diff --git a/core/app/Ingest/DueAtParser.php b/core/app/Ingest/DueAtParser.php
new file mode 100644
index 0000000..af08256
--- /dev/null
+++ b/core/app/Ingest/DueAtParser.php
@@ -0,0 +1,57 @@
+<?php
+
+namespace App\Ingest;
+
+use App\Scheduling\DueResolver;
+use Carbon\CarbonImmutable;
+use InvalidArgumentException;
+
+final class DueAtParser
+{
+    private const DATE = '/^(\d{4})-(\d{2})-(\d{2})$/';
+    private const LOCAL_DATETIME = '/^(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2})(?::(\d{2}))?$/';
+    private const FIXED_DATETIME = '/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}(?::\d{2})?(Z|[+-]\d{2}:\d{2})$/';
+
+    public static function parse(string $raw): ParsedDue
+    {
+        if (preg_match(self::DATE, $raw, $m)) {
+            self::assertDate((int) $m[1], (int) $m[2], (int) $m[3], $raw);
+
+            return ParsedDue::local($raw, DueResolver::WHOLE_DAY);
+        }
+
+        if (preg_match(self::LOCAL_DATETIME, $raw, $m)) {
+            self::assertDate((int) $m[1], (int) $m[2], (int) $m[3], $raw);
+            self::assertTime((int) $m[4], (int) $m[5], (int) ($m[6] ?? 0), $raw);
+
+            return ParsedDue::local(
+                sprintf('%s-%s-%s', $m[1], $m[2], $m[3]),
+                sprintf('%s:%s:%02d', $m[4], $m[5], (int) ($m[6] ?? 0)),
+            );
+        }
+
+        if (preg_match(self::FIXED_DATETIME, $raw)) {
+            try {
+                return ParsedDue::fixed(CarbonImmutable::parse($raw));
+            } catch (\Throwable $e) {
+                throw new InvalidArgumentException("due_at: невалидная дата-время «{$raw}»", 0, $e);
+            }
+        }
+
+        throw new InvalidArgumentException("due_at: ожидается YYYY-MM-DD, YYYY-MM-DDTHH:MM или дата-время со смещением, получено «{$raw}»");
+    }
+
+    private static function assertDate(int $y, int $m, int $d, string $raw): void
+    {
+        if (! checkdate($m, $d, $y)) {
+            throw new InvalidArgumentException("due_at: несуществующая дата «{$raw}»");
+        }
+    }
+
+    private static function assertTime(int $h, int $i, int $s, string $raw): void
+    {
+        if ($h > 23 || $i > 59 || $s > 59) {
+            throw new InvalidArgumentException("due_at: невалидное время «{$raw}»");
+        }
+    }
+}
diff --git a/core/app/Ingest/EventUpserter.php b/core/app/Ingest/EventUpserter.php
new file mode 100644
index 0000000..464a732
--- /dev/null
+++ b/core/app/Ingest/EventUpserter.php
@@ -0,0 +1,118 @@
+<?php
+
+namespace App\Ingest;
+
+use App\Enums\AfterDue;
+use App\Enums\ChannelType;
+use App\Enums\EventState;
+use App\Models\Event;
+use App\Models\Source;
+use App\Models\User;
+use App\Scheduling\StateResolver;
+use Carbon\CarbonImmutable;
+use Illuminate\Support\Facades\DB;
+
+final class EventUpserter
+{
+    public function __construct(private readonly StateResolver $states) {}
+
+    /**
+     * @param list<array{user:string,source_ref:string,topic?:string,due_at:string,fire_at:string,after_due:string,payload:array}> $items
+     * @return list<array{source_ref:string,topic:string,id:int,state:string}>
+     */
+    public function upsert(Source $source, array $items): array
+    {
+        return DB::transaction(function () use ($source, $items) {
+            $out = [];
+            foreach ($items as $item) {
+                $event = $this->upsertOne($source, $item);
+                $out[] = [
+                    'source_ref' => $event->source_ref,
+                    'topic' => $event->topic,
+                    'id' => $event->id,
+                    'state' => $event->state->value,
+                ];
+            }
+
+            return $out;
+        });
+    }
+
+    public function withdraw(Source $source, string $sourceRef, string $topic): bool
+    {
+        $event = $this->find($source, $sourceRef, $topic);
+        if ($event === null) {
+            return false;
+        }
+        $event->update(['state' => EventState::Withdrawn]);
+
+        return true;
+    }
+
+    public function find(Source $source, string $sourceRef, string $topic): ?Event
+    {
+        return Event::where('source_id', $source->id)
