diff --git a/backend/app/templates/mail_sources.html b/backend/app/templates/mail_sources.html
index 100293f..4119bde 100644
--- a/backend/app/templates/mail_sources.html
+++ b/backend/app/templates/mail_sources.html
@@ -114,6 +114,17 @@
                                                     <path d="M21 3v6h-6"></path>
                                                 </svg>
                                             </button>
+                                            <button class="btn btn-ghost btn-xs" x-on:click="openBackfill(source)" title="Backfill date range"
+                                                :disabled="Boolean(fetching[source.id])">
+                                                <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24"
+                                                    fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"
+                                                    stroke-linejoin="round">
+                                                    <rect x="3" y="4" width="18" height="18" rx="2" ry="2"></rect>
+                                                    <line x1="16" y1="2" x2="16" y2="6"></line>
+                                                    <line x1="8" y1="2" x2="8" y2="6"></line>
+                                                    <line x1="3" y1="10" x2="21" y2="10"></line>
+                                                </svg>
+                                            </button>
                                             <button class="btn btn-ghost btn-xs" x-on:click="loadImportHistory(source)" title="Import history">
                                                 <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24"
                                                     fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round"
@@ -476,6 +487,36 @@
         </div>
     </div>
 
+    <!-- Backfill modal -->
+    <div x-show="backfillSource" x-cloak
+        class="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center z-50 p-4"
+        x-on:keydown.escape.window="closeBackfill()">
+        <div class="bg-base-100 rounded-lg shadow-xl w-full max-w-sm p-6 space-y-4">
+            <div class="flex items-center justify-between">
+                <h2 class="text-lg font-semibold">Backfill Mail Source</h2>
+                <button class="btn btn-ghost btn-sm btn-circle" x-on:click="closeBackfill()">✕</button>
+            </div>
+            <div class="space-y-3">
+                <p class="text-sm text-muted-foreground" x-text="backfillSource ? backfillSource.name : ''"></p>
+                <div class="join w-full">
+                    <button type="button" class="btn btn-sm join-item flex-1" x-on:click="backfillDays = 7">7 days</button>
+                    <button type="button" class="btn btn-sm join-item flex-1" x-on:click="backfillDays = 30">30 days</button>
+                    <button type="button" class="btn btn-sm join-item flex-1" x-on:click="backfillDays = 90">90 days</button>
+                </div>
+                <label class="form-control">
+                    <span class="label-text">Days to search</span>
+                    <input type="number" class="input input-bordered" min="1" max="365" x-model.number="backfillDays">
+                </label>
+            </div>
+            <div class="flex justify-end gap-2">
+                <button class="btn btn-ghost btn-sm" x-on:click="closeBackfill()">Cancel</button>
+                <button class="btn btn-primary btn-sm" x-on:click="runBackfill()" :disabled="!validBackfillDays() || Boolean(fetching[backfillSource && backfillSource.id])">
+                    Run Backfill
+                </button>
+            </div>
+        </div>
+    </div>
+
     <!-- Delete confirmation modal -->
     <div x-show="deleteTarget" x-cloak
         class="fixed inset-0 bg-black bg-opacity-50 flex items-center justify-center z-50 p-4">
@@ -508,6 +549,8 @@ function mailSourcesApp() {
         isSaving: false,
         testing: {},
         fetching: {},
+        backfillSource: null,
+        backfillDays: 30,
         historySource: null,
         importHistory: [],
         historyLoading: false,
@@ -546,11 +589,12 @@ function mailSourcesApp() {
             }
         },
 
