diff --git a/packages/types/src/envelope.ts b/packages/types/src/envelope.ts
index 2a70cea96667..aa7655db9cea 100644
--- a/packages/types/src/envelope.ts
+++ b/packages/types/src/envelope.ts
@@ -18,12 +18,12 @@ export type BaseEnvelopeItemHeaders = {
   length?: number;
 };
 
-export type BaseEnvelopeItem<IH extends BaseEnvelopeItemHeaders, P extends unknown> = [IH, P]; // P is for payload
+type BaseEnvelopeItem<IH extends BaseEnvelopeItemHeaders, P extends unknown> = [IH, P]; // P is for payload
 
-export type BaseEnvelope<
-  EH extends BaseEnvelopeHeaders,
-  I extends BaseEnvelopeItem<BaseEnvelopeItemHeaders, unknown>,
-> = [EH, I[]];
+type BaseEnvelope<EH extends BaseEnvelopeHeaders, I extends BaseEnvelopeItem<BaseEnvelopeItemHeaders, unknown>> = [
+  EH,
+  I[],
+];
 
 type EventItemHeaders = { type: 'event' | 'transaction' };
 type AttachmentItemHeaders = { type: 'attachment'; filename: string };
diff --git a/packages/types/src/index.ts b/packages/types/src/index.ts
index 996f53c4c685..13651b7cd78e 100644
--- a/packages/types/src/index.ts
+++ b/packages/types/src/index.ts
@@ -6,9 +6,7 @@ export { DsnComponents, DsnLike, DsnProtocol } from './dsn';
 export { DebugImage, DebugImageType, DebugMeta } from './debugMeta';
 export {
   AttachmentItem,
-  BaseEnvelope,
   BaseEnvelopeHeaders,
-  BaseEnvelopeItem,
   BaseEnvelopeItemHeaders,
   ClientReportEnvelope,
   ClientReportItem,
diff --git a/packages/utils/src/envelope.ts b/packages/utils/src/envelope.ts
new file mode 100644
index 000000000000..7552bd339784
--- /dev/null
+++ b/packages/utils/src/envelope.ts
@@ -0,0 +1,38 @@
+import { Envelope } from '@sentry/types';
+
+/**
+ * Creates an envelope.
+ * Make sure to always explicitly provide the generic to this function
+ * so that the envelope types resolve correctly.
+ */
+export function createEnvelope<E extends Envelope>(headers: E[0], items: E[1] = []): E {
+  return [headers, items] as E;
+}
+
+/**
+ * Add an item to an envelope.
+ * Make sure to always explicitly provide the generic to this function
+ * so that the envelope types resolve correctly.
+ */
+export function addItemToEnvelope<E extends Envelope>(envelope: E, newItem: E[1][number]): E {
+  const [headers, items] = envelope;
+  return [headers, [...items, newItem]] as E;
+}
+
+/**
+ * Serializes an envelope into a string.
+ */
+export function serializeEnvelope(envelope: Envelope): string {
+  const [headers, items] = envelope;
+  const serializedHeaders = JSON.stringify(headers);
+
+  // Have to cast items to any here since Envelope is a union type
+  // Fixed in Typescript 4.2
+  // TODO: Remove any[] cast when we upgrade to TS 4.2
+  // https://github.com/microsoft/TypeScript/issues/36390
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  return (items as any[]).reduce((acc, item: typeof items[number]) => {
+    const [itemHeaders, payload] = item;
+    return `${acc}\n${JSON.stringify(itemHeaders)}\n${JSON.stringify(payload)}`;
+  }, serializedHeaders);
+}
diff --git a/packages/utils/src/index.ts b/packages/utils/src/index.ts
index 900e50653037..511d8a1315ca 100644
--- a/packages/utils/src/index.ts
+++ b/packages/utils/src/index.ts
@@ -21,3 +21,4 @@ export * from './supports';
 export * from './syncpromise';
 export * from './time';
 export * from './env';
+export * from './envelope';
diff --git a/packages/utils/test/envelope.test.ts b/packages/utils/test/envelope.test.ts
new file mode 100644
index 000000000000..64cdbe5e39ca
--- /dev/null
+++ b/packages/utils/test/envelope.test.ts
@@ -0,0 +1,47 @@
+import { EventEnvelope } from '@sentry/types';
+
+import { addItemToEnvelope, createEnvelope, serializeEnvelope } from '../src/envelope';
+import { parseEnvelope } from './testutils';
+
+describe('envelope', () => {
+  describe('createEnvelope()', () => {
+    const testTable: Array<[string, Parameters<typeof createEnvelope>[0], Parameters<typeof createEnvelope>[1]]> = [
+      ['creates an empty envelope', {}, []],
+      ['creates an envelope with a header but no items', { dsn: 'https://public@example.com/1', sdk: {} }, []],
+    ];
+    it.each(testTable)('%s', (_: string, headers, items) => {
+      const env = createEnvelope(headers, items);
+      expect(env).toHaveLength(2);
+      expect(env[0]).toStrictEqual(headers);
+      expect(env[1]).toStrictEqual(items);
+    });
+  });
+
+  describe('serializeEnvelope()', () => {
+    it('serializes an envelope', () => {
+      const env = createEnvelope<EventEnvelope>({ event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2', sent_at: '123' }, []);
+      expect(serializeEnvelope(env)).toMatchInlineSnapshot(
+        `"{\\"event_id\\":\\"aa3ff046696b4bc6b609ce6d28fde9e2\\",\\"sent_at\\":\\"123\\"}"`,
+      );
+    });
+  });
+
+  describe('addItemToEnvelope()', () => {
+    it('adds an item to an envelope', () => {
+      const env = createEnvelope<EventEnvelope>({ event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2', sent_at: '123' }, []);
+      const parsedEnvelope = parseEnvelope(serializeEnvelope(env));
+      expect(parsedEnvelope).toHaveLength(1);
+      expect(parsedEnvelope[0]).toEqual({ event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2', sent_at: '123' });
+
+      const newEnv = addItemToEnvelope<EventEnvelope>(env, [
+        { type: 'event' },
+        { event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2' },
+      ]);
+      const parsedNewEnvelope = parseEnvelope(serializeEnvelope(newEnv));
+      expect(parsedNewEnvelope).toHaveLength(3);
+      expect(parsedNewEnvelope[0]).toEqual({ event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2', sent_at: '123' });
+      expect(parsedNewEnvelope[1]).toEqual({ type: 'event' });
+      expect(parsedNewEnvelope[2]).toEqual({ event_id: 'aa3ff046696b4bc6b609ce6d28fde9e2' });
+    });
+  });
+});
diff --git a/packages/utils/test/testutils.ts b/packages/utils/test/testutils.ts
index 6130ee7ca365..aa3c5485eec1 100644
--- a/packages/utils/test/testutils.ts
+++ b/packages/utils/test/testutils.ts
@@ -11,3 +11,7 @@ export const testOnlyIfNodeVersionAtLeast = (minVersion: number): jest.It => {
 
   return it;
 };
+
+export function parseEnvelope(env: string): Array<Record<any, any>> {
+  return env.split('\n').map(e => JSON.parse(e));
+}