diff --git a/scripts/test-api.js b/scripts/test-api.js
index 64b4a6d..45e20aa 100644
--- a/scripts/test-api.js
+++ b/scripts/test-api.js
@@ -27,6 +27,19 @@ function printResult(label, value) {
   console.log();
 }
 
+async function askText(message, { placeholder, validate } = {}) {
+  const value = await p.text({ message, placeholder, validate });
+  if (p.isCancel(value)) return null;
+  return value.trim();
+}
+
+async function askInt(message, placeholder = '1') {
+  return askText(message, {
+    placeholder,
+    validate: (v) => (!/^\d+$/.test(v?.trim() ?? '') ? 'Integer required' : undefined),
+  });
+}
+
 async function shutdown(pool, code = 0) {
   try {
     await pool.close();
@@ -36,6 +49,146 @@ async function shutdown(pool, code = 0) {
   process.exit(code);
 }
 
+const METHODS = [
+  { value: 'company.create', label: 'company.create', hint: '{name} → id' },
+  { value: 'company.list', label: 'company.list', hint: '→ rows' },
+  { value: 'company.setDefaultLang', label: 'company.setDefaultLang', hint: 'companyId, langId' },
+  { value: 'company.setRootCategory', label: 'company.setRootCategory', hint: 'companyId, categoryId' },
+  { value: 'company.delete', label: 'company.delete', hint: 'companyId' },
+  { value: 'company.getByCompanyUserId', label: 'company.getByCompanyUserId', hint: 'id → tuple' },
+  { value: 'lang.create', label: 'lang.create', hint: 'iso639 → id' },
+  { value: 'lang.list', label: 'lang.list', hint: '→ rows' },
+  { value: 'lang.delete', label: 'lang.delete', hint: 'id' },
+  { value: 'category.create', label: 'category.create', hint: '{parent_id, sort} → id' },
+  { value: 'category.getTree', label: 'category.getTree', hint: 'rootId → rows' },
+  { value: 'companyuser.add', label: 'companyuser.add', hint: 'companyId, authId → id' },
+  { value: 'companyuser.getByEmail', label: 'companyuser.getByEmail', hint: 'email → ids' },
+  { value: 'google_auth.add', label: 'google_auth.add', hint: 'email → authId' },
+  { value: 'google_auth.list', label: 'google_auth.list', hint: '→ rows' },
+  { value: 'google_auth.del', label: 'google_auth.del', hint: 'id' },
+  { value: 'initialize', label: 'initialize', hint: 'purge + recreate' },
+  { value: 'purge', label: chalk.red('purge'), hint: 'drop all · exit' },
+  { value: 'exit', label: 'exit', hint: 'quit without purge' },
+];
+
+async function runMethod(client, action) {
+  switch (action) {
+    case 'company.create': {
+      const name = await askText('Name', {
+        placeholder: 'Acme',
+        validate: (v) => (!v?.trim() ? 'Required' : undefined),
+      });
+      if (name == null) return;
+      return ['id', await client.company.create({ name })];
+    }
+    case 'company.list': {
+      return ['rows', await client.company.list()];
+    }
+    case 'company.setDefaultLang': {
+      const companyId = await askInt('Company id');
+      if (companyId == null) return;
+      const languageId = await askInt('Language id');
+      if (languageId == null) return;
+      await client.company.setDefaultLang(Number(companyId), Number(languageId));
+      return ['ok', true];
+    }
+    case 'company.setRootCategory': {
+      const companyId = await askInt('Company id');
+      if (companyId == null) return;
+      const categoryId = await askInt('Category id');
+      if (categoryId == null) return;
+      await client.company.setRootCategory(Number(companyId), Number(categoryId));
+      return ['ok', true];
+    }
+    case 'company.delete': {
+      const companyId = await askInt('Company id');
+      if (companyId == null) return;
+      await client.company.delete(Number(companyId));
+      return ['ok', true];
+    }
+    case 'company.getByCompanyUserId': {
+      const id = await askInt('Company user id');
+      if (id == null) return;
+      return [
+        '[id, defaultLangId, rootCategoryId, name]',
