diff --git a/ui/package.json b/ui/package.json
index a78b13e76..f64c53f1e 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -19,6 +19,7 @@
     "favico.js": "0.3.10",
     "fontfaceobserver": "2.1.0",
     "lodash.debounce": "4.0.8",
+    "lodash.merge": "4.6.2",
     "lodash.throttle": "4.1.1",
     "lodash.uniqueid": "4.0.1",
     "mobx": "5.13.0",
diff --git a/ui/src/Common/Fetch.js b/ui/src/Common/Fetch.js
new file mode 100644
index 000000000..15a1e2e11
--- /dev/null
+++ b/ui/src/Common/Fetch.js
@@ -0,0 +1,6 @@
+import merge from "lodash.merge";
+
+const FetchWithCredentials = async (uri, options) =>
+  await fetch(uri, merge({}, { credentials: "include" }, options));
+
+export { FetchWithCredentials };
diff --git a/ui/src/Common/Fetch.test.js b/ui/src/Common/Fetch.test.js
new file mode 100644
index 000000000..14483d44c
--- /dev/null
+++ b/ui/src/Common/Fetch.test.js
@@ -0,0 +1,40 @@
+import { FetchWithCredentials } from "./Fetch";
+
+beforeEach(() => {
+  fetch.resetMocks();
+});
+
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
+describe("FetchWithCredentials", () => {
+  it("fetch passes '{credentials: include}' to all requests", async () => {
+    const request = FetchWithCredentials("http://example.com", {});
+    await expect(request).resolves.toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith("http://example.com", {
+      credentials: "include"
+    });
+  });
+
+  it("custom keys are merged with defaults", async () => {
+    const request = FetchWithCredentials("http://example.com", {
+      foo: "bar"
+    });
+    await expect(request).resolves.toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith("http://example.com", {
+      credentials: "include",
+      foo: "bar"
+    });
+  });
+
+  it("custom credentials are used when passed", async () => {
+    const request = FetchWithCredentials("http://example.com", {
+      credentials: "none"
+    });
+    await expect(request).resolves.toBeUndefined();
+    expect(fetch).toHaveBeenCalledWith("http://example.com", {
+      credentials: "none"
+    });
+  });
+});
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.js
index 055dbbc58..d22aa16e8 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.js
@@ -15,6 +15,7 @@ import { faCircleNotch } from "@fortawesome/free-solid-svg-icons/faCircleNotch";
 import { APIAlertmanagerUpstream } from "Models/API";
 import { AlertStore, FormatBackendURI, FormatAlertsQ } from "Stores/AlertStore";
 import { FormatQuery, QueryOperators, StaticLabels } from "Common/Query";
+import { FetchWithCredentials } from "Common/Fetch";
 import { Modal } from "Components/Modal";
 import {
   LabelSetList,
@@ -136,7 +137,7 @@ const DeleteSilenceModalContent = observer(
           FormatQuery(StaticLabels.SilenceID, QueryOperators.Equal, silenceID)
         ]);
 
-      this.previewState.fetch = fetch(alertsURI, { credentials: "include" })
+      this.previewState.fetch = FetchWithCredentials(alertsURI, {})
         .then(result => result.json())
         .then(result => {
           this.previewState.groupsToUniqueLabels(Object.values(result.groups));
@@ -165,9 +166,9 @@ const DeleteSilenceModalContent = observer(
         ? `${alertmanager.publicURI}/api/v2/silence/${silenceID}`
         : `${alertmanager.publicURI}/api/v1/silence/${silenceID}`;
 
-      this.deleteState.fetch = fetch(uri, {
+      this.deleteState.fetch = FetchWithCredentials(uri, {
         method: "DELETE",
-        credentials: "include"
+        headers: alertmanager.headers
       })
         .then(result => {
           if (isOpenAPI) {
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.test.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.test.js
index 7704ff8b2..f74f47a93 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.test.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/DeleteSilence.test.js
@@ -122,7 +122,7 @@ describe("<DeleteSilenceModalContent />", () => {
     expect(tree.find("ErrorMessage")).toHaveLength(1);
   });
 
