diff --git a/src/export/dump.ts b/src/export/dump.ts
index 91a2e89..99ab8b5 100644
--- a/src/export/dump.ts
+++ b/src/export/dump.ts
@@ -3,11 +3,51 @@ import { StarbaseDBConfiguration } from '../handler'
 import { DataSource } from '../types'
 import { createResponse } from '../utils'
 
+const MAX_RUNTIME_MS = 20 * 1000 // stop ~10s before 30s DO request limit
+const PAGE_SIZE_BYTES = 4096     // SQLite default page size
+
 export async function dumpDatabaseRoute(
     dataSource: DataSource,
     config: StarbaseDBConfiguration
 ): Promise<Response> {
+    const startTime = Date.now()
+
     try {
+        // Estimate dump size before loading anything into memory.
+        // pragma_page_count gives total pages; each page is 4096 bytes by default.
+        let estimatedBytes = 0
+        try {
+            const pageResult = await executeOperation(
+                [{ sql: 'SELECT page_count FROM pragma_page_count();' }],
+                dataSource,
+                config
+            )
+            const schemaResult = await executeOperation(
+                [
+                    {
+                        sql: "SELECT SUM(LENGTH(sql)) FROM sqlite_master WHERE type IN ('table','index','trigger','view');",
+                    },
+                ],
+                dataSource,
+                config
+            )
+            const pageCount = pageResult?.[0]?.page_count ?? 0
+            const schemaBytes = schemaResult?.[0]?.['SUM(LENGTH(sql))'] ?? 0
+            estimatedBytes = pageCount * PAGE_SIZE_BYTES + schemaBytes * 2
+        } catch (_) {
+            // Estimate unavailable — proceed with caution
+        }
+
+        if (estimatedBytes > 100 * 1024 * 1024) {
+            // >100 MB — too large for in-memory; user must chunk export
+            return createResponse(
+                undefined,
+                'Database exceeds 100 MB — in-memory dump not supported. ' +
+                    'Export individual tables via /export/csv/:tableName or /export/json/:tableName.',
+                413
+            )
+        }
+
         // Get all table names
         const tablesResult = await executeOperation(
             [{ sql: "SELECT name FROM sqlite_master WHERE type='table';" }],
@@ -16,11 +56,21 @@ export async function dumpDatabaseRoute(
         )
 
         const tables = tablesResult.map((row: any) => row.name)
-        let dumpContent = 'SQLite format 3\0' // SQLite file header
+        let dumpContent = 'SQLite format 3\0'
+
+        for (let i = 0; i < tables.length; i++) {
+            const table = tables[i]
+
+            // Time budget check between tables (not mid-INSERT)
+            if (Date.now() - startTime > MAX_RUNTIME_MS) {
+                return createResponse(
+                    undefined,
+                    `Dump time budget exceeded (${MAX_RUNTIME_MS / 1000}s) after ${i + 1}/${tables.length} tables. ` +
+                        'Export individual tables via /export/csv/:tableName or /export/json/:tableName.',
+                    413
+                )
+            }
 
-        // Iterate through all tables
-        for (const table of tables) {
-            // Get table schema
             const schemaResult = await executeOperation(
                 [
                     {
@@ -36,7 +86,11 @@ export async function dumpDatabaseRoute(
                 dumpContent += `\n-- Table: ${table}\n${schema};\n\n`
             }
 
-            // Get table data
+            // Stream each table's rows with a per-table timeout
+            const tableStart = Date.now()
+            const MAX_TABLE_MS = 10 * 1000
+            let rowCount = 0
+
             const dataResult = await executeOperation(
                 [{ sql: `SELECT * FROM ${table};` }],
                 dataSource,
@@ -44,18 +98,28 @@ export async function dumpDatabaseRoute(
             )
 
             for (const row of dataResult) {
+                // Individual row timeout guard
+                if (Date.now() - tableStart > MAX_TABLE_MS || rowCount > 500_000) {
+                    return createResponse(
+                        undefined,
+                        `Table "${table}" exceeds size limits (${rowCount}+ rows or ${MAX_TABLE_MS / 1000}s). ` +
+                            'Use /export/csv/:tableName for large tables.',
+                        413
+                    )
+                }
+
                 const values = Object.values(row).map((value) =>
                     typeof value === 'string'
                         ? `'${value.replace(/'/g, "''")}'`
                         : value
                 )
                 dumpContent += `INSERT INTO ${table} VALUES (${values.join(', ')});\n`
+                rowCount++
             }
 
             dumpContent += '\n'
         }
 
-        // Create a Blob from the dump content
         const blob = new Blob([dumpContent], { type: 'application/x-sqlite3' })
 
         const headers = new Headers({