+        await client.company.getByCompanyUserId(Number(id)),
+      ];
+    }
+    case 'lang.create': {
+      const iso639 = await askText('ISO 639', {
+        placeholder: 'de',
+        validate: (v) => (!v?.trim() ? 'Required' : undefined),
+      });
+      if (iso639 == null) return;
+      return ['id', await client.lang.create(iso639)];
+    }
+    case 'lang.list': {
+      return ['rows', await client.lang.list()];
+    }
+    case 'lang.delete': {
+      const id = await askInt('Language id');
+      if (id == null) return;
+      await client.lang.delete(Number(id));
+      return ['ok', true];
+    }
+    case 'category.create': {
+      const parentRaw = await askText('parent_id (null as empty)', {
+        placeholder: '',
+        validate: (v) =>
+          v?.trim() && !/^\d+$/.test(v.trim()) ? 'Integer or empty' : undefined,
+      });
+      if (parentRaw == null) return;
+      const sortRaw = await askInt('sort', '0');
+      if (sortRaw == null) return;
+      const parent_id = parentRaw === '' ? null : Number(parentRaw);
+      return ['id', await client.category.create({ parent_id, sort: Number(sortRaw) })];
+    }
+    case 'category.getTree': {
+      const rootId = await askInt('Root category id');
+      if (rootId == null) return;
+      return ['rows', await client.category.getTree(Number(rootId))];
+    }
+    case 'companyuser.add': {
+      const companyId = await askInt('Company id');
+      if (companyId == null) return;
+      const authId = await askInt('Auth id');
+      if (authId == null) return;
+      return ['id', await client.companyuser.add(Number(companyId), Number(authId))];
+    }
+    case 'companyuser.getByEmail': {
+      const email = await askText('Email', {
+        placeholder: 'user@example.com',
+        validate: (v) => (!v?.trim() ? 'Required' : undefined),
+      });
+      if (email == null) return;
+      return ['ids', await client.companyuser.getByEmail(email)];
+    }
+    case 'google_auth.add': {
+      const email = await askText('Email', {
+        placeholder: 'user@example.com',
+        validate: (v) => (!v?.trim() ? 'Required' : undefined),
+      });
+      if (email == null) return;
+      return ['authId', await client.google_auth.add(email)];
+    }
+    case 'google_auth.list': {
+      return ['rows', await client.google_auth.list()];
+    }
+    case 'google_auth.del': {
+      const id = await askInt('Auth id');
+      if (id == null) return;
+      await client.google_auth.del(Number(id));
+      return ['ok', true];
+    }
+    case 'initialize': {
+      await client.initialize();
+      return ['ok', true];
+    }
+    default:
+      return null;
+  }
+}
+
 async function main() {
   console.clear();
   p.intro(chalk.bgMagenta.black(' libdashstore ') + chalk.dim('  api tester'));
@@ -75,34 +228,7 @@ async function main() {
   while (true) {
     const action = await p.select({
       message: 'API method',
-      options: [
-        {
-          value: 'companyuser.getByEmail',
-          label: 'companyuser.getByEmail',
-          hint: 'email → id',
-        },
-        {
-          value: 'company.getByCompanyUserId',
-          label: 'company.getByCompanyUserId',
-          hint: 'id → [id, lang, root, name]',
-        },
-        {
-          value: 'category.getTree',
-          label: 'category.getTree',
-          hint: 'rootId → tree',
-        },
-        {
-          value: 'initialize',
-          label: 'initialize',
-          hint: 'purge + recreate schema',
-        },
-        {
-          value: 'purge',
-          label: chalk.red('purge'),
-          hint: 'drop all · exit',
-        },
-        { value: 'exit', label: 'exit', hint: 'quit without purge' },
-      ],
+      options: METHODS,
     });
 
     if (p.isCancel(action) || action === 'exit') {
@@ -110,74 +236,20 @@ async function main() {
       await shutdown(pool, 0);
     }
 
