diff --git a/web/src/store/mail.ts b/web/src/store/mail/index.ts
similarity index 88%
rename from web/src/store/mail.ts
rename to web/src/store/mail/index.ts
index e13eeb4..5dbe583 100644
--- a/web/src/store/mail.ts
+++ b/web/src/store/mail/index.ts
@@ -1,7 +1,6 @@
 import { create } from "zustand";
 import type { FolderRef } from "@/lib/sieveFolders";
-import { SPAM_HEADER_PROPS } from "@/lib/spamScore";
-import { groupByArchivePath, archivePath, type ArchiveGranularity } from "@/lib/archiveDate";
+import { groupByArchivePath, archivePath } from "@/lib/archiveDate";
 import { isOptionalSort, withoutOptionalSorts } from "@/lib/listSort";
 import { JmapMethodError, chunk, client, setErrorMessage } from "@/jmap/client";
 import type {
@@ -12,7 +11,6 @@ import type {
   Id,
   Identity,
   Mailbox,
-  MailboxRole,
   QueryResponse,
   Quota,
   SetError,
@@ -23,198 +21,28 @@ import type {
   Invocation,
 } from "@/jmap/types";
 import { toast } from "@/ui/toast";
-import { settings, useSettings } from "./settings";
-import { useSession } from "./session";
+import { settings, useSettings } from "../settings";
+import { useSession } from "../session";
 import { mailboxDisplayName } from "@/lib/mailboxName";
 import { plural, t } from "@/lib/i18n";
 import { withBase } from "@/lib/basePath";
+import { MAILBOX_PROPS, LIST_PROPS, FULL_PROPS, BODY_PROPS } from "./props";
+import { type ListQuery, type MailState } from "./types";
 
 /*
- * Named explicitly so `shareWith` comes back, which it does not otherwise --
- * see the note on CALENDAR_PROPS and the KNOWN-ISSUES entry. Mailboxes were the
- * third and last store fetching everything by asking for nothing.
- *
- * It matters here for one narrow but real case. Sharing a mail folder is
- * withdrawn because Stalwart stores the share and never delivers it, and the
- * only way left to clear one already made is the "Stop sharing" entry, which
- * appears only when a folder looks shared. Without this it never looked shared,
- * so the escape hatch for the exact situation it was built for was invisible.
+ * `@/store/mail` stays the one public entry. The split below is about file
+ * size -- 1,463 lines in a single module -- not about asking the 36 call sites
+ * that import `useMail` to learn which half of the store a symbol moved to.
+ * Anything exported before is still exported from here.
  */
-export const MAILBOX_PROPS = [
-  "id",
-  "name",
-  "parentId",
-  "role",
-  "sortOrder",
-  "totalEmails",
-  "unreadEmails",
-  "totalThreads",
-  "unreadThreads",
-  "myRights",
-  "isSubscribed",
-  "shareWith",
-];
-
-export const LIST_PROPS = [
-  "id",
-  "blobId",
-  "threadId",
-  "mailboxIds",
-  "keywords",
-  "hasAttachment",
-  "from",
-  "to",
-  "subject",
-  "receivedAt",
-  "sentAt",
-  "size",
-  "preview",
-];
-
-export const FULL_PROPS = [
-  ...LIST_PROPS,
-  "messageId",
-  "inReplyTo",
-  "references",
-  "sender",
-  "cc",
-  "bcc",
-  "replyTo",
-  "bodyStructure",
-  "bodyValues",
-  "textBody",
-  "htmlBody",
-  "attachments",
-  "header:List-Unsubscribe:asText",
-  "header:List-Unsubscribe-Post:asText",
-  "header:List-Id:asText",
-  "header:Disposition-Notification-To:asAddresses",
-  "header:X-Priority:asText",
-  "header:Importance:asText",
-  "header:Auto-Submitted:asText",
-  "header:Precedence:asText",
-  "header:Authentication-Results:asText",
-  ...SPAM_HEADER_PROPS,
-];
-
-export const BODY_PROPS = ["partId", "blobId", "size", "name", "type", "charset", "disposition", "cid", "language", "location", "subParts", "headers"];
-
-export interface ListQuery {
-  key: string;
-  filter: EmailFilter;
-  sort: Comparator[];
-  collapseThreads: boolean;
