diff --git a/electron/package.json b/electron/package.json
index a967a074..10dd69d2 100644
--- a/electron/package.json
+++ b/electron/package.json
@@ -40,7 +40,7 @@
     "fetch:export-runtime": "node sync_export_runtime.js --force",
     "fetch:export-runtime:latest": "EXPORT_RUNTIME_VERSION=latest node sync_export_runtime.js --force",
     "build:nextjs": "rm -rf resources/nextjs && rm -rf servers/nextjs/.next-build && cd servers/nextjs && cross-env BUILD_TARGET=electron npm run build && cp -r .next-build ../../resources/nextjs && cp -r app/presentation-templates ../../resources/nextjs/presentation-templates",
-    "build:fastapi": "rm -rf resources/fastapi && npm run build:vectorstore && (cp ../servers/fastapi/alembic/versions/*.py servers/fastapi/alembic/versions/ 2>/dev/null || true) && cd servers/fastapi && uv run python -m PyInstaller --distpath ../../resources server.spec",
+    "build:fastapi": "rm -rf resources/fastapi && npm run build:vectorstore && node scripts/prepare_fastapi_migrations.js && cd servers/fastapi && uv run python -m PyInstaller --distpath ../../resources server.spec",
     "generate:version": "node generate_update.js",
     "build:electron": "npm run generate:version && npm run build:export-runtime && rm -rf app_dist && tsc && node build.js",
     "build:all": "npm run clean:build && npm run setup:env && npm run build:ts && npm run install:pyinstaller && npm run build:nextjs && npm run build:fastapi && npm run build:electron",
diff --git a/electron/scripts/prepare_fastapi_migrations.js b/electron/scripts/prepare_fastapi_migrations.js
new file mode 100644
index 00000000..3dab5469
--- /dev/null
+++ b/electron/scripts/prepare_fastapi_migrations.js
@@ -0,0 +1,89 @@
+const fs = require("fs");
+const path = require("path");
+
+const projectRoot = path.resolve(__dirname, "..");
+const sourceDir = path.join(projectRoot, "..", "servers", "fastapi", "alembic", "versions");
+const targetDir = path.join(projectRoot, "servers", "fastapi", "alembic", "versions");
+
+function listPythonMigrations(dirPath) {
+  return fs
+    .readdirSync(dirPath, { withFileTypes: true })
+    .filter((entry) => entry.isFile() && entry.name.endsWith(".py"))
+    .map((entry) => entry.name)
+    .sort();
+}
+
+function extractRevisionInfo(filePath) {
+  const content = fs.readFileSync(filePath, "utf8");
+  const revisionMatch = content.match(/revision:\s*str\s*=\s*['"]([^'"]+)['"]/);
+  const downRevisionMatch = content.match(
+    /down_revision:\s*[^=]*=\s*(None|['"][^'"]+['"])/
+  );
+
+  if (!revisionMatch) {
+    throw new Error(`Missing revision id in ${filePath}`);
+  }
+  if (!downRevisionMatch) {
+    throw new Error(`Missing down_revision in ${filePath}`);
+  }
+
+  const revision = revisionMatch[1];
+  const downRaw = downRevisionMatch[1];
+  const downRevision = downRaw === "None" ? null : downRaw.slice(1, -1);
+  return { revision, downRevision };
+}
+
+function validateSingleHead(dirPath, filenames) {
+  const revisions = new Map();
+  const downRevisions = new Set();
+
+  for (const filename of filenames) {
+    const filePath = path.join(dirPath, filename);
+    const { revision, downRevision } = extractRevisionInfo(filePath);
+    if (revisions.has(revision)) {
+      throw new Error(`Duplicate revision id ${revision} in ${filename}`);
+    }
+    revisions.set(revision, filename);
+    if (downRevision) {
+      downRevisions.add(downRevision);
+    }
+  }
+
+  const heads = [...revisions.keys()].filter((revision) => !downRevisions.has(revision));
+  if (heads.length !== 1) {
+    throw new Error(
+      `Expected exactly one Alembic head, found ${heads.length}: ${heads.join(", ")}`
+    );
+  }
+}
+
+function syncMigrations() {
+  if (!fs.existsSync(sourceDir)) {
+    throw new Error(`Source migrations directory not found: ${sourceDir}`);
+  }
+  if (!fs.existsSync(targetDir)) {
+    throw new Error(`Target migrations directory not found: ${targetDir}`);
+  }
+
+  const sourceFiles = listPythonMigrations(sourceDir);
+  if (sourceFiles.length === 0) {
+    throw new Error(`No migration files found in source directory: ${sourceDir}`);
+  }
+
+  for (const filename of listPythonMigrations(targetDir)) {
+    fs.unlinkSync(path.join(targetDir, filename));
+  }
+
+  for (const filename of sourceFiles) {
+    fs.copyFileSync(path.join(sourceDir, filename), path.join(targetDir, filename));
+  }
+
+  const targetFiles = listPythonMigrations(targetDir);
+  validateSingleHead(targetDir, targetFiles);
+
+  console.log(
+    `Synced ${targetFiles.length} migration files and verified a single Alembic head.`
+  );
+}
+
+syncMigrations();
diff --git a/electron/servers/fastapi/migrations.py b/electron/servers/fastapi/migrations.py
index d6356f2c..c2b75984 100644
--- a/electron/servers/fastapi/migrations.py
+++ b/electron/servers/fastapi/migrations.py
@@ -5,6 +5,8 @@ from alembic import command
 from alembic.config import Config
 from alembic.script import ScriptDirectory
 from sqlalchemy import create_engine, inspect, text
+from alembic.script import ScriptDirectory
+from sqlalchemy import create_engine, inspect, text
 
