diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5ecfebd..faec18f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [Backend 0.8.3] - 2026-08-20
+
+### Fixed
+
+- Invalid non-string trade identifiers now return validation errors instead of server errors.
+
 ## [Backend 0.8.2] - 2026-08-20
 
 ### Added
diff --git a/backend/package.json b/backend/package.json
index 8b96d02..7dbc83a 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@family-budget/backend",
-  "version": "0.8.2",
+  "version": "0.8.3",
   "private": true,
   "scripts": {
     "dev": "tsx watch src/app.ts",
diff --git a/backend/src/services/portfolio.test.ts b/backend/src/services/portfolio.test.ts
index 3ad6c11..ef5f73e 100644
--- a/backend/src/services/portfolio.test.ts
+++ b/backend/src/services/portfolio.test.ts
@@ -8,5 +8,6 @@ const trade = {
 
 assert.equal(deriveTradeSourceId(trade), 'RU0000000001|2026-08-20T10:00:00+03:00|Покупка|1.000|1234.50');
 assert.throws(() => validatePortfolio(null), /object/);
+assert.throws(() => validatePortfolio({ schemaVersion: 'broker-portfolio-1.0', bank: 'B', accountNumber: 'A', reportPeriod: { from: '2026-08-20', to: '2026-08-20' }, reportedAt: null, positions: [], trades: [{ ...trade, sourceId: 42 }] }), /sourceId/);
 assert.throws(() => validatePortfolio({ ...{ schemaVersion: 'broker-portfolio-1.0', bank: 'B', accountNumber: 'A', reportPeriod: { from: '2026-08-21', to: '2026-08-20' }, reportedAt: null, positions: [], trades: [] } }), /period/);
 console.log('portfolio validation: OK');
diff --git a/backend/src/services/portfolio.ts b/backend/src/services/portfolio.ts
index da406f1..19ceb3c 100644
--- a/backend/src/services/portfolio.ts
+++ b/backend/src/services/portfolio.ts
@@ -29,6 +29,8 @@ export function validatePortfolio(body: unknown): asserts body is PortfolioFile
   const sourceIds = new Set<string>();
   for (const trade of data.trades) {
     if (!trade || typeof trade.instrument !== 'string' || !trade.instrument.trim() || typeof trade.concludedAt !== 'string' || Number.isNaN(Date.parse(trade.concludedAt)) || typeof trade.side !== 'string' || !trade.side.trim()) throw new Error('Invalid trade');
+    if (trade.sourceId !== undefined && typeof trade.sourceId !== 'string') throw new Error('sourceId must be a string');
+    if (trade.operationId !== undefined && typeof trade.operationId !== 'string') throw new Error('operationId must be a string');
     const sourceId = deriveTradeSourceId(trade);
     if (sourceIds.has(sourceId)) throw new Error(`Duplicate sourceId: ${sourceId}`);
     sourceIds.add(sourceId);