diff --git a/src/paimon/CMakeLists.txt b/src/paimon/CMakeLists.txt
index bf57ce9f..051eba32 100644
--- a/src/paimon/CMakeLists.txt
+++ b/src/paimon/CMakeLists.txt
@@ -390,6 +390,7 @@ set(PAIMON_CORE_SRCS
     core/realtime/realtime_append_only_writer.cpp
     core/realtime/realtime_context.cpp
     core/realtime/realtime_context_impl.cpp
+    core/realtime/realtime_primary_key_writer.cpp
     core/postpone/postpone_bucket_writer.cpp
     core/schema/arrow_schema_validator.cpp
     core/schema/schema_manager.cpp
diff --git a/src/paimon/core/realtime/realtime_primary_key_writer.cpp b/src/paimon/core/realtime/realtime_primary_key_writer.cpp
new file mode 100644
index 00000000..61cd1400
--- /dev/null
+++ b/src/paimon/core/realtime/realtime_primary_key_writer.cpp
@@ -0,0 +1,293 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "paimon/core/realtime/realtime_primary_key_writer.h"
+
+#include <limits>
+#include <optional>
+#include <utility>
+#include <vector>
+
+#include "arrow/api.h"
+#include "arrow/c/bridge.h"
+#include "arrow/compute/api.h"
+#include "paimon/common/table/special_fields.h"
+#include "paimon/common/types/row_kind.h"
+#include "paimon/common/utils/arrow/mem_utils.h"
+#include "paimon/common/utils/arrow/status_utils.h"
+#include "paimon/common/utils/checked_cast.h"
+#include "paimon/core/core_options.h"
+#include "paimon/core/io/merged_key_value_record_reader.h"
+#include "paimon/core/mergetree/compact/merge_function.h"
+#include "paimon/core/mergetree/compact/reducer_merge_function_wrapper.h"
+#include "paimon/core/mergetree/merge_tree_writer.h"
+#include "paimon/core/realtime/realtime_context_impl.h"
+#include "paimon/core/realtime/realtime_primary_key_reader.h"
+#include "paimon/core/utils/commit_increment.h"
+#include "paimon/core/utils/primary_key_table_utils.h"
+#include "paimon/macros.h"
+
+namespace paimon {
+
+namespace {
+
+Result<std::shared_ptr<arrow::StructArray>> CreateRealtimePrimaryKeyTransportBatch(
+    std::unique_ptr<RecordBatch>&& batch, const std::shared_ptr<arrow::Schema>& write_schema,
+    const std::shared_ptr<arrow::Schema>& transport_schema,
+    const std::vector<std::string>& trimmed_primary_keys, int64_t first_sequence_number,
+    int64_t first_offset, arrow::MemoryPool* arrow_pool) {
+    PAIMON_ASSIGN_OR_RAISE_FROM_ARROW(
+        std::shared_ptr<arrow::Array> input,
+        arrow::ImportArray(batch->GetData(), arrow::struct_(write_schema->fields())));
+    if (!input || input->type_id() != arrow::Type::STRUCT) {
+        return Status::Invalid("PK real-time write data is not a StructArray");
+    }
+    std::shared_ptr<arrow::StructArray> values = checked_pointer_cast<arrow::StructArray>(input);
+    const int64_t count = values->length();
+    arrow::Int8Builder kinds(arrow_pool);
+    arrow::Int64Builder sequences(arrow_pool);
+    arrow::Int64Builder offsets(arrow_pool);
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(kinds.Reserve(count));
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(sequences.Reserve(count));
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(offsets.Reserve(count));
+    const std::vector<RecordBatch::RowKind>& row_kinds = batch->GetRowKind();
+    for (int64_t row = 0; row < count; ++row) {
+        const RecordBatch::RowKind kind =
+            row_kinds.empty() ? RecordBatch::RowKind::INSERT : row_kinds[row];
+        kinds.UnsafeAppend(static_cast<int8_t>(kind));
+        sequences.UnsafeAppend(first_sequence_number + row);
+        offsets.UnsafeAppend(first_offset + row);
+    }
+    std::shared_ptr<arrow::Array> kind_array;
+    std::shared_ptr<arrow::Array> sequence_array;
+    std::shared_ptr<arrow::Array> offset_array;
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(kinds.Finish(&kind_array));
