diff --git a/.eslintrc.json b/.eslintrc.json
--- a/.eslintrc.json
+++ b/.eslintrc.json
@@ -1,7 +1,8 @@
 {
   "root": true,
   "env": {
-    "es6": true
+    "es6": true,
+    "es2020": true
   },
   "extends": [
     "eslint:recommended",
diff --git a/lib/permissions/minimally-encoded-thread-permissions.js b/lib/permissions/minimally-encoded-thread-permissions.js
new file mode 100644
--- /dev/null
+++ b/lib/permissions/minimally-encoded-thread-permissions.js
@@ -0,0 +1,79 @@
+// @flow
+
+import invariant from 'invariant';
+
+import type {
+  ThreadPermission,
+  ThreadPermissionsInfo,
+} from '../types/thread-permission-types.js';
+import { entries } from '../utils/objects.js';
+
+const minimallyEncodedThreadPermissions = Object.freeze({
+  // TODO (atul): Update flow to `194.0.0` for bigint support
+  // $FlowIssue bigint-unsupported
+  know_of: BigInt(1) << BigInt(0),
+  membership: BigInt(1) << BigInt(1), // DEPRECATED
+  visible: BigInt(1) << BigInt(2),
+  voiced: BigInt(1) << BigInt(3),
+  edit_entries: BigInt(1) << BigInt(4),
+  edit_thread: BigInt(1) << BigInt(5), // EDIT_THREAD_NAME
+  edit_thread_description: BigInt(1) << BigInt(6),
+  edit_thread_color: BigInt(1) << BigInt(7),
+  delete_thread: BigInt(1) << BigInt(8),
+  create_subthreads: BigInt(1) << BigInt(9), // CREATE_SUBCHANNELS
+  create_sidebars: BigInt(1) << BigInt(10),
+  join_thread: BigInt(1) << BigInt(11),
+  edit_permissions: BigInt(1) << BigInt(12),
+  add_members: BigInt(1) << BigInt(13),
+  remove_members: BigInt(1) << BigInt(14),
+  change_role: BigInt(1) << BigInt(15),
+  leave_thread: BigInt(1) << BigInt(16),
+  react_to_message: BigInt(1) << BigInt(17),
+  edit_message: BigInt(1) << BigInt(18),
+  edit_thread_avatar: BigInt(1) << BigInt(19),
+  manage_pins: BigInt(1) << BigInt(20),
+  manage_invite_links: BigInt(1) << BigInt(21),
+});
+
+// TODO (atul): Update flow to `194.0.0` for bigint support
+// $FlowIssue bigint-unsupported
+const permissionsToBitmask = (permissions: ThreadPermissionsInfo): bigint => {
+  let bitmask = BigInt(0);
+  for (const [key, permission] of entries(permissions)) {
+    if (permission.value && key in minimallyEncodedThreadPermissions) {
+      invariant(
+        // TODO (atul): Update flow to `194.0.0` for bigint support
+        // $FlowIssue illegal-typeof
+        typeof minimallyEncodedThreadPermissions[key] === 'bigint',
+        'must be bigint',
+      );
+      bitmask |= minimallyEncodedThreadPermissions[key];
+    }
+  }
+  return bitmask;
+};
+
+const hasPermission = (
+  // TODO (atul): Update flow to `194.0.0` for bigint support
+  // $FlowIssue bigint-unsupported
+  permissionsBitmask: bigint,
+  permission: ThreadPermission,
+): boolean => {
+  if (!(permission in minimallyEncodedThreadPermissions)) {
+    return false;
+  }
+  const permissionBitmask = minimallyEncodedThreadPermissions[permission];
+  invariant(
+    // TODO (atul): Update flow to `194.0.0` for bigint support
+    // $FlowIssue illegal-typeof
+    typeof permissionBitmask === 'bigint',
+    'permissionBitmask must be of type bigint',
+  );
+  return (permissionsBitmask & permissionBitmask) !== BigInt(0);
+};
+
+export {
+  minimallyEncodedThreadPermissions,
+  permissionsToBitmask,
+  hasPermission,
+};
diff --git a/lib/permissions/minimally-encoded-thread-permissions.test.js b/lib/permissions/minimally-encoded-thread-permissions.test.js
new file mode 100644
--- /dev/null
+++ b/lib/permissions/minimally-encoded-thread-permissions.test.js
@@ -0,0 +1,55 @@
+// @flow
+
+import {
+  hasPermission,
+  permissionsToBitmask,
+} from './minimally-encoded-thread-permissions.js';
+
+describe('minimallyEncodedThreadPermissions', () => {
+  const permissions = {
+    know_of: { value: true, source: '1' },
+    membership: { value: false, source: null },
+    visible: { value: true, source: '1' },
+    voiced: { value: true, source: '1' },
+    edit_entries: { value: true, source: '1' },
+    edit_thread: { value: true, source: '1' },
+    edit_thread_description: { value: true, source: '1' },
+    edit_thread_color: { value: true, source: '1' },
+    delete_thread: { value: true, source: '1' },
+    create_subthreads: { value: true, source: '1' },
+    create_sidebars: { value: true, source: '1' },
+    join_thread: { value: false, source: null },
+    edit_permissions: { value: false, source: null },
+    add_members: { value: true, source: '1' },
+    remove_members: { value: true, source: '1' },
+    change_role: { value: true, source: '1' },
+    leave_thread: { value: false, source: null },
+    react_to_message: { value: true, source: '1' },
+    edit_message: { value: true, source: '1' },
+  };
+
+  it('should encode ThreadPermissionsInfo as bitmask', () => {
+    const permissionsBitmask = permissionsToBitmask(permissions);
+    expect(permissionsBitmask.toString(2)).toBe('1101110011111111101');
+    expect(hasPermission(permissionsBitmask, 'know_of')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'membership')).toBe(false);
+    expect(hasPermission(permissionsBitmask, 'visible')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'voiced')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'edit_entries')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'edit_thread')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'edit_thread_description')).toBe(
+      true,
+    );
+    expect(hasPermission(permissionsBitmask, 'edit_thread_color')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'delete_thread')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'create_subthreads')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'create_sidebars')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'join_thread')).toBe(false);
+    expect(hasPermission(permissionsBitmask, 'edit_permissions')).toBe(false);
+    expect(hasPermission(permissionsBitmask, 'remove_members')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'change_role')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'leave_thread')).toBe(false);
+    expect(hasPermission(permissionsBitmask, 'react_to_message')).toBe(true);
+    expect(hasPermission(permissionsBitmask, 'edit_message')).toBe(true);
+  });
+});