-  it("[v1] sends a DELETE request after clicking 'Confirm' button ", async () => {
+  it("[v1] sends a DELETE request after clicking 'Confirm' button", async () => {
     await VerifyResponse({ status: "success" });
     expect(fetch.mock.calls[1][0]).toBe(
       "http://am.example.com/api/v1/silence/123456789"
@@ -130,7 +130,7 @@ describe("<DeleteSilenceModalContent />", () => {
     expect(fetch.mock.calls[1][1]).toMatchObject({ method: "DELETE" });
   });
 
-  it("[v2] sends a DELETE request after clicking 'Confirm' button ", async () => {
+  it("[v2] sends a DELETE request after clicking 'Confirm' button", async () => {
     alertmanager.version = "0.16.2";
     await VerifyResponse({ status: "success" });
     expect(fetch.mock.calls[1][0]).toBe(
@@ -139,6 +139,33 @@ describe("<DeleteSilenceModalContent />", () => {
     expect(fetch.mock.calls[1][1]).toMatchObject({ method: "DELETE" });
   });
 
+  it("[v1] sends headers from alertmanager config", async () => {
+    alertmanager.headers = { Authorization: "Basic ***" };
+    await VerifyResponse({ status: "success" });
+    expect(fetch.mock.calls[1][0]).toBe(
+      "http://am.example.com/api/v1/silence/123456789"
+    );
+    expect(fetch.mock.calls[1][1]).toMatchObject({
+      credentials: "include",
+      method: "DELETE",
+      headers: { Authorization: "Basic ***" }
+    });
+  });
+
+  it("[v1] sends headers from alertmanager config", async () => {
+    alertmanager.headers = { Authorization: "Basic ***" };
+    alertmanager.version = "0.16.2";
+    await VerifyResponse({ status: "success" });
+    expect(fetch.mock.calls[1][0]).toBe(
+      "http://am.example.com/api/v2/silence/123456789"
+    );
+    expect(fetch.mock.calls[1][1]).toMatchObject({
+      credentials: "include",
+      method: "DELETE",
+      headers: { Authorization: "Basic ***" }
+    });
+  });
+
   it("'Confirm' button is no-op after successful DELETE", async () => {
     const tree = await VerifyResponse({ status: "success" });
     expect(fetch.mock.calls[1][0]).toBe(
diff --git a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
index 1270712d6..51630994e 100644
--- a/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
+++ b/ui/src/Components/Grid/AlertGrid/AlertGroup/Silence/index.test.js
@@ -67,6 +67,7 @@ beforeEach(() => {
         cluster: "default",
         uri: "file:///mock",
         publicURI: "http://example.com",
+        headers: {},
         error: "",
         version: "0.15.0",
         clusterMembers: ["default"]
@@ -203,6 +204,7 @@ describe("<Silence />", () => {
       cluster: "default",
       uri: "file:///mock",
       publicURI: "http://example.com",
+      headers: {},
       error: "",
       version: "0.15.0",
       clusterMembers: ["default"]
diff --git a/ui/src/Components/MainModal/Configuration/SortLabelName.js b/ui/src/Components/MainModal/Configuration/SortLabelName.js
index 02c44cdf4..096b3f6aa 100644
--- a/ui/src/Components/MainModal/Configuration/SortLabelName.js
+++ b/ui/src/Components/MainModal/Configuration/SortLabelName.js
@@ -7,6 +7,7 @@ import { observer } from "mobx-react";
 import Creatable from "react-select/creatable";
 
 import { StaticLabels } from "Common/Query";
+import { FetchWithCredentials } from "Common/Fetch";
 import { FormatBackendURI } from "Stores/AlertStore";
 import { Settings } from "Stores/Settings";
 import { ReactSelectStyles } from "Components/MultiSelect";
@@ -33,9 +34,10 @@ const SortLabelName = observer(
     });
 
     populateNameSuggestions = action(() => {
-      this.nameSuggestionsFetch = fetch(FormatBackendURI(`labelNames.json`), {
-        credentials: "include"
-      })
+      this.nameSuggestionsFetch = FetchWithCredentials(
+        FormatBackendURI(`labelNames.json`),
+        {}
+      )
         .then(
           result => result.json(),
           err => {
diff --git a/ui/src/Components/NavBar/FilterInput/index.js b/ui/src/Components/NavBar/FilterInput/index.js
index 7b285880e..0dc7b5329 100644
--- a/ui/src/Components/NavBar/FilterInput/index.js
+++ b/ui/src/Components/NavBar/FilterInput/index.js
@@ -15,6 +15,7 @@ import { faSearch } from "@fortawesome/free-solid-svg-icons/faSearch";
 import { AlertStore, FormatBackendURI } from "Stores/AlertStore";
 import { Settings } from "Stores/Settings";
 import { IsMobile } from "Common/Device";
+import { FetchWithCredentials } from "Common/Fetch";
 import { FilterInputLabel } from "Components/Labels/FilterInputLabel";
 import { AutosuggestTheme } from "./Constants";
 import { History } from "./History";
@@ -72,9 +73,9 @@ const FilterInput = observer(
     onSuggestionsFetchRequested = debounce(
       action(({ value }) => {
         if (value !== "") {
-          this.inputStore.suggestionsFetch = fetch(
+          this.inputStore.suggestionsFetch = FetchWithCredentials(
             FormatBackendURI(`autocomplete.json?term=${value}`),
-            { credentials: "include" }
+            {}
           )
             .then(
               result => result.json(),
diff --git a/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js b/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
index 1313dd7ec..cd8b4b442 100644
--- a/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
+++ b/ui/src/Components/SilenceModal/AlertManagerInput/index.test.js
@@ -22,6 +22,7 @@ beforeEach(() => {
       name: "am1",
       uri: "http://am1.example.com",
       publicURI: "http://am1.example.com",
+      headers: {},
       error: "",
       version: "0.15.0",
       cluster: "ha",
@@ -31,6 +32,7 @@ beforeEach(() => {
       name: "am2",
       uri: "http://am2.example.com",
       publicURI: "http://am2.example.com",
+      headers: {},
       error: "",
       version: "0.15.0",
       cluster: "ha",
@@ -40,6 +42,7 @@ beforeEach(() => {
       name: "am3",
       uri: "http://am3.example.com",
       publicURI: "http://am3.example.com",
+      headers: {},
       error: "",
       version: "0.15.0",
       cluster: "am3",
diff --git a/ui/src/Components/SilenceModal/SilenceMatch/LabelNameInput.js b/ui/src/Components/SilenceModal/SilenceMatch/LabelNameInput.js
index 4a3176af8..8fc6c6a9e 100644
--- a/ui/src/Components/SilenceModal/SilenceMatch/LabelNameInput.js
+++ b/ui/src/Components/SilenceModal/SilenceMatch/LabelNameInput.js
@@ -8,6 +8,7 @@ import { SilenceFormMatcher } from "Models/SilenceForm";
 import { MultiSelect } from "Components/MultiSelect";
 import { ValidationError } from "Components/MultiSelect/ValidationError";
 import { FormatBackendURI } from "Stores/AlertStore";
+import { FetchWithCredentials } from "Common/Fetch";
 
 const LabelNameInput = observer(
   class LabelNameInput extends MultiSelect {
@@ -19,9 +20,10 @@ const LabelNameInput = observer(
     populateNameSuggestions = action(() => {
       const { matcher } = this.props;
 
-      this.nameSuggestionsFetch = fetch(FormatBackendURI(`labelNames.json`), {
-        credentials: "include"
-      })
+      this.nameSuggestionsFetch = FetchWithCredentials(
+        FormatBackendURI(`labelNames.json`),
+        {}
+      )
         .then(
           result => result.json(),
           err => {
@@ -43,11 +45,9 @@ const LabelNameInput = observer(
     populateValueSuggestions = action(() => {
       const { matcher } = this.props;
 
-      this.valueSuggestionsFetch = fetch(
+      this.valueSuggestionsFetch = FetchWithCredentials(
         FormatBackendURI(`labelValues.json?name=${matcher.name}`),
-        {
-          credentials: "include"
-        }
+        {}
       )
         .then(
           result => result.json(),
diff --git a/ui/src/Components/SilenceModal/SilenceMatch/MatchCounter.js b/ui/src/Components/SilenceModal/SilenceMatch/MatchCounter.js
index c68ef230d..8f9d19bc5 100644
--- a/ui/src/Components/SilenceModal/SilenceMatch/MatchCounter.js
+++ b/ui/src/Components/SilenceModal/SilenceMatch/MatchCounter.js
@@ -14,6 +14,7 @@ import { FormatBackendURI, FormatAlertsQ } from "Stores/AlertStore";
 import { SilenceFormStore } from "Stores/SilenceFormStore";
 import { SilenceFormMatcher } from "Models/SilenceForm";
 import { TooltipWrapper } from "Components/TooltipWrapper";
+import { FetchWithCredentials } from "Common/Fetch";
 import { MatcherToFilter, AlertManagersToFilter } from "../Matchers";
 
 const MatchCounter = observer(
@@ -54,7 +55,7 @@ const MatchCounter = observer(
       const alertsURI =
         FormatBackendURI("alerts.json?") + FormatAlertsQ(filters);
 
-      this.matchedAlerts.fetch = fetch(alertsURI, { credentials: "include" })
+      this.matchedAlerts.fetch = FetchWithCredentials(alertsURI, {})
         .then(result => {
           return result.json();
         })
diff --git a/ui/src/Components/SilenceModal/SilencePreview/index.js b/ui/src/Components/SilenceModal/SilencePreview/index.js
index 41d3c8d2d..2701169e2 100644
--- a/ui/src/Components/SilenceModal/SilencePreview/index.js
+++ b/ui/src/Components/SilenceModal/SilencePreview/index.js
@@ -15,6 +15,7 @@ import {
   LabelSetList,
   GroupListToUniqueLabelsList
 } from "Components/LabelSetList";
+import { FetchWithCredentials } from "Common/Fetch";
 import { MatcherToFilter, AlertManagersToFilter } from "../Matchers";
 
 const FetchError = ({ message }) => (
@@ -67,7 +68,7 @@ const SilencePreview = observer(
       const alertsURI =
         FormatBackendURI("alerts.json?") + FormatAlertsQ(filters);
 
-      this.matchedAlerts.fetch = fetch(alertsURI, { credentials: "include" })
+      this.matchedAlerts.fetch = FetchWithCredentials(alertsURI, {})
         .then(result => {
           return result.json();
         })
diff --git a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
index 45c322ae7..d16ed4a6e 100644
--- a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
+++ b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.js
@@ -13,6 +13,7 @@ import { faExclamationCircle } from "@fortawesome/free-solid-svg-icons/faExclama
 
 import { APISilenceMatcher } from "Models/API";
 import { AlertStore } from "Stores/AlertStore";
+import { FetchWithCredentials } from "Common/Fetch";
 
 const SubmitState = Object.freeze({
   InProgress: "InProgress",
@@ -108,13 +109,13 @@ const SilenceSubmitProgress = observer(
         ? `${am.publicURI}/api/v2/silences`
         : `${am.publicURI}/api/v1/silences`;
 
-      this.submitState.fetch = fetch(uri, {
+      this.submitState.fetch = FetchWithCredentials(uri, {
         method: "POST",
         body: JSON.stringify(payload),
         headers: {
-          "Content-Type": "application/json"
-        },
-        credentials: "include"
+          "Content-Type": "application/json",
+          ...am.headers
+        }
       })
         .then(result => {
           if (isOpenAPI) {
diff --git a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
index d04bab3cb..73d7852fb 100644
--- a/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
+++ b/ui/src/Components/SilenceModal/SilenceSubmit/SilenceSubmitProgress.test.js
@@ -15,6 +15,7 @@ beforeEach(() => {
         name: "mockAlertmanager",
         uri: "file:///mock",
         publicURI: "http://example.com",
+        headers: { foo: "bar" },
         error: "",
         version: "0.15.0",
         cluster: "mockAlertmanager",
@@ -68,7 +69,7 @@ describe("<SilenceSubmitProgress />", () => {
     const payload = fetch.mock.calls[0][1];
     expect(payload).toMatchObject({
       method: "POST",
-      headers: { "Content-Type": "application/json" },
+      headers: { "Content-Type": "application/json", foo: "bar" },
       body: JSON.stringify({
         matchers: [],
         startsAt: "now",
@@ -93,6 +94,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am1",
           uri: "file:///mock",
           publicURI: "http://am1.example.com",
+          headers: {},
           error: "",
           version: "0.15.0",
           cluster: "ha",
@@ -102,6 +104,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am2",
           uri: "file:///mock",
           publicURI: "http://am2.example.com",
+          headers: {},
           error: "",
           version: "0.15.0",
           cluster: "ha",
@@ -147,6 +150,7 @@ describe("<SilenceSubmitProgress />", () => {
           name: "am1",
           uri: "file:///mock",
           publicURI: "http://am1.example.com",
+          headers: {},
           error: "",
           version: "0.15.0",
           cluster: "ha",
diff --git a/ui/src/Models/API.js b/ui/src/Models/API.js
index 46a452ef7..61710615f 100644
--- a/ui/src/Models/API.js
+++ b/ui/src/Models/API.js
@@ -70,6 +70,7 @@ const APIAlertmanagerUpstream = PropTypes.exact({
   cluster: PropTypes.string.isRequired,
   uri: PropTypes.string.isRequired,
   publicURI: PropTypes.string.isRequired,
+  headers: PropTypes.object.isRequired,
   error: PropTypes.string.isRequired,
   version: PropTypes.string.isRequired,
   clusterMembers: PropTypes.arrayOf(PropTypes.string).isRequired
diff --git a/ui/src/Stores/AlertStore.js b/ui/src/Stores/AlertStore.js
index e6025abb5..64ecc7935 100644
--- a/ui/src/Stores/AlertStore.js
+++ b/ui/src/Stores/AlertStore.js
@@ -6,6 +6,8 @@ import equal from "fast-deep-equal";
 
 import qs from "qs";
 
+import { FetchWithCredentials } from "Common/Fetch";
+
 const QueryStringEncodeOptions = {
   encodeValuesOnly: true, // don't encode q[]
   indices: false // go-gin doesn't support parsing q[0]=foo&q[1]=bar
@@ -247,7 +249,7 @@ class AlertStore {
         `alerts.json?sortOrder=${sortOrder}&sortLabel=${sortLabel}&sortReverse=${sortReverse}&`
       ) + FormatAPIFilterQuery(this.filters.values.map(f => f.raw));
 
-    return fetch(alertsURI, { credentials: "include" })
+    return FetchWithCredentials(alertsURI, {})
       .then(result => {
         this.status.setProcessing();
         return result.json();
diff --git a/ui/src/__mocks__/Alerts.js b/ui/src/__mocks__/Alerts.js
index e0059eebf..edaf24c93 100644
--- a/ui/src/__mocks__/Alerts.js
+++ b/ui/src/__mocks__/Alerts.js
@@ -71,6 +71,9 @@ const MockAlertmanager = () => ({
   cluster: "default",
   uri: "http://localhost",
   publicURI: "http://am.example.com",
+  headers: {
+    Authorization: "Basic foo bar"
+  },
   error: "",
   version: "0.15.0",
   clusterMembers: ["default"]