-  mailboxId: string | null;
-  label?: string;
-}
-
-export interface ListState extends ListQuery {
-  ids: Id[];
-  total: number;
-  queryState: string | null;
-  loading: boolean;
-  loadingMore: boolean;
-  error: string | null;
-  exhausted: boolean;
-}
-
-export interface MailState {
-  accountId: Id | null;
-  mailboxes: Record<Id, Mailbox>;
-  mailboxState: string | null;
-  mailboxesLoaded: boolean;
-  emails: Record<Id, Email>;
-  fullIds: Record<Id, true>;
-  emailState: string | null;
-  threads: Record<Id, Thread>;
-  identities: Identity[];
-  quotas: Quota[];
-  vacation: VacationResponse | null;
-  list: ListState | null;
-  selected: Record<Id, true>;
-  /** Unread messages per label keyword, for the sidebar. */
-  labelCounts: Record<string, number>;
-  /**
-   * The selection means "everything the current query matches", not the rows
-   * that happen to be loaded. Ticking the header box selects the loaded page;
-   * this is the deliberate second step past it.
-   */
-  selectedAll: boolean;
-  anchorId: Id | null;
-  loadingThreads: Record<Id, true>;
-  lastSeenInboxEmailIds: Id[] | null;
-  openThreadId: Id | null;
-  setOpenThread(id: Id | null): void;
-
-  setAccount(accountId: Id | null): void;
-  loadMailboxes(): Promise<void>;
-  roleId(role: MailboxRole): Id | null;
-  mailboxPath(id: Id): string;
-  childrenOf(parentId: Id | null): Mailbox[];
-
-  query(q: ListQuery, opts?: { reset?: boolean }): Promise<void>;
-  loadMore(): Promise<void>;
-  refreshList(): Promise<void>;
-
-  getEmails(ids: Id[], full?: boolean): Promise<Email[]>;
-  loadThread(threadId: Id): Promise<Email[]>;
-  threadEmails(threadId: Id): Email[];
-  threadIdsIn(threadId: Id, mailboxId: Id | null): Id[];
-
-  setKeyword(ids: Id[], keyword: string, value: boolean): Promise<void>;
-  markRead(ids: Id[], read: boolean): Promise<void>;
-  star(ids: Id[], on: boolean): Promise<void>;
-  move(ids: Id[], toMailboxId: Id, opts?: { fromMailboxId?: Id | null; silent?: boolean; label?: string }): Promise<void>;
-  addToMailbox(ids: Id[], mailboxId: Id, add: boolean): Promise<void>;
-  trash(ids: Id[]): Promise<void>;
-  destroy(ids: Id[]): Promise<void>;
-  archive(ids: Id[]): Promise<void>;
-  /** Archive into a dated subfolder of Archive, creating the folders as needed. */
-  archiveByDate(ids: Id[], granularity: ArchiveGranularity): Promise<void>;
-  spam(ids: Id[], isSpam: boolean): Promise<void>;
-  emptyMailbox(mailboxId: Id): Promise<void>;
-  /** Mark every unread message in a mailbox read; optionally its subfolders too. */
-  markMailboxRead(mailboxId: Id, includeChildren?: boolean): Promise<void>;
-  /** The mailbox plus all of its descendants. */
-  descendantMailboxIds(mailboxId: Id): Id[];
-
-  createMailbox(name: string, parentId: Id | null, role?: MailboxRole): Promise<Id>;
-  /** Give something the Archive role -- adopting a folder already named for it, or making one. */
-  ensureArchiveFolder(): Promise<Id>;
-  updateMailbox(id: Id, patch: Partial<Mailbox>): Promise<void>;
-  destroyMailbox(id: Id, removeEmails?: boolean): Promise<void>;
-
-  loadIdentities(): Promise<Identity[]>;
-  /** The user's preferred identity (falls back to the first one). */
-  defaultIdentity(): Identity | undefined;
-  setDefaultIdentity(id: Id): void;
-  saveIdentity(id: Id | null, patch: Partial<Identity>): Promise<void>;
-  destroyIdentity(id: Id): Promise<void>;
-  loadVacation(): Promise<void>;
-  saveVacation(patch: Partial<VacationResponse>): Promise<void>;
-  loadQuota(): Promise<void>;
-
-  select(ids: Id[], on: boolean): void;
-  clearSelection(): void;
-  /** Refresh the per-label unread counts, in one request. */