+            ->where('source_ref', $sourceRef)
+            ->where('topic', $topic)
+            ->first();
+    }
+
+    /** Пользователь по логину; создаётся с поясом по умолчанию и web-каналом. */
+    public function ensureUser(string $login): User
+    {
+        $user = User::firstOrCreate(
+            ['login' => $login],
+            ['tz' => config('hado.default_tz'), 'quiet_start' => '22:00:00', 'quiet_end' => '09:00:00'],
+        );
+        $user->channels()->firstOrCreate(['type' => ChannelType::Web->value], ['config' => [], 'enabled' => true]);
+
+        return $user;
+    }
+
+    private function upsertOne(Source $source, array $item): Event
+    {
+        $user = $this->ensureUser($item['user']);
+        $due = DueAtParser::parse($item['due_at']);
+        $topic = $item['topic'] ?? '';
+        $now = $user->now();
+
+        $attributes = [
+            'user_id' => $user->id,
+            'fire_on' => $item['fire_at'],
+            'after_due' => AfterDue::from($item['after_due']),
+            'payload' => $item['payload'],
+        ] + $due->columns();
+
+        $event = $this->find($source, $item['source_ref'], $topic);
+
+        if ($event === null) {
+            $event = new Event([
+                'source_id' => $source->id,
+                'source_ref' => $item['source_ref'],
+                'topic' => $topic,
+                'state' => EventState::Scheduled,
+                'quiet_until' => $now->subMinute(),
+            ] + $attributes);
+            $event->state = $this->states->resolve($event, $user, $now);
+            $event->save();
+
+            return $event;
+        }
+
+        $dueChanged = ! $due->equals($event);
+        $event->fill($attributes);
+
+        if ($dueChanged) {
+            // Перенос: новая дата — новый заход, даже из терминального состояния.
+            $event->done_at = null;
+            $event->quiet_until = $now->subMinute();
+            $event->state = $this->states->resolve($event, $user, $now);
+        } elseif (! $event->isTerminal()) {
+            $event->state = $this->states->resolve($event, $user, $now);
+        }
+
+        $event->save();
+
+        return $event;
+    }
+}
diff --git a/core/app/Ingest/ParsedDue.php b/core/app/Ingest/ParsedDue.php
new file mode 100644
index 0000000..721c6f3
--- /dev/null
+++ b/core/app/Ingest/ParsedDue.php
@@ -0,0 +1,60 @@
+<?php
+
+namespace App\Ingest;
+
+use App\Enums\DueMode;
+use App\Models\Event;
+use Carbon\CarbonImmutable;
+
+/** Разобранный due_at: tagged union по mode. */
+final class ParsedDue
+{
+    private function __construct(
+        public readonly DueMode $mode,
+        public readonly ?string $date,
+        public readonly ?string $time,
+        public readonly ?CarbonImmutable $instant,
+    ) {}
+
+    public static function local(string $date, string $time): self
+    {
+        return new self(DueMode::Local, $date, $time, null);
+    }
+
+    public static function fixed(CarbonImmutable $instant): self
+    {
+        return new self(DueMode::Fixed, null, null, $instant->utc());
+    }
+
+    /** Календарный день срока в данном поясе, Y-m-d. */
+    public function dayFor(string $tz): string
+    {
+        return match ($this->mode) {
+            DueMode::Local => $this->date,
+            DueMode::Fixed => $this->instant->setTimezone($tz)->format('Y-m-d'),
+        };
+    }
+
+    public function equals(Event $event): bool
+    {
+        if ($event->due_mode !== $this->mode) {
+            return false;
+        }
+
+        return match ($this->mode) {
+            DueMode::Local => $event->due_date->format('Y-m-d') === $this->date && $event->due_time === $this->time,
+            DueMode::Fixed => $event->due_instant->eq($this->instant),
+        };
+    }
+
+    /** @return array<string, mixed> колонки events */
+    public function columns(): array
+    {
+        return [
+            'due_mode' => $this->mode,
+            'due_date' => $this->date,
+            'due_time' => $this->time,
+            'due_instant' => $this->instant,
+        ];
+    }
+}