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(sequences.Finish(&sequence_array));
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(offsets.Finish(&offset_array));
+    arrow::ArrayVector columns = {std::move(kind_array), std::move(sequence_array),
+                                  std::move(offset_array)};
+    columns.insert(columns.end(), values->fields().begin(), values->fields().end());
+    PAIMON_ASSIGN_OR_RAISE_FROM_ARROW(
+        std::shared_ptr<arrow::StructArray> transport,
+        arrow::StructArray::Make(std::move(columns), transport_schema->fields()));
+
+    std::vector<arrow::compute::SortKey> sort_keys;
+    sort_keys.reserve(trimmed_primary_keys.size() + 1);
+    for (const std::string& key : trimmed_primary_keys) {
+        sort_keys.emplace_back(key, arrow::compute::SortOrder::Ascending);
+    }
+    sort_keys.emplace_back(SpecialFields::SequenceNumber().Name(),
+                           arrow::compute::SortOrder::Ascending);
+    arrow::compute::ExecContext context(arrow_pool);
+    arrow::compute::SortOptions options(sort_keys, arrow::compute::NullPlacement::AtStart);
+    PAIMON_ASSIGN_OR_RAISE_FROM_ARROW(
+        arrow::Datum indices,
+        arrow::compute::SortIndices(arrow::Datum(transport), options, &context));
+    PAIMON_ASSIGN_OR_RAISE_FROM_ARROW(
+        arrow::Datum sorted,
+        arrow::compute::Take(arrow::Datum(transport), indices,
+                             arrow::compute::TakeOptions::NoBoundsCheck(), &context));
+    return checked_pointer_cast<arrow::StructArray>(sorted.make_array());
+}
+
+}  // namespace
+
+Result<std::shared_ptr<RealtimePrimaryKeyWriter>> RealtimePrimaryKeyWriter::Create(
+    const std::map<std::string, std::string>& partition, int32_t bucket,
+    const std::shared_ptr<arrow::Schema>& write_schema,
+    const std::shared_ptr<arrow::Schema>& transport_schema,
+    const std::vector<std::string>& trimmed_primary_keys,
+    const std::shared_ptr<FieldsComparator>& key_comparator, const CoreOptions& options,
+    const std::shared_ptr<RealtimeContextImpl>& realtime_context,
+    const RealtimeStoreState& store_state, int64_t restored_max_sequence_number,
+    const std::shared_ptr<MergeTreeWriter>& merge_tree_writer,
+    const std::shared_ptr<MemoryPool>& memory_pool) {
+    if (restored_max_sequence_number < -1 ||
+        restored_max_sequence_number == std::numeric_limits<int64_t>::max()) {
+        return Status::Invalid("PK restored sequence number is invalid");
+    }
+    if (options.GetMergeEngine() != MergeEngine::DEDUPLICATE) {
+        return Status::NotImplemented("PK realtime supports only the DEDUPLICATE merge engine");
+    }
+    PAIMON_RETURN_NOT_OK(RealtimePrimaryKeyLayout::ValidateSchema(transport_schema));
+    arrow::FieldVector key_fields;
+    key_fields.reserve(trimmed_primary_keys.size());
+    for (const std::string& key : trimmed_primary_keys) {
+        std::shared_ptr<arrow::Field> field = write_schema->GetFieldByName(key);
+        if (!field) {
+            return Status::Invalid("PK field is missing from write schema: ", key);
+        }
+        key_fields.push_back(std::move(field));
+    }
+    const RealtimePartitionBucket partition_bucket(partition, bucket);
+    PAIMON_ASSIGN_OR_RAISE(int64_t initial_max_sequence_number,
+                           realtime_context->AdvanceMaterializedMaxSequenceNumber(
+                               partition_bucket, restored_max_sequence_number));
+    return std::shared_ptr<RealtimePrimaryKeyWriter>(new RealtimePrimaryKeyWriter(
+        store_state.store, merge_tree_writer, realtime_context, partition_bucket, write_schema,
+        transport_schema, arrow::schema(std::move(key_fields)), trimmed_primary_keys,