-        async fetchSource(source) {
+        async fetchSource(source, days = 7) {
             this.fetching[source.id] = true;
             this.feedback = { message: '', type: '' };
             try {
-                const resp = await fetch(`/api/v1/mail-sources/${source.id}/fetch`, {
+                const safeDays = Math.min(365, Math.max(1, Number(days) || 7));
+                const resp = await fetch(`/api/v1/mail-sources/${source.id}/fetch?days=${safeDays}`, {
                     method: 'POST',
                 });
                 const result = await resp.json();
@@ -558,7 +602,7 @@ function mailSourcesApp() {
                     throw new Error(result.detail || 'Import failed');
                 }
                 this.feedback = {
-                    message: `Import finished for ${source.name}: ${result.reports_found} report${result.reports_found === 1 ? '' : 's'}, ${result.duplicate_reports || 0} duplicate${result.duplicate_reports === 1 ? '' : 's'}.`,
+                    message: `Import finished for ${source.name} (${safeDays} day${safeDays === 1 ? '' : 's'}): ${result.reports_found} report${result.reports_found === 1 ? '' : 's'}, ${result.duplicate_reports || 0} duplicate${result.duplicate_reports === 1 ? '' : 's'}.`,
                     type: result.success ? 'success' : 'error',
                 };
                 await this.loadSources();
@@ -573,6 +617,30 @@ function mailSourcesApp() {
             }
         },
 
+        openBackfill(source) {
+            this.backfillSource = source;
+            this.backfillDays = 30;
+            this.feedback = { message: '', type: '' };
+        },
+
+        closeBackfill() {
+            this.backfillSource = null;
+            this.backfillDays = 30;
+        },
+
+        validBackfillDays() {
+            const days = Number(this.backfillDays);
+            return Number.isInteger(days) && days >= 1 && days <= 365;
+        },
+
+        async runBackfill() {
+            if (!this.backfillSource || !this.validBackfillDays()) return;
+            const source = this.backfillSource;
+            const days = Number(this.backfillDays);
+            this.closeBackfill();
+            await this.fetchSource(source, days);
+        },
+
         async loadImportHistory(source) {
             this.historySource = source;
             this.importHistory = [];
diff --git a/docs/development/roadmap.md b/docs/development/roadmap.md
index b5900b9..2b402de 100644
--- a/docs/development/roadmap.md
+++ b/docs/development/roadmap.md
@@ -29,6 +29,7 @@ Recently improved:
 - Mail source import history is visible in the Mail Sources UI.
 - Individual mail sources can be manually imported from the Mail Sources UI.
 - Import-history rows include sanitized per-attachment outcomes and imported report IDs.
+- Mail source backfills can be launched from the UI with configurable search windows.
 - The current Alpine-based UI is allowed by CSP and renders dynamic tables in real browsers.
 
 Implementation note:
@@ -39,7 +40,6 @@ Implementation note:
 Objective: make mailbox imports auditable and make report totals trustworthy.
 
 Priority tasks:
-- Add mailbox search controls for date-range backfills.
 - Report duplicate skips separately from parse failures.
 - Improve source rollups so a source IP tracks pass/fail counts over time.
 
diff --git a/docs/milestones.md b/docs/milestones.md
index 3cc882e..c395481 100644
--- a/docs/milestones.md
+++ b/docs/milestones.md
@@ -64,10 +64,10 @@ Recently delivered:
 - Mail source import history is now visible from the Mail Sources UI.
 - A single mail source can be manually imported from the Mail Sources UI, with the result recorded in import history.
 - Import history now includes per-attachment details for imported reports, duplicates, parse errors, unsupported attachments, and imported report IDs.
+- Mail sources can be backfilled from the UI with 7-day, 30-day, 90-day, or custom search windows.
 - The current Alpine-based UI can run under the configured CSP, so dynamic tables render in real browsers.
 
 Next tasks:
-- Add mailbox search controls for date range/backfill without requiring code changes.
 - Improve source aggregation so each sender IP keeps pass/fail totals instead of only the latest result.
 
 Exit criteria:
diff --git a/docs/todo.md b/docs/todo.md
index 7022883..34326e8 100644
--- a/docs/todo.md
+++ b/docs/todo.md
@@ -93,7 +93,7 @@ This file tracks the specific implementation tasks for each milestone of the DMA
 - [x] Show recent import history in the Mail Sources UI
 - [x] Add manual import trigger per mail source
 - [x] Add per-import result details for duplicates, parse failures, unsupported attachments, and imported report IDs
-- [ ] Add retry/backfill controls per mail source
+- [x] Add retry/backfill controls per mail source
 
 ## Milestone 3: Database Integration