-  loadLabelCounts(): Promise<void>;
-  selectAll(): void;
-  /** Extend the selection from the loaded rows to everything the query matches. */
-  selectAllMatching(): void;
-  /** Every id the current query matches, walked a page at a time. */
-  queryAllIds(): Promise<Id[]>;
-  setAnchor(id: Id | null): void;
-
-  applyChanges(types: Set<string>): Promise<void>;
-  importEml(blobId: Id, mailboxId: Id, keywords?: Record<string, boolean>): Promise<Id | null>;
-}
+export { MAILBOX_PROPS, LIST_PROPS, FULL_PROPS, BODY_PROPS } from "./props";
+export { DEFAULT_SORT, type ListQuery, type ListState, type MailState } from "./types";
+export { mailboxIcon, ROLE_ORDER } from "./mailboxes";
 
 function listKey(q: { filter: EmailFilter; sort: Comparator[]; collapseThreads: boolean }): string {
   return JSON.stringify([q.filter, q.sort, q.collapseThreads]);
 }
 
-export const DEFAULT_SORT: Comparator[] = [{ property: "receivedAt", isAscending: false }];
-
 /**
  * Nothing carries the Archive role, so offer to fix it rather than explain it.
  *
@@ -1346,32 +1174,7 @@ useSession.subscribe((s) => {
   useMail.getState().setAccount(s.status === "authenticated" ? s.accountId : null);
 });
 
-export function mailboxIcon(role: MailboxRole): string {
-  switch (role) {
-    case "inbox":
-      return "inbox";
-    case "drafts":
-      return "file";
-    case "sent":
-      return "send";
-    case "trash":
-      return "trash";
-    case "junk":
-      return "alert";
-    case "archive":
-      return "archive";
-    case "all":
-      return "mail";
-    case "flagged":
-      return "star";
-    case "important":
-      return "tag";
-    default:
-      return "folder";
-  }
-}
 
-export const ROLE_ORDER: Record<string, number> = { inbox: 0, flagged: 1, important: 2, drafts: 3, sent: 4, archive: 5, all: 6, junk: 7, trash: 8 };
 
 /**
  * Resolve `parentId/segments...` to a mailbox id, creating what is missing.
@@ -1426,7 +1229,7 @@ function folderRefs(state: MailState, id: Id): FolderRef[] {
  */
 async function followFolders(before: FolderRef[]): Promise<void> {
   try {
-    const { useSieve } = await import("./sieve");
+    const { useSieve } = await import("../sieve");
     const sieve = useSieve.getState();
     if (!sieve.available) return;
     if (!sieve.scripts.length) await sieve.load();
diff --git a/web/src/store/mail/mailboxes.ts b/web/src/store/mail/mailboxes.ts
new file mode 100644
index 0000000..c4d7873
--- /dev/null
+++ b/web/src/store/mail/mailboxes.ts
@@ -0,0 +1,28 @@
+import type { MailboxRole } from "@/jmap/types";
+
+export function mailboxIcon(role: MailboxRole): string {
+  switch (role) {
+    case "inbox":
+      return "inbox";
+    case "drafts":
+      return "file";
+    case "sent":
+      return "send";
+    case "trash":
+      return "trash";
+    case "junk":
+      return "alert";
+    case "archive":
+      return "archive";
+    case "all":
+      return "mail";
+    case "flagged":
+      return "star";
+    case "important":
+      return "tag";
+    default:
+      return "folder";
+  }
+}
+
+export const ROLE_ORDER: Record<string, number> = { inbox: 0, flagged: 1, important: 2, drafts: 3, sent: 4, archive: 5, all: 6, junk: 7, trash: 8 };
diff --git a/web/src/store/mail/props.ts b/web/src/store/mail/props.ts
new file mode 100644
index 0000000..48f3c81
--- /dev/null
+++ b/web/src/store/mail/props.ts
@@ -0,0 +1,72 @@
+import { SPAM_HEADER_PROPS } from "@/lib/spamScore";
+
+
+/*
+ * Named explicitly so `shareWith` comes back, which it does not otherwise --
+ * see the note on CALENDAR_PROPS and the KNOWN-ISSUES entry. Mailboxes were the
+ * third and last store fetching everything by asking for nothing.