+        key_comparator, options, store_state.initial_offset, initial_max_sequence_number,
+        memory_pool));
+}
+
+RealtimePrimaryKeyWriter::RealtimePrimaryKeyWriter(
+    const std::shared_ptr<RealtimeStore>& realtime_store,
+    const std::shared_ptr<MergeTreeWriter>& merge_tree_writer,
+    const std::shared_ptr<RealtimeContextImpl>& realtime_context,
+    const RealtimePartitionBucket& partition_bucket,
+    const std::shared_ptr<arrow::Schema>& write_schema,
+    const std::shared_ptr<arrow::Schema>& transport_schema,
+    const std::shared_ptr<arrow::Schema>& key_schema,
+    const std::vector<std::string>& trimmed_primary_keys,
+    const std::shared_ptr<FieldsComparator>& key_comparator, const CoreOptions& options,
+    int64_t next_offset, int64_t last_sequence_number,
+    const std::shared_ptr<MemoryPool>& memory_pool)
+    : memory_pool_(memory_pool),
+      arrow_pool_(GetArrowPool(memory_pool)),
+      realtime_store_(realtime_store),
+      merge_tree_writer_(merge_tree_writer),
+      realtime_context_(realtime_context),
+      partition_bucket_(partition_bucket),
+      write_schema_(write_schema),
+      transport_schema_(transport_schema),
+      key_schema_(key_schema),
+      trimmed_primary_keys_(trimmed_primary_keys),
+      key_comparator_(key_comparator),
+      options_(options),
+      next_offset_(next_offset),
+      last_sequence_number_(last_sequence_number) {}
+
+Status RealtimePrimaryKeyWriter::Write(std::unique_ptr<RecordBatch>&& batch) {
+    if (!batch || !batch->GetData()) {
+        return Status::Invalid("PK real-time write batch is null");
+    }
+    const int64_t count = batch->GetData()->length;
+    if (count == 0) {
+        return Status::OK();
+    }
+    const std::vector<RecordBatch::RowKind>& row_kinds = batch->GetRowKind();
+    if (!row_kinds.empty() && static_cast<int64_t>(row_kinds.size()) != count) {
+        return Status::Invalid("PK real-time row-kind count does not match batch row count");
+    }
+    for (RecordBatch::RowKind row_kind : row_kinds) {
+        PAIMON_ASSIGN_OR_RAISE(const RowKind* validated,
+                               RowKind::FromByteValue(static_cast<int8_t>(row_kind)));
+        static_cast<void>(validated);
+    }
+    std::lock_guard<std::mutex> lock(realtime_store_mutex_);
+    if (count > std::numeric_limits<int64_t>::max() - next_offset_) {
+        return Status::Invalid("real-time offset range exceeds INT64_MAX");
+    }
+    // Reserve INT64_MAX as the exhausted sequence-number sentinel.
+    if (last_sequence_number_ >= std::numeric_limits<int64_t>::max() - count) {
+        return Status::Invalid("PK sequence range exceeds INT64_MAX");
+    }
+    const int64_t first_sequence = last_sequence_number_ + 1;
+    PAIMON_ASSIGN_OR_RAISE(
+        std::shared_ptr<arrow::StructArray> transport,
+        CreateRealtimePrimaryKeyTransportBatch(std::move(batch), write_schema_, transport_schema_,
+                                               trimmed_primary_keys_, first_sequence, next_offset_,
+                                               arrow_pool_.get()));
+    auto output = std::make_unique<ArrowArray>();
+    PAIMON_RETURN_NOT_OK_FROM_ARROW(arrow::ExportArray(*transport, output.get()));
+    PAIMON_RETURN_NOT_OK(RetainArrowArrayMemoryPool(output.get(), arrow_pool_));
+    RecordBatchBuilder builder(output.get());
+    PAIMON_ASSIGN_OR_RAISE(std::unique_ptr<RecordBatch> transport_batch, builder.Finish());
+    PAIMON_RETURN_NOT_OK(realtime_store_->Write(RealtimeWriteBatch{
+        std::move(transport_batch), OffsetRange(next_offset_, next_offset_ + count)}));
+    next_offset_ += count;
+    last_sequence_number_ += count;
+    PAIMON_RETURN_NOT_OK(realtime_context_->AdvanceMaterializedMaxSequenceNumber(
