "DELETE")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -132,7 +132,7 @@ func Test_contexts_ListVariables(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/context/%s", contextID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"variable": "ENVVAR1", "context_id": "ctx1"}], "next_page_token": "1"}`)
 	})
@@ -167,7 +167,7 @@ func Test_contexts_RemoveVariable(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/context/%s/environment-variable/%s", contextID, variableName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "DELETE")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -189,7 +189,7 @@ func Test_contexts_AddOrUpdateVariable(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/context/%s/environment-variable/%s", contextID, variableName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "PUT")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"value":"VAL1"}`+"\n")
 		fmt.Fprint(w, `{"variable": "ENV1", "context_id": "ctx1"}`)
diff --git a/insight_test.go b/insight_test.go
index 2b0984b..01c8b15 100644
--- a/insight_test.go
+++ b/insight_test.go
@@ -18,7 +18,7 @@ func Test_insights_ListSummaryMetricsForWorkflows(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/insights/%s/workflows", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		testQuery(t, r, "all-branches", "true")
@@ -59,7 +59,7 @@ func Test_insights_ListSummaryMetricsForWorkflowJobs(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/insights/%s/workflows/%s/jobs", projectSlug, workflosName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		testQuery(t, r, "all-branches", "true")
@@ -100,7 +100,7 @@ func Test_insights_GetTestMetricsForWorkflows(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/insights/%s/workflows/%s/test-metrics", projectSlug, workflosName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "all-branches", "true")
 		fmt.Fprint(w, `{"average_test_count": 0, "most_failed_tests": [{"failed_runs": 0}]}`)
@@ -137,7 +137,7 @@ func Test_insights_ListWorkflowRuns(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/insights/%s/workflows/%s", projectSlug, workflosName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		testQuery(t, r, "all-branches", "true")
@@ -184,7 +184,7 @@ func Test_insights_ListWorkflowJobRuns(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/insights/%s/workflows/%s/jobs/%s", projectSlug, workflosName, jobName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		testQuery(t, r, "all-branches", "true")
diff --git a/job_test.go b/job_test.go
index 5981dbf..a0e8936 100644
--- a/job_test.go
+++ b/job_test.go
@@ -18,7 +18,7 @@ func Test_jobs_Get(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/job/%s", projectSlug, jobNumber), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"name": "job1"}`)
 	})
@@ -47,7 +47,7 @@ func Test_jobs_Cancel(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/job/%s/cancel", projectSlug, jobNumber), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "success"}`)
 	})
@@ -68,7 +68,7 @@ func Test_jobs_ListArtifacts(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/%s/artifacts", projectSlug, jobNumber), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"path": "path", "node_index": 0, "url": "url"}]}`)
 	})
@@ -103,7 +103,7 @@ func Test_jobs_ListTestMetadata(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/%s/tests", projectSlug, jobNumber), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"message": "message"}]}`)
 	})
diff --git a/pipeline_test.go b/pipeline_test.go
index 446396d..c961808 100644
--- a/pipeline_test.go
+++ b/pipeline_test.go
@@ -15,7 +15,7 @@ func Test_pipelines_List(t *testing.T) {
 
 	mux.HandleFunc("/pipeline/", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "org-slug", "org1")
 		testQuery(t, r, "mine", "true")
@@ -54,7 +54,7 @@ func Test_pipelines_Continue(t *testing.T) {
 