diff --git a/core/tests/Feature/EventUpserterTest.php b/core/tests/Feature/EventUpserterTest.php
new file mode 100644
index 0000000..14895bc
--- /dev/null
+++ b/core/tests/Feature/EventUpserterTest.php
@@ -0,0 +1,137 @@
+<?php
+
+namespace Tests\Feature;
+
+use App\Enums\ChannelType;
+use App\Enums\EventState;
+use App\Ingest\EventUpserter;
+use App\Models\Event;
+use App\Models\Source;
+use App\Models\User;
+use Carbon\CarbonImmutable;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Tests\TestCase;
+
+class EventUpserterTest extends TestCase
+{
+    use RefreshDatabase;
+
+    private Source $source;
+    private EventUpserter $upserter;
+
+    protected function setUp(): void
+    {
+        parent::setUp();
+        config(['hado.default_tz' => 'America/Montevideo']);
+        CarbonImmutable::setTestNow('2026-09-01T12:00:00-03:00');
+        $this->source = Source::create(['name' => 'docs', 'token_hash' => hash('sha256', 'x')]);
+        $this->upserter = app(EventUpserter::class);
+    }
+
+    protected function tearDown(): void
+    {
+        CarbonImmutable::setTestNow();
+        parent::tearDown();
+    }
+
+    private function item(array $over = []): array
+    {
+        return array_replace([
+            'user' => 'nikita', 'source_ref' => 'document:918', 'topic' => 'expiry',
+            'due_at' => '2026-09-30', 'fire_at' => '2026-08-31', 'after_due' => 'keep',
+            'payload' => ['title' => 'Седула протухает 30 сен'],
+        ], $over);
+    }
+
+    public function test_creates_event_user_and_web_channel_with_computed_state(): void
+    {
+        $result = $this->upserter->upsert($this->source, [$this->item()]);
+
+        $this->assertSame([['source_ref' => 'document:918', 'topic' => 'expiry', 'id' => 1, 'state' => 'preparing']], $result);
+        $user = User::where('login', 'nikita')->firstOrFail();
+        $this->assertSame('America/Montevideo', $user->tz);
+        $this->assertSame(ChannelType::Web, $user->channels()->sole()->type);
+        $event = Event::sole();
+        $this->assertSame(EventState::Preparing, $event->state);
+        $this->assertTrue($event->quiet_until->lt(CarbonImmutable::now()));
+    }
+
+    public function test_same_due_updates_fields_and_keeps_terminal_state(): void
+    {
+        $this->upserter->upsert($this->source, [$this->item()]);
+        Event::sole()->update(['state' => EventState::Done, 'done_at' => now()]);
+
+        $this->upserter->upsert($this->source, [$this->item(['payload' => ['title' => 'Новый заголовок'], 'fire_at' => '2026-09-15'])]);
+
+        $event = Event::sole();
+        $this->assertSame(EventState::Done, $event->state);
+        $this->assertSame('Новый заголовок', $event->payload['title']);
+        $this->assertSame('2026-09-15', $event->fire_on->format('Y-m-d'));
+    }
+
+    public function test_same_due_recomputes_non_terminal_state(): void
+    {
+        $this->upserter->upsert($this->source, [$this->item()]);
+        $this->assertSame(EventState::Preparing, Event::sole()->state);
+
+        $this->upserter->upsert($this->source, [$this->item(['fire_at' => '2026-09-20'])]);
+        $this->assertSame(EventState::Scheduled, Event::sole()->state, 'старт отодвинули в будущее');
+    }
+
+    public function test_new_due_resets_even_from_terminal(): void
+    {
+        $this->upserter->upsert($this->source, [$this->item()]);
+        Event::sole()->update(['state' => EventState::Done, 'done_at' => now(), 'quiet_until' => CarbonImmutable::now()->addDays(3)]);
+
+        $this->upserter->upsert($this->source, [$this->item(['due_at' => '2026-10-15'])]);
+
+        $event = Event::sole();
+        $this->assertSame(EventState::Preparing, $event->state);
+        $this->assertNull($event->done_at);
+        $this->assertTrue($event->quiet_until->lt(CarbonImmutable::now()));
+        $this->assertSame('2026-10-15', $event->due_date->format('Y-m-d'));
+    }
+
+    public function test_reschedule_on_the_day_resets_today_event(): void
+    {
+        // Задокументированное поведение: перенос в день срока сбрасывает состояние.
+        // Поэтому повторяющиеся события кладут период в topic, а не меняют due_at.