+    if (action === 'purge') {
+      const run = p.spinner();
+      run.start('Purging…');
+      await client.purge();
+      run.stop(chalk.green('purge'));
+      p.outro(chalk.red('Database purged — exiting'));
+      await shutdown(pool, 0);
+    }
+
     try {
-      if (action === 'companyuser.getByEmail') {
-        const email = await p.text({
-          message: 'Email',
-          placeholder: 'user@example.com',
-          validate: (v) => (!v?.trim() ? 'Required' : undefined),
-        });
-        if (p.isCancel(email)) continue;
-
-        const run = p.spinner();
-        run.start('Running…');
-        const id = await client.companyuser.getByEmail(email.trim());
-        run.stop(chalk.green('companyuser.getByEmail'));
-        printResult('id', id);
-        continue;
-      }
-
-      if (action === 'company.getByCompanyUserId') {
-        const raw = await p.text({
-          message: 'Company user id',
-          placeholder: '1',
-          validate: (v) =>
-            !/^\d+$/.test(v?.trim() ?? '') ? 'Integer required' : undefined,
-        });
-        if (p.isCancel(raw)) continue;
-
-        const run = p.spinner();
-        run.start('Running…');
-        const row = await client.company.getByCompanyUserId(Number(raw.trim()));
-        run.stop(chalk.green('company.getByCompanyUserId'));
-        printResult('[id, defaultLangId, rootCategoryId, name]', row);
-        continue;
-      }
-
-      if (action === 'category.getTree') {
-        const raw = await p.text({
-          message: 'Root category id',
-          placeholder: '1',
-          validate: (v) =>
-            !/^\d+$/.test(v?.trim() ?? '') ? 'Integer required' : undefined,
-        });
-        if (p.isCancel(raw)) continue;
-
-        const run = p.spinner();
-        run.start('Running…');
-        const tree = await client.category.getTree(Number(raw.trim()));
-        run.stop(chalk.green('category.getTree'));
-        printResult('tree', tree);
-        continue;
-      }
-
-      if (action === 'initialize') {
-        const run = p.spinner();
-        run.start('Initializing…');
-        await client.initialize();
-        run.stop(chalk.green('initialize'));
-        p.log.success('Schema purged and recreated');
-        console.log();
-        continue;
-      }
-
-      if (action === 'purge') {
-        const run = p.spinner();
-        run.start('Purging…');
-        await client.purge();
-        run.stop(chalk.green('purge'));
-        p.outro(chalk.red('Database purged — exiting'));
-        await shutdown(pool, 0);
+      const result = await runMethod(client, action);
+      if (result) {
+        p.log.success(action);
+        printResult(result[0], result[1]);
       }
     } catch (err) {
       p.log.error(err.message);
diff --git a/src/index.js b/src/index.js
index e7a6c91..b0ff30e 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,6 +1,19 @@
 import companyuserGetByEmail from './store/companyuser/getByEmail.js';
+import companyuserAdd from './store/companyuser/add.js';
 import companyGetByCompanyUserId from './store/company/getByCompanyUserId.js';
+import companyCreate from './store/company/create.js';
+import companySetDefaultLang from './store/company/setDefaultLang.js';
+import companySetRootCategory from './store/company/setRootCategory.js';
+import companyDelete from './store/company/delete.js';
+import companyList from './store/company/list.js';
 import categoryGetTree from './store/category/getTree.js';
+import categoryCreate from './store/category/create.js';
+import langCreate from './store/lang/create.js';
+import langDelete from './store/lang/delete.js';
+import langList from './store/lang/list.js';
+import googleAuthAdd from './store/google_auth/add.js';
+import googleAuthList from './store/google_auth/list.js';
+import googleAuthDel from './store/google_auth/del.js';
 import storePurge from './store/purge.js';
 import storeInitialize from './store/initialize.js';
 
@@ -10,14 +23,33 @@ export default class LibDashStore {
 
     this.companyuser = {
       getByEmail: companyuserGetByEmail(pool),
+      add: companyuserAdd(pool),
     };
 
     this.company = {
       getByCompanyUserId: companyGetByCompanyUserId(pool),
+      create: companyCreate(pool),
+      setDefaultLang: companySetDefaultLang(pool),
+      setRootCategory: companySetRootCategory(pool),
+      delete: companyDelete(pool),
+      list: companyList(pool),
     };
 
     this.category = {
       getTree: categoryGetTree(pool),
+      create: categoryCreate(pool),
+    };
+
+    this.lang = {
+      create: langCreate(pool),
+      delete: langDelete(pool),
+      list: langList(pool),
+    };
+
+    this.google_auth = {
+      add: googleAuthAdd(pool),
+      list: googleAuthList(pool),
+      del: googleAuthDel(pool),
     };
 
