diff --git a/ui/src/AppBoot.js b/ui/src/AppBoot.js
new file mode 100644
index 000000000..1a2551afa
--- /dev/null
+++ b/ui/src/AppBoot.js
@@ -0,0 +1,58 @@
+// helpers used to bootstrap App instance and environment for it
+
+import Raven from "raven-js";
+
+const SettingsElement = () => document.getElementById("settings");
+
+const SetupRaven = settingsElement => {
+  if (
+    settingsElement !== null &&
+    settingsElement.dataset.ravenDsn &&
+    settingsElement.dataset.ravenDsn !== "{{ .SentryDSN }}"
+  ) {
+    let version = "unknown";
+    if (
+      settingsElement.dataset.version &&
+      settingsElement.dataset.version !== "{{ .Version }}"
+    ) {
+      version = settingsElement.dataset.version;
+    }
+
+    const ravenClient = new Raven.Client();
+    try {
+      ravenClient
+        .config(settingsElement.dataset.ravenDsn, {
+          release: version
+        })
+        .install();
+    } catch (err) {
+      console.error("Raven config failed: " + err);
+    }
+    return ravenClient;
+  }
+  return null;
+};
+
+const ParseDefaultFilters = settingsElement => {
+  let defaultFilters = [];
+  if (
+    settingsElement !== null &&
+    settingsElement.dataset.defaultFiltersBase64 &&
+    settingsElement.dataset.defaultFiltersBase64 !== "{{ .DefaultFilter }}"
+  ) {
+    // decode from base64 to a string
+    const decoded = Buffer.from(
+      settingsElement.dataset.defaultFiltersBase64,
+      "base64"
+    ).toString("ascii");
+    // parse decoded string as JSON
+    const json = JSON.parse(decoded);
+    // if we got an array then use it as default filters
+    if (Array.isArray(json)) {
+      defaultFilters = json;
+    }
+  }
+  return defaultFilters;
+};
+
+export { SettingsElement, SetupRaven, ParseDefaultFilters };
diff --git a/ui/src/AppBoot.test.js b/ui/src/AppBoot.test.js
new file mode 100644
index 000000000..705301c97
--- /dev/null
+++ b/ui/src/AppBoot.test.js
@@ -0,0 +1,90 @@
+import { SettingsElement, SetupRaven, ParseDefaultFilters } from "./AppBoot";
+
+const MockSettings = (version, ravenDsn, defaultFilters) => {
+  return jest.spyOn(document, "getElementById").mockImplementation(() => {
+    const filtersBase64 = btoa(JSON.stringify(defaultFilters));
+    const settings = document.createElement("span");
+    settings.id = "settings";
+    settings.dataset = {
+      version: version,
+      ravenDsn: ravenDsn,
+      defaultFiltersBase64: filtersBase64
+    };
+    return settings;
+  });
+};
+
+const RavenClient = (ravenDsn, version) => {
+  const settings = document.createElement("span");
+  settings.dataset = { ravenDsn: ravenDsn, version: version };
+  return SetupRaven(settings);
+};
+
+const FiltersSetting = filters => {
+  const settings = document.createElement("span");
+  settings.dataset = { defaultFiltersBase64: btoa(JSON.stringify(filters)) };
+  return ParseDefaultFilters(settings);
+};
+
+describe("SettingsElement()", () => {
+  it("returns null when '#settings' is missing", () => {
+    const settings = SettingsElement();
+    expect(settings).toBeNull();
+  });
+
+  it("returns correct span when '#settings' is present", () => {
+    const spy = MockSettings("ver1", "fakeDSN", []);
+    const settings = SettingsElement();
+    expect(spy).toHaveBeenCalledTimes(1);
+    expect(settings.id).toBe("settings");
+    expect(settings.dataset.version).toBe("ver1");
+    expect(settings.dataset.ravenDsn).toBe("fakeDSN");
+  });
+});
+
+describe("SetupRaven()", () => {
+  it("does nothing when raven DSN is missing", () => {
+    const client = RavenClient("");
+    expect(client).toBeNull();
+  });
+
+  it("configures raven when DSN is present", () => {
+    const client = RavenClient("https://key@example.com/mock");
+    expect(client.isSetup()).toBeTruthy();
+    expect(client._dsn).toBe("https://key@example.com/mock");
+  });
+
+  it("passes release option when version attr is present", () => {
+    const client = RavenClient("https://key@example.com/mock", "ver1");
+    expect(client.isSetup()).toBeTruthy();
+    expect(client._globalOptions.release).toBe("ver1");
+  });
+
+  it("logs an error when invalid DSN is passed to raven", () => {
+    const consoleSpy = jest.spyOn(console, "error");
+    const client = RavenClient("invalidDSN");
+    expect(client.isSetup()).toBeFalsy();
+    expect(consoleSpy).toHaveBeenCalledTimes(1);
+  });
+});
+
+describe("ParseDefaultFilters()", () => {
+  it("returns [] on missing filters attr", () => {
+    const settings = document.createElement("span");
+    settings.dataset = {};
+    expect(ParseDefaultFilters(settings)).toHaveLength(0);
+  });
+
+  it("returns [] on empty filters attr", () => {
+    const settings = document.createElement("span");
+    settings.dataset = { defaultFiltersBase64: "" };
+    expect(ParseDefaultFilters(settings)).toHaveLength(0);
+  });
+
+  it("returns decoded filters", () => {
+    const filters = FiltersSetting(["foo=bar", "bar=~baz"]);
+    expect(filters).toHaveLength(2);
+    expect(filters).toContain("foo=bar");
+    expect(filters).toContain("bar=~baz");
+  });
+});
diff --git a/ui/src/index.js b/ui/src/index.js
index 7643947bc..6786560c4 100644
--- a/ui/src/index.js
+++ b/ui/src/index.js
@@ -1,61 +1,21 @@
 import React from "react";
 import ReactDOM from "react-dom";
 