+        CarbonImmutable::setTestNow('2026-09-30T10:00:00-03:00');
+        $this->upserter->upsert($this->source, [$this->item()]);
+        $this->assertSame(EventState::Today, Event::sole()->state);
+
+        $this->upserter->upsert($this->source, [$this->item(['due_at' => '2027-09-30', 'fire_at' => '2027-08-31'])]);
+        $this->assertSame(EventState::Scheduled, Event::sole()->state);
+    }
+
+    public function test_occurrences_are_independent_rows(): void
+    {
+        CarbonImmutable::setTestNow('2026-10-05T10:00:00-03:00');
+        $this->upserter->upsert($this->source, [
+            $this->item(['source_ref' => 'rent', 'topic' => 'payment:2026-09', 'due_at' => '2026-09-10', 'fire_at' => '2026-09-10']),
+            $this->item(['source_ref' => 'rent', 'topic' => 'payment:2026-10', 'due_at' => '2026-10-10', 'fire_at' => '2026-10-10']),
+        ]);
+
+        $states = Event::orderBy('topic')->pluck('state')->map->value->all();
+        $this->assertSame(['overdue', 'scheduled'], $states);
+    }
+
+    public function test_fixed_due_is_stored_as_instant(): void
+    {
+        $this->upserter->upsert($this->source, [$this->item(['due_at' => '2026-09-10T08:15+02:00', 'fire_at' => '2026-09-03'])]);
+
+        $event = Event::sole();
+        $this->assertSame('fixed', $event->due_mode->value);
+        $this->assertSame('2026-09-10T06:15:00+00:00', $event->due_instant->utc()->toIso8601String());
+        $this->assertNull($event->due_date);
+    }
+
+    public function test_withdraw_marks_withdrawn_and_reports_missing(): void
+    {
+        $this->upserter->upsert($this->source, [$this->item()]);
+
+        $this->assertTrue($this->upserter->withdraw($this->source, 'document:918', 'expiry'));
+        $this->assertSame(EventState::Withdrawn, Event::sole()->state);
+        $this->assertFalse($this->upserter->withdraw($this->source, 'document:918', 'other'));
+    }
+}
diff --git a/core/tests/Unit/Ingest/DueAtParserTest.php b/core/tests/Unit/Ingest/DueAtParserTest.php
new file mode 100644
index 0000000..335ce9c
--- /dev/null
+++ b/core/tests/Unit/Ingest/DueAtParserTest.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace Tests\Unit\Ingest;
+
+use App\Enums\DueMode;
+use App\Ingest\DueAtParser;
+use InvalidArgumentException;
+use Tests\TestCase; // Laravel TestCase: Eloquent date-casts need the connection grammar even in memory
+
+class DueAtParserTest extends TestCase
+{
+    public function test_date_only_is_whole_day_local(): void
+    {
+        $p = DueAtParser::parse('2026-08-14');
+        $this->assertSame(DueMode::Local, $p->mode);
+        $this->assertSame('2026-08-14', $p->date);
+        $this->assertSame('24:00:00', $p->time);
+        $this->assertNull($p->instant);
+        $this->assertSame('2026-08-14', $p->dayFor('Asia/Shanghai'));
+    }
+
+    public function test_datetime_without_offset_is_local(): void
+    {
+        $p = DueAtParser::parse('2026-09-10T14:00');
+        $this->assertSame(DueMode::Local, $p->mode);
+        $this->assertSame('2026-09-10', $p->date);
+        $this->assertSame('14:00:00', $p->time);
+
+        $this->assertSame('14:05:30', DueAtParser::parse('2026-09-10T14:05:30')->time);
+    }
+
+    public function test_datetime_with_offset_is_fixed(): void
+    {
+        $p = DueAtParser::parse('2026-09-10T08:15+02:00');
+        $this->assertSame(DueMode::Fixed, $p->mode);
+        $this->assertNull($p->date);
+        $this->assertSame('2026-09-10T06:15:00+00:00', $p->instant->utc()->toIso8601String());
+        $this->assertSame('2026-09-10', $p->dayFor('America/Montevideo'));
+        $this->assertSame('2026-09-10', $p->dayFor('Asia/Shanghai'));
+
+        $this->assertSame(DueMode::Fixed, DueAtParser::parse('2026-09-10T06:15:00Z')->mode);
+    }
+
+    public function test_garbage_is_rejected(): void
+    {
+        foreach (['', 'tomorrow', '2026-13-01', '14:00', '2026-09-10 14:00', '2026-09-10T25:00'] as $bad) {
+            try {
+                DueAtParser::parse($bad);
+                $this->fail("accepted: $bad");
+            } catch (InvalidArgumentException) {
+                $this->addToAssertionCount(1);
+            }
+        }
+    }
+}