+ *
+ * It matters here for one narrow but real case. Sharing a mail folder is
+ * withdrawn because Stalwart stores the share and never delivers it, and the
+ * only way left to clear one already made is the "Stop sharing" entry, which
+ * appears only when a folder looks shared. Without this it never looked shared,
+ * so the escape hatch for the exact situation it was built for was invisible.
+ */
+export const MAILBOX_PROPS = [
+  "id",
+  "name",
+  "parentId",
+  "role",
+  "sortOrder",
+  "totalEmails",
+  "unreadEmails",
+  "totalThreads",
+  "unreadThreads",
+  "myRights",
+  "isSubscribed",
+  "shareWith",
+];
+
+export const LIST_PROPS = [
+  "id",
+  "blobId",
+  "threadId",
+  "mailboxIds",
+  "keywords",
+  "hasAttachment",
+  "from",
+  "to",
+  "subject",
+  "receivedAt",
+  "sentAt",
+  "size",
+  "preview",
+];
+
+export const FULL_PROPS = [
+  ...LIST_PROPS,
+  "messageId",
+  "inReplyTo",
+  "references",
+  "sender",
+  "cc",
+  "bcc",
+  "replyTo",
+  "bodyStructure",
+  "bodyValues",
+  "textBody",
+  "htmlBody",
+  "attachments",
+  "header:List-Unsubscribe:asText",
+  "header:List-Unsubscribe-Post:asText",
+  "header:List-Id:asText",
+  "header:Disposition-Notification-To:asAddresses",
+  "header:X-Priority:asText",
+  "header:Importance:asText",
+  "header:Auto-Submitted:asText",
+  "header:Precedence:asText",
+  "header:Authentication-Results:asText",
+  ...SPAM_HEADER_PROPS,
+];
+
+export const BODY_PROPS = ["partId", "blobId", "size", "name", "type", "charset", "disposition", "cid", "language", "location", "subParts", "headers"];
diff --git a/web/src/store/mail/types.ts b/web/src/store/mail/types.ts
new file mode 100644
index 0000000..afb3d11
--- /dev/null
+++ b/web/src/store/mail/types.ts
@@ -0,0 +1,125 @@
+import type { ArchiveGranularity } from "@/lib/archiveDate";
+import type {
+  Comparator,
+  Email,
+  EmailFilter,
+  Id,
+  Identity,
+  Mailbox,
+  MailboxRole,
+  Quota,
+  Thread,
+  VacationResponse,
+} from "@/jmap/types";
+
+export interface ListQuery {
+  key: string;
+  filter: EmailFilter;
+  sort: Comparator[];
+  collapseThreads: boolean;
+  mailboxId: string | null;
+  label?: string;
+}
+
+export interface ListState extends ListQuery {
+  ids: Id[];
+  total: number;
+  queryState: string | null;
+  loading: boolean;
+  loadingMore: boolean;
+  error: string | null;
+  exhausted: boolean;
+}
+
+export interface MailState {
+  accountId: Id | null;
+  mailboxes: Record<Id, Mailbox>;
+  mailboxState: string | null;
+  mailboxesLoaded: boolean;
+  emails: Record<Id, Email>;
+  fullIds: Record<Id, true>;
+  emailState: string | null;
+  threads: Record<Id, Thread>;
+  identities: Identity[];
+  quotas: Quota[];
+  vacation: VacationResponse | null;
+  list: ListState | null;
+  selected: Record<Id, true>;
+  /** Unread messages per label keyword, for the sidebar. */
+  labelCounts: Record<string, number>;
+  /**
+   * The selection means "everything the current query matches", not the rows
+   * that happen to be loaded. Ticking the header box selects the loaded page;
+   * this is the deliberate second step past it.
