diff --git a/packages/core/config.d.ts b/packages/core/config.d.ts
new file mode 100644
index 0000000000..cee871526c
--- /dev/null
+++ b/packages/core/config.d.ts
@@ -0,0 +1,115 @@
+export interface Schema {
+  apiKey: {
+    defaultValue: () => null
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  appVersion: {
+    defaultValue: () => undefined
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  appType: {
+    defaultValue: () => undefined
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  autoDetectErrors: {
+    defaultValue: () => true
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  enabledErrorTypes: {
+    defaultValue: () => { unhandledExceptions: boolean, unhandledRejections: boolean }
+    message: string
+    allowPartialObject: boolean
+    validate: (value: unknown) => boolean
+  }
+  onError: {
+    defaultValue: () => []
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  onSession: {
+    defaultValue: () => []
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  onBreadcrumb: {
+    defaultValue: () => []
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  endpoints: {
+    defaultValue: (endpoints: { notify: string, sessions: string } | undefined) => { notify: string | null, sessions: string | null }
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  autoTrackSessions: {
+    defaultValue: () => boolean
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  enabledReleaseStages: {
+    defaultValue: () => null
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  releaseStage: {
+    defaultValue: () => 'production'
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  maxBreadcrumbs: {
+    defaultValue: () => 25
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  enabledBreadcrumbTypes: {
+    defaultValue: () => ['navigation', 'request', 'process', 'log', 'user', 'state', 'error', 'manual']
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  context: {
+    defaultValue: () => undefined
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  user: {
+    defaultValue: () => {}
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  metadata: {
+    defaultValue: () => {}
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  logger: {
+    defaultValue: () => undefined
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  redactedKeys: {
+    defaultValue: () => ['password']
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  plugins: {
+    defaultValue: () => []
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  featureFlags: {
+    defaultValue: () => []
+    message: string
+    validate: (value: unknown) => boolean
+  }
+  reportUnhandledPromiseRejectionsAsHandled: {
+    defaultValue: () => false
+    message: string
+    validate: (value: unknown) => boolean
+  }
+}
+
+export const schema: Schema
diff --git a/packages/plugin-interaction-breadcrumbs/src/interaction-breadcrumbs.ts b/packages/plugin-interaction-breadcrumbs/src/interaction-breadcrumbs.ts
index ba1b65c961..d910565175 100644
--- a/packages/plugin-interaction-breadcrumbs/src/interaction-breadcrumbs.ts
+++ b/packages/plugin-interaction-breadcrumbs/src/interaction-breadcrumbs.ts
@@ -4,10 +4,10 @@ import type ClientWithInternals from 'packages/core/client'
 /*
  * Leaves breadcrumbs when the user interacts with the DOM
  */
-export default (win = window): Plugin<ClientWithInternals> => ({
+export default (win = window): Plugin => ({
   load: (client) => {
     if (!('addEventListener' in win)) return
-    if (!client._isBreadcrumbTypeEnabled('user')) return
+    if (!(client as ClientWithInternals)._isBreadcrumbTypeEnabled('user')) return
 
     win.addEventListener('click', (event) => {
       let targetText, targetSelector
@@ -16,8 +16,8 @@ export default (win = window): Plugin<ClientWithInternals> => ({
         targetSelector = getNodeSelector(event.target, win)
       } catch (e) {
         targetText = '[hidden]'
-        targetSelector = '[hidden]'
-        client._logger.error('Cross domain error when tracking click event. See docs: https://tinyurl.com/yy3rn63z')
+        targetSelector = '[hidden]';
+        (client as ClientWithInternals)._logger.error('Cross domain error when tracking click event. See docs: https://tinyurl.com/yy3rn63z')
       }
       client.leaveBreadcrumb('UI click', { targetText, targetSelector }, 'user')
     }, true)