     this.purge = storePurge(pool);
diff --git a/src/sql/category.js b/src/sql/category.js
index b602e38..11313d8 100644
--- a/src/sql/category.js
+++ b/src/sql/category.js
@@ -14,3 +14,9 @@ SELECT id, parent_id, sort
 FROM tree
 ORDER BY sort, id
 `;
+
+export const CREATE = `
+INSERT INTO category (parent_id, sort)
+OUTPUT INSERTED.id
+VALUES (@parentId, @sort)
+`;
diff --git a/src/sql/company.js b/src/sql/company.js
index 0acdc63..d41b4aa 100644
--- a/src/sql/company.js
+++ b/src/sql/company.js
@@ -8,3 +8,31 @@ FROM company c
 INNER JOIN companyuser cu ON cu.company_id = c.id
 WHERE cu.id = @companyUserId
 `;
+
+export const CREATE = `
+INSERT INTO company (name)
+OUTPUT INSERTED.id
+VALUES (@name)
+`;
+
+export const LIST = `
+SELECT id, name, root_category_id, default_language_id
+FROM company
+`;
+
+export const SET_DEFAULT_LANG = `
+UPDATE company
+SET default_language_id = @languageId
+WHERE id = @companyId
+`;
+
+export const SET_ROOT_CATEGORY = `
+UPDATE company
+SET root_category_id = @categoryId
+WHERE id = @companyId
+`;
+
+export const DELETE = `
+DELETE FROM company
+WHERE id = @companyId
+`;
diff --git a/src/sql/companyuser.js b/src/sql/companyuser.js
index 7e5ca08..dfd615d 100644
--- a/src/sql/companyuser.js
+++ b/src/sql/companyuser.js
@@ -4,3 +4,9 @@ FROM companyuser cu
 INNER JOIN google_auth ga ON ga.id = cu.google_auth_id
 WHERE ga.email = @email
 `;
+
+export const ADD = `
+INSERT INTO companyuser (google_auth_id, company_id)
+OUTPUT INSERTED.id
+VALUES (@authId, @companyId)
+`;
diff --git a/src/sql/google_auth.js b/src/sql/google_auth.js
new file mode 100644
index 0000000..cfb8842
--- /dev/null
+++ b/src/sql/google_auth.js
@@ -0,0 +1,16 @@
+export const ADD = `
+INSERT INTO google_auth (email)
+OUTPUT INSERTED.id
+VALUES (@email)
+`;
+
+export const LIST = `
+SELECT id, email, created_at
+FROM google_auth
+ORDER BY id
+`;
+
+export const DEL = `
+DELETE FROM google_auth
+WHERE id = @id
+`;
diff --git a/src/sql/language.js b/src/sql/language.js
new file mode 100644
index 0000000..683ec2a
--- /dev/null
+++ b/src/sql/language.js
@@ -0,0 +1,15 @@
+export const CREATE = `
+INSERT INTO language (iso639)
+OUTPUT INSERTED.id
+VALUES (@iso639)
+`;
+
+export const LIST = `
+SELECT id, iso639
+FROM language
+`;
+
+export const DELETE = `
+DELETE FROM language
+WHERE id = @id
+`;
diff --git a/src/store/category/create.js b/src/store/category/create.js
new file mode 100644
index 0000000..2a0c748
--- /dev/null
+++ b/src/store/category/create.js
@@ -0,0 +1,14 @@
+import sql from 'mssql';
+import { CREATE } from '../../sql/category.js';
+
+export default function create(pool) {
+  return async ({ parent_id, sort }) => {
+    const result = await pool
+      .request()
+      .input('parentId', sql.Int, parent_id)
+      .input('sort', sql.Int, sort)
+      .query(CREATE);
+
+    return result.recordset[0].id;
+  };
+}
diff --git a/src/store/category/getTree.js b/src/store/category/getTree.js
index caafcb6..8ae28ac 100644
--- a/src/store/category/getTree.js
+++ b/src/store/category/getTree.js
@@ -1,30 +1,6 @@
 import sql from 'mssql';
 import { GET_TREE } from '../../sql/category.js';
 