+   */
+  selectedAll: boolean;
+  anchorId: Id | null;
+  loadingThreads: Record<Id, true>;
+  lastSeenInboxEmailIds: Id[] | null;
+  openThreadId: Id | null;
+  setOpenThread(id: Id | null): void;
+
+  setAccount(accountId: Id | null): void;
+  loadMailboxes(): Promise<void>;
+  roleId(role: MailboxRole): Id | null;
+  mailboxPath(id: Id): string;
+  childrenOf(parentId: Id | null): Mailbox[];
+
+  query(q: ListQuery, opts?: { reset?: boolean }): Promise<void>;
+  loadMore(): Promise<void>;
+  refreshList(): Promise<void>;
+
+  getEmails(ids: Id[], full?: boolean): Promise<Email[]>;
+  loadThread(threadId: Id): Promise<Email[]>;
+  threadEmails(threadId: Id): Email[];
+  threadIdsIn(threadId: Id, mailboxId: Id | null): Id[];
+
+  setKeyword(ids: Id[], keyword: string, value: boolean): Promise<void>;
+  markRead(ids: Id[], read: boolean): Promise<void>;
+  star(ids: Id[], on: boolean): Promise<void>;
+  move(ids: Id[], toMailboxId: Id, opts?: { fromMailboxId?: Id | null; silent?: boolean; label?: string }): Promise<void>;
+  addToMailbox(ids: Id[], mailboxId: Id, add: boolean): Promise<void>;
+  trash(ids: Id[]): Promise<void>;
+  destroy(ids: Id[]): Promise<void>;
+  archive(ids: Id[]): Promise<void>;
+  /** Archive into a dated subfolder of Archive, creating the folders as needed. */
+  archiveByDate(ids: Id[], granularity: ArchiveGranularity): Promise<void>;
+  spam(ids: Id[], isSpam: boolean): Promise<void>;
+  emptyMailbox(mailboxId: Id): Promise<void>;
+  /** Mark every unread message in a mailbox read; optionally its subfolders too. */
+  markMailboxRead(mailboxId: Id, includeChildren?: boolean): Promise<void>;
+  /** The mailbox plus all of its descendants. */
+  descendantMailboxIds(mailboxId: Id): Id[];
+
+  createMailbox(name: string, parentId: Id | null, role?: MailboxRole): Promise<Id>;
+  /** Give something the Archive role -- adopting a folder already named for it, or making one. */
+  ensureArchiveFolder(): Promise<Id>;
+  updateMailbox(id: Id, patch: Partial<Mailbox>): Promise<void>;
+  destroyMailbox(id: Id, removeEmails?: boolean): Promise<void>;
+
+  loadIdentities(): Promise<Identity[]>;
+  /** The user's preferred identity (falls back to the first one). */
+  defaultIdentity(): Identity | undefined;
+  setDefaultIdentity(id: Id): void;
+  saveIdentity(id: Id | null, patch: Partial<Identity>): Promise<void>;
+  destroyIdentity(id: Id): Promise<void>;
+  loadVacation(): Promise<void>;
+  saveVacation(patch: Partial<VacationResponse>): Promise<void>;
+  loadQuota(): Promise<void>;
+
+  select(ids: Id[], on: boolean): void;
+  clearSelection(): void;
+  /** Refresh the per-label unread counts, in one request. */
+  loadLabelCounts(): Promise<void>;
+  selectAll(): void;
+  /** Extend the selection from the loaded rows to everything the query matches. */
+  selectAllMatching(): void;
+  /** Every id the current query matches, walked a page at a time. */
+  queryAllIds(): Promise<Id[]>;
+  setAnchor(id: Id | null): void;
+
+  applyChanges(types: Set<string>): Promise<void>;
+  importEml(blobId: Id, mailboxId: Id, keywords?: Record<string, boolean>): Promise<Id | null>;
+}
+
+export const DEFAULT_SORT: Comparator[] = [{ property: "receivedAt", isAscending: false }];