+        partition_bucket_, last_sequence_number_));
+    return Status::OK();
+}
+
+Result<CommitIncrement> RealtimePrimaryKeyWriter::PrepareCommit(bool wait_compaction) {
+    std::lock_guard<std::mutex> prepare_lock(prepare_mutex_);
+    std::optional<std::shared_ptr<RealtimeSegmentHandle>> segment;
+    {
+        std::lock_guard<std::mutex> store_lock(realtime_store_mutex_);
+        PAIMON_ASSIGN_OR_RAISE(std::optional<std::shared_ptr<RealtimeSegmentHandle>> sealed,
+                               realtime_store_->SealForCommit());
+        segment = std::move(sealed);
+    }
+    if (segment && !segment.value()) {
+        return Status::Invalid("PK real-time store sealed a null segment");
+    }
+    std::optional<OffsetRange> sealed_range;
+    if (segment) {
+        sealed_range = segment.value()->GetOffsetRange();
+        if (sealed_range->begin < 0 || sealed_range->end < sealed_range->begin) {
+            return Status::Invalid("PK real-time store returned an invalid sealed offset range");
+        }
+        PAIMON_RETURN_NOT_OK(FlushSegment(segment.value(), sealed_range.value()));
+    }
+    PAIMON_ASSIGN_OR_RAISE(CommitIncrement increment,
+                           merge_tree_writer_->PrepareCommit(wait_compaction));
+    if (segment) {
+        increment.SetRealtimeOffsetRange(sealed_range.value());
+    }
+    return increment;
+}
+
+Status RealtimePrimaryKeyWriter::FlushSegment(const std::shared_ptr<RealtimeSegmentHandle>& segment,
+                                              const OffsetRange& sealed_offsets) {
+    PAIMON_ASSIGN_OR_RAISE(std::vector<std::unique_ptr<BatchReader>> readers,
+                           realtime_store_->CreateCommitReaders(segment));
+    PAIMON_ASSIGN_OR_RAISE(
+        std::vector<std::unique_ptr<KeyValueRecordReader>> realtime_primary_key_readers,
+        RealtimePrimaryKeyReaderFactory::CreateForCommit(std::move(readers), transport_schema_,
+                                                         sealed_offsets, key_schema_, write_schema_,
+                                                         memory_pool_));
+    std::vector<std::unique_ptr<KeyValueRecordReader>> sorted_readers;
+    sorted_readers.reserve(realtime_primary_key_readers.size());
+    for (std::unique_ptr<KeyValueRecordReader>& realtime_primary_key_reader :
+         realtime_primary_key_readers) {
+        PAIMON_ASSIGN_OR_RAISE(std::unique_ptr<MergeFunction> merge_function,
+                               PrimaryKeyTableUtils::CreateMergeFunction(
+                                   write_schema_, trimmed_primary_keys_, options_, memory_pool_));
+        sorted_readers.push_back(std::make_unique<MergedKeyValueRecordReader>(
+            std::move(realtime_primary_key_reader), key_comparator_,
+            std::make_shared<ReducerMergeFunctionWrapper>(std::move(merge_function))));
+    }
+    return merge_tree_writer_->WriteSortedReadersToFiles(std::move(sorted_readers));
+}
+
+Status RealtimePrimaryKeyWriter::Compact(bool) {
+    return Status::Invalid("PK real-time write does not support explicit compaction");
+}
+uint64_t RealtimePrimaryKeyWriter::GetMemoryUsage() const {
+    return realtime_store_->GetMemoryUsage();
+}
+Status RealtimePrimaryKeyWriter::FlushMemory() {
+    return Status::OK();
+}
+Result<bool> RealtimePrimaryKeyWriter::CompactNotCompleted() {
+    return merge_tree_writer_->CompactNotCompleted();
+}
+Status RealtimePrimaryKeyWriter::Sync() {
+    return merge_tree_writer_->Sync();
+}
+Status RealtimePrimaryKeyWriter::Close() {
+    return merge_tree_writer_->Close();
+}
+std::shared_ptr<Metrics> RealtimePrimaryKeyWriter::GetMetrics() const {
+    return merge_tree_writer_->GetMetrics();
+}
+
+}  // namespace paimon
diff --git a/src/