 from utils.db_utils import get_database_url_and_connect_args
 from utils.get_env import get_migrate_database_on_startup_env
@@ -35,6 +37,12 @@ async def migrate_database_on_startup() -> None:
         raise
 
 
+def run_migrations_sync() -> None:
+    """Apply Alembic migrations to head (for CLI/scripts; no env gate)."""
+    _run_migrations()
+        raise
+
+
 def run_migrations_sync() -> None:
     """Apply Alembic migrations to head (for CLI/scripts; no env gate)."""
     _run_migrations()
diff --git a/servers/fastapi/alembic/versions/fd2ab04834cc_init.py b/servers/fastapi/alembic/versions/00b3c27a13bc_init.py
similarity index 97%
rename from servers/fastapi/alembic/versions/fd2ab04834cc_init.py
rename to servers/fastapi/alembic/versions/00b3c27a13bc_init.py
index cc863720..17fb3cc2 100644
--- a/servers/fastapi/alembic/versions/fd2ab04834cc_init.py
+++ b/servers/fastapi/alembic/versions/00b3c27a13bc_init.py
@@ -1,8 +1,8 @@
 """init
 
-Revision ID: fd2ab04834cc
+Revision ID: 00b3c27a13bc
 Revises: 
-Create Date: 2026-03-08 19:10:59.637680
+Create Date: 2026-03-08 19:12:45.478149
 
 """
 from typing import Sequence, Union
@@ -13,7 +13,7 @@ import sqlmodel
 
 
 # revision identifiers, used by Alembic.
-revision: str = 'fd2ab04834cc'
+revision: str = '00b3c27a13bc'
 down_revision: Union[str, None] = None
 branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
@@ -76,7 +76,6 @@ def upgrade() -> None:
     sa.Column('updated_at', sa.DateTime(timezone=True), nullable=False),
     sa.Column('layout', sa.JSON(), nullable=True),
     sa.Column('structure', sa.JSON(), nullable=True),
-    sa.Column('theme', sa.JSON(), nullable=True),
     sa.Column('instructions', sa.String(), nullable=True),
     sa.Column('tone', sa.String(), nullable=True),
     sa.Column('verbosity', sa.String(), nullable=True),
diff --git a/servers/fastapi/alembic/versions/82abdbc476a7_add_theme_column_to_presentations.py b/servers/fastapi/alembic/versions/82abdbc476a7_add_theme_column_to_presentations.py
new file mode 100644
index 00000000..c7282a6e
--- /dev/null
+++ b/servers/fastapi/alembic/versions/82abdbc476a7_add_theme_column_to_presentations.py
@@ -0,0 +1,31 @@
+"""add theme column to presentations
+
+Revision ID: 82abdbc476a7
+Revises: f42ad4074449
+Create Date: 2026-03-24 12:42:46.220359
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+
+# revision identifiers, used by Alembic.
+revision: str = '82abdbc476a7'
+down_revision: Union[str, None] = 'f42ad4074449'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    pass
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    pass
+    # ### end Alembic commands ###
diff --git a/servers/fastapi/alembic/versions/f42ad4074449_add_theme_column_to_presentations.py b/servers/fastapi/alembic/versions/f42ad4074449_add_theme_column_to_presentations.py
new file mode 100644
index 00000000..4cc8c46f
--- /dev/null
+++ b/servers/fastapi/alembic/versions/f42ad4074449_add_theme_column_to_presentations.py
@@ -0,0 +1,31 @@
+"""add theme column to presentations
+
+Revision ID: f42ad4074449
+Revises: 00b3c27a13bc
+Create Date: 2026-03-24 12:42:32.369006
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+import sqlmodel
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'f42ad4074449'
+down_revision: Union[str, None] = '00b3c27a13bc'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column('presentations', sa.Column('theme', sa.JSON(), nullable=True))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('presentations', 'theme')
+    # ### end Alembic commands ###
diff --git a/servers/fastapi/migrations.py b/servers/fastapi/migrations.py
index 0b2b578e..4cb75de0 100644
--- a/servers/fastapi/migrations.py
+++ b/servers/fastapi/migrations.py
@@ -3,11 +3,16 @@ from pathlib import Path
 