 	mux.HandleFunc("/pipeline/continue", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"continuation-key":"key1","configuration":"cfg1","parameters":{"deploy_prod":true}}`+"\n")
 		fmt.Fprint(w, `{"message": "string"}`)
@@ -81,7 +81,7 @@ func Test_pipelines_Get(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/pipeline/%s", pipelineID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1"}`)
 	})
@@ -109,7 +109,7 @@ func Test_pipelines_GetConfig(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/pipeline/%s/config", pipelineID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"source": "a", "compiled": "b"}`)
 	})
@@ -138,7 +138,7 @@ func Test_pipelines_ListWorkflows(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/pipeline/%s/workflow", pipelineID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		fmt.Fprint(w, `{"items": [{"pipeline_id": "pipeline1", "pipeline_number": 0}], "next_page_token": "2"}`)
diff --git a/project_test.go b/project_test.go
index f68a6b1..a9a8091 100644
--- a/project_test.go
+++ b/project_test.go
@@ -17,7 +17,7 @@ func Test_projects_Get(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"slug": "gh/org1/prj1"}`)
 	})
@@ -46,7 +46,7 @@ func Test_projects_CreateCheckoutKey(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/checkout-key", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"type":"deploy-key"}`+"\n")
 		fmt.Fprint(w, `{"type": "deploy-key", "preferred": true}`)
@@ -79,7 +79,7 @@ func Test_projects_ListCheckoutKeys(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/checkout-key", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"type": "deploy-key"}], "next_page_token": "1"}`)
 	})
@@ -113,7 +113,7 @@ func Test_projects_GetCheckoutKey(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/checkout-key/%s", projectSlug, fingerprint), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"fingerprint": "xx:yy:zz"}`)
 	})
@@ -142,7 +142,7 @@ func Test_projects_DeletetCheckoutKey(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/checkout-key/%s", projectSlug, fingerprint), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "DELETE")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -164,7 +164,7 @@ func Test_projects_CreateVariable(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/envvar", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"name":"ENV1","value":"VAL1"}`+"\n")
 		fmt.Fprint(w, `{"name": "ENV1", "value": "VAL1"}`)
@@ -197,7 +197,7 @@ func Test_projects_ListVariables(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/envvar", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"name": "ENV1"}], "next_page_token": "1"}`)
 	})
@@ -231,7 +231,7 @@ func Test_projects_DeleteVariable(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/envvar/%s", projectSlug, variableName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "DELETE")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -252,7 +252,7 @@ func Test_projects_GetVariable(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/envvar/%s", projectSlug, variableName), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"name": "ENV1", "value": "VAL1"}`)
 	})
@@ -281,7 +281,7 @@ func Test_projects_TriggerPipeline(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/pipeline", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"branch":"main","tag":"v0.1.0","parameters":{"deploy_prod":true}}`+"\n")
 		fmt.Fprint(w, `{"id": "1","state": "created", "number": 0}`)
@@ -319,7 +319,7 @@ func Test_projects_ListPipelines(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/pipeline", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "branch", "main")
 		fmt.Fprint(w, `{"items": [{"id": "1", "trigger": {"type": "explicit"}}], "next_page_token": "1"}`)
@@ -358,7 +358,7 @@ func Test_projects_ListMyPipelines(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/pipeline/mine", projectSlug), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testQuery(t, r, "page-token", "1")
 		fmt.Fprint(w, `{"items": [{"id": "1", "trigger": {"type": "explicit"}}], "next_page_token": "1"}`)
@@ -398,7 +398,7 @@ func Test_projects_GetPipeline(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/project/%s/pipeline/%s", projectSlug, pipelineNumber), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1", "trigger": {"type": "explicit"}}`)
 	})
diff --git a/user_test.go b/user_test.go
index dd17cc1..e4599f6 100644
--- a/user_test.go
+++ b/user_test.go
@@ -15,7 +15,7 @@ func Test_users_Me(t *testing.T) {
 
 	mux.HandleFunc("/me", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1", "login": "login1", "name": "name1"}`)
 	})
@@ -43,7 +43,7 @@ func Test_users_Collaborations(t *testing.T) {
 
 	mux.HandleFunc("/me/collaborations", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `[{"vcs-type": "vcs1", "name": "name1", "avatar_url": "avatar1"}]`)
 	})
@@ -75,7 +75,7 @@ func Test_users_GetUser(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/user/%s", userID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1", "login": "login1", "name": "name1"}`)
 	})
diff --git a/workflow_test.go b/workflow_test.go
index 34ea2f4..417455b 100644
--- a/workflow_test.go
+++ b/workflow_test.go
@@ -17,7 +17,7 @@ func Test_workflows_Get(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/workflow/%s", workflowID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"id": "1"}`)
 	})
@@ -46,7 +46,7 @@ func Test_workflows_ApproveJob(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/workflow/%s/approve/%s", workflowID, jobID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -66,7 +66,7 @@ func Test_workflows_Cancel(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/workflow/%s/cancel", workflowID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"message": "string"}`)
 	})
@@ -86,7 +86,7 @@ func Test_workflows_ListWorkflowJobs(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/workflow/%s/job", workflowID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "GET")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		fmt.Fprint(w, `{"items": [{"id": "1"}], "next_page_token": "1"}`)
 	})
@@ -119,7 +119,7 @@ func Test_workflows_Rerun(t *testing.T) {
 
 	mux.HandleFunc(fmt.Sprintf("/workflow/%s/rerun", workflowID), func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "POST")
-		testHeader(t, r, "Accept", "application/vnd.api+json")
+		testHeader(t, r, "Accept", "application/json")
 		testHeader(t, r, "Circle-Token", client.token)
 		testBody(t, r, `{"jobs":["xxx-yyy-zzz"],"from_failed":true,"sparse_tree":false}`+"\n")
 		fmt.Fprint(w, `{"message": "string"}`)