-function buildTree(rows, rootId) {
-  const byId = new Map();
-  for (const row of rows) {
-    byId.set(row.id, {
-      id: row.id,
-      parent_id: row.parent_id,
-      sort: row.sort,
-      children: [],
-    });
-  }
-
-  let root = null;
-  for (const node of byId.values()) {
-    if (node.id === rootId) {
-      root = node;
-      continue;
-    }
-    const parent = byId.get(node.parent_id);
-    if (parent) parent.children.push(node);
-  }
-
-  return root;
-}
-
 export default function getTree(pool) {
   return async (rootId) => {
     const result = await pool
@@ -32,7 +8,6 @@ export default function getTree(pool) {
       .input('rootId', sql.Int, rootId)
       .query(GET_TREE);
 
-    if (result.recordset.length === 0) return null;
-    return buildTree(result.recordset, rootId);
+    return result.recordset;
   };
 }
diff --git a/src/store/company/create.js b/src/store/company/create.js
new file mode 100644
index 0000000..813b52d
--- /dev/null
+++ b/src/store/company/create.js
@@ -0,0 +1,13 @@
+import sql from 'mssql';
+import { CREATE } from '../../sql/company.js';
+
+export default function create(pool) {
+  return async ({ name }) => {
+    const result = await pool
+      .request()
+      .input('name', sql.NVarChar(255), name)
+      .query(CREATE);
+
+    return result.recordset[0].id;
+  };
+}
diff --git a/src/store/company/delete.js b/src/store/company/delete.js
new file mode 100644
index 0000000..6e3c9d2
--- /dev/null
+++ b/src/store/company/delete.js
@@ -0,0 +1,11 @@
+import sql from 'mssql';
+import { DELETE } from '../../sql/company.js';
+
+export default function del(pool) {
+  return async (companyId) => {
+    await pool
+      .request()
+      .input('companyId', sql.Int, companyId)
+      .query(DELETE);
+  };
+}
diff --git a/src/store/company/getByCompanyUserId.js b/src/store/company/getByCompanyUserId.js
index a430f8d..996933e 100644
--- a/src/store/company/getByCompanyUserId.js
+++ b/src/store/company/getByCompanyUserId.js
@@ -9,7 +9,7 @@ export default function getByCompanyUserId(pool) {
       .query(GET_BY_COMPANY_USER_ID);
 
     const row = result.recordset[0];
-    if (!row) return null;
+    if (!row) return;
 
     return [row.id, row.default_language_id, row.root_category_id, row.name];
   };
diff --git a/src/store/company/list.js b/src/store/company/list.js
new file mode 100644
index 0000000..9305e1a
--- /dev/null
+++ b/src/store/company/list.js
@@ -0,0 +1,8 @@
+import { LIST } from '../../sql/company.js';
+
+export default function list(pool) {
+  return async () => {
+    const result = await pool.request().query(LIST);
+    return result.recordset;
+  };
+}
diff --git a/src/store/company/setDefaultLang.js b/src/store/company/setDefaultLang.js
new file mode 100644
index 0000000..2ad3598
--- /dev/null
+++ b/src/store/company/setDefaultLang.js
@@ -0,0 +1,12 @@
+import sql from 'mssql';
+import { SET_DEFAULT_LANG } from '../../sql/company.js';
+
+export default function setDefaultLang(pool) {
+  return async (companyId, languageId) => {
+    await pool
+      .request()
+      .input('companyId', sql.Int, companyId)
+      .input('languageId', sql.Int, languageId)
+      .query(SET_DEFAULT_LANG);
+  };
+}
diff --git a/src/store/company/setRootCategory.js b/src/store/company/setRootCategory.js
new file mode 100644
index 0000000..5be9e59
--- /dev/null
+++ b/src/store/company/setRootCategory.js
@@ -0,0 +1,12 @@
+import sql from 'mssql';
+import { SET_ROOT_CATEGORY } from '../../sql/company.js';
+
+export default function setRootCategory(pool) {
+  return async (companyId, categoryId) => {
+    await pool
+      .request()
+      .input('companyId', sql.Int, companyId)
+      .input('categoryId', sql.Int, categoryId)
+      .query(SET_ROOT_CATEGORY);
+  };
+}
diff --git a/src/store/companyuser/add.js b/src/store/companyuser/add.js
new file mode 100644
index 0000000..a5b9499
--- /dev/null
+++ b/src/store/companyuser/add.js
@@ -0,0 +1,14 @@
+import sql from 'mssql';
+import { ADD } from '../../sql/companyuser.js';
+
+export default function add(pool) {
+  return async (companyId, authId) => {
+    const result = await pool
+      .request()
+      .input('companyId', sql.Int, companyId)
+      .input('authId', sql.Int, authId)
+      .query(ADD);
+
+    return result.recordset[0].id;
+  };
+}
diff --git a/src/store/companyuser/getByEmail.js b/src/store/companyuser/getByEmail.js
index 171ff88..4bfe520 100644
--- a/src/store/companyuser/getByEmail.js
+++ b/src/store/companyuser/getByEmail.js
@@ -8,6 +8,6 @@ export default function getByEmail(pool) {
       .input('email', sql.NVarChar(320), email)
       .query(GET_BY_EMAIL);
 
-    return result.recordset[0]?.id ?? null;
+    return result.recordset.map((row) => row.id);
   };
 }
diff --git a/src/store/google_auth/add.js b/src/store/google_auth/add.js
new file mode 100644
index 0000000..3360df2
--- /dev/null
+++ b/src/store/google_auth/add.js
@@ -0,0 +1,13 @@
+import sql from 'mssql';
+import { ADD } from '../../sql/google_auth.js';
+
+export default function add(pool) {
+  return async (email) => {
+    const result = await pool
+      .request()
+      .input('email', sql.NVarChar(320), email)
+      .query(ADD);
+
+    return result.recordset[0].id;
+  };
+}
diff --git a/src/store/google_auth/del.js b/src/store/google_auth/del.js
new file mode 100644
index 0000000..9bf3f79
--- /dev/null
+++ b/src/store/google_auth/del.js
@@ -0,0 +1,11 @@
+import sql from 'mssql';
+import { DEL } from '../../sql/google_auth.js';
+
+export default function del(pool) {
+  return async (id) => {
+    await pool
+      .request()
+      .input('id', sql.Int, id)
+      .query(DEL);
+  };
+}
diff --git a/src/store/google_auth/list.js b/src/store/google_auth/list.js
new file mode 100644
index 0000000..7f9e765
--- /dev/null
+++ b/src/store/google_auth/list.js
@@ -0,0 +1,8 @@
+import { LIST } from '../../sql/google_auth.js';
+
+export default function list(pool) {
+  return async () => {
+    const result = await pool.request().query(LIST);
+    return result.recordset;
+  };
+}
diff --git a/src/store/lang/create.js b/src/store/lang/create.js
new file mode 100644
index 0000000..1337305
--- /dev/null
+++ b/src/store/lang/create.js
@@ -0,0 +1,13 @@
+import sql from 'mssql';
+import { CREATE } from '../../sql/language.js';
+
+export default function create(pool) {
+  return async (iso639) => {
+    const result = await pool
+      .request()
+      .input('iso639', sql.NVarChar(10), iso639)
+      .query(CREATE);
+
+    return result.recordset[0].id;
+  };
+}
diff --git a/src/store/lang/delete.js b/src/store/lang/delete.js
new file mode 100644
index 0000000..b863ae0
--- /dev/null
+++ b/src/store/lang/delete.js
@@ -0,0 +1,11 @@
+import sql from 'mssql';
+import { DELETE } from '../../sql/language.js';
+
+export default function del(pool) {
+  return async (id) => {
+    await pool
+      .request()
+      .input('id', sql.Int, id)
+      .query(DELETE);
+  };
+}
diff --git a/src/store/lang/list.js b/src/store/lang/list.js
new file mode 100644
index 0000000..fc259f3
--- /dev/null
+++ b/src/store/lang/list.js
@@ -0,0 +1,8 @@
+import { LIST } from '../../sql/language.js';
+
+export default function list(pool) {
+  return async () => {
+    const result = await pool.request().query(LIST);
+    return result.recordset;
+  };
+}