 from alembic import command
 from alembic.config import Config
+from alembic.script import ScriptDirectory
+from sqlalchemy import create_engine, inspect, text
 
 from utils.db_utils import get_database_url_and_connect_args
 from utils.get_env import get_migrate_database_on_startup_env
 
 
+LEGACY_BASELINE_REVISION = "00b3c27a13bc"
+
+
 async def migrate_database_on_startup() -> None:
     if get_migrate_database_on_startup_env() not in ["true", "True"]:
         return
@@ -17,6 +22,18 @@ async def migrate_database_on_startup() -> None:
         print("Migrations run successfully", flush=True)
     except Exception as exc:
         print(f"Error running migrations: {exc}", flush=True)
+        raise
+
+
+def _to_sync_database_url(database_url: str) -> str:
+    # Preserve slash counts for sqlite URLs so Windows paths stay valid.
+    if database_url.startswith("sqlite+aiosqlite:///"):
+        return "sqlite:///" + database_url[len("sqlite+aiosqlite:///") :]
+    if database_url.startswith("postgresql+asyncpg://"):
+        return "postgresql://" + database_url[len("postgresql+asyncpg://") :]
+    if database_url.startswith("mysql+aiomysql://"):
+        return "mysql://" + database_url[len("mysql+aiomysql://") :]
+    return database_url
 
 
 def _run_migrations() -> None:
@@ -29,12 +46,69 @@ def _run_migrations() -> None:
     database_url, _ = get_database_url_and_connect_args()
 
     # Alembic uses synchronous engines; strip async driver prefixes.
-    database_url = (
-        database_url
-        .replace("sqlite+aiosqlite://", "sqlite:///")
-        .replace("postgresql+asyncpg://", "postgresql://")
-        .replace("mysql+aiomysql://", "mysql://")
-    )
+    database_url = _to_sync_database_url(database_url)
 
     config.set_main_option("sqlalchemy.url", database_url)
-    command.upgrade(config, "head")
+    _stamp_legacy_database_if_needed(config, database_url)
+
+    try:
+        command.upgrade(config, "head")
+    except Exception:
+        # Safety net for edge cases; legacy DBs are stamped proactively above.
+        if _is_unversioned_populated_database(database_url):
+            _stamp_legacy_database_if_needed(config, database_url)
+            command.upgrade(config, "head")
+            return
+        raise
+
+
+def _stamp_legacy_database_if_needed(config: Config, database_url: str) -> None:
+    """
+    If the DB has app tables but no migration reference in alembic_version,
+    treat it as a legacy DB and stamp baseline before upgrading.
+    """
+    if not _is_unversioned_populated_database(database_url):
+        return
+
+    script = ScriptDirectory.from_config(config)
+    known_revisions = {rev.revision for rev in script.walk_revisions()}
+    baseline_revision = (
+        LEGACY_BASELINE_REVISION
+        if LEGACY_BASELINE_REVISION in known_revisions
+        else script.get_base()
+    )
+    print(
+        "Detected legacy database without migration reference. "
+        f"Stamping revision to {baseline_revision} before upgrading.",
+        flush=True,
+    )
+    command.stamp(config, baseline_revision)
+
+
+def _is_unversioned_populated_database(database_url: str) -> bool:
+    known_app_tables = {
+        "presentations",
+        "slides",
+        "templates",
+        "keyvaluesqlmodel",
+        "imageasset",
+        "presentation_layout_codes",
+        "async_presentation_generation_tasks",
+        "webhook_subscriptions",
+    }
+    engine = create_engine(database_url)
+    try:
+        with engine.connect() as connection:
+            inspector = inspect(connection)
+            table_names = set(inspector.get_table_names())
+            has_alembic_version_table = "alembic_version" in table_names
+            has_applied_revision = False
+            if has_alembic_version_table:
+                revision_count = connection.execute(
+                    text("SELECT COUNT(*) FROM alembic_version")
+                ).scalar_one()
+                has_applied_revision = revision_count > 0
+            has_known_app_tables = len(table_names.intersection(known_app_tables)) > 0
+            return has_known_app_tables and not has_applied_revision
+    finally:
+        engine.dispose()