-import Raven from "raven-js";
-
 import Moment from "react-moment";
 
+import { SettingsElement, SetupRaven, ParseDefaultFilters } from "./AppBoot";
 import { App } from "./App";
 
-let defaultFilters = [];
+const settingsElement = SettingsElement();
 
-// check if we have early settings
-const settings = document.getElementById("settings");
-if (settings !== null) {
-  // sentry setup if sentry dsn is set
-  if (
-    settings.dataset.ravenDsn &&
-    settings.dataset.ravenDsn !== "{{ .SentryDSN }}"
-  ) {
-    let version = "unknown";
-    if (
-      settings.dataset.version &&
-      settings.dataset.version !== "{{ .Version }}"
-    ) {
-      version = settings.dataset.version;
-    }
-
-    try {
-      Raven.config(settings.dataset.ravenDsn, { release: version }).install();
-    } catch (err) {
-      console.error("Raven config failed: " + err);
-    }
-  }
-
-  // default filters, JSON blob encoded with base64
-  if (
-    settings.dataset.defaultFiltersBase64 &&
-    settings.dataset.defaultFiltersBase64 !== "{{ .DefaultFilter }}"
-  ) {
-    // decode from base64 to a string
-    const decoded = Buffer.from(
-      settings.dataset.defaultFiltersBase64,
-      "base64"
-    ).toString("ascii");
-    // parse decoded string as JSON
-    const json = JSON.parse(decoded);
-    // if we got an array then use it as default filters
-    if (Array.isArray(json)) {
-      defaultFilters = json;
-    }
-  }
-}
+SetupRaven(settingsElement);
 
 // global timer for updating timestamps to human readable offsets
 // this needs to be run before any <Moment/> instance
 // https://www.npmjs.com/package/react-moment#pooled-timer
 Moment.startPooledTimer();
 
+const defaultFilters = ParseDefaultFilters(settingsElement);
 ReactDOM.render(
   <App defaultFilters={defaultFilters} />,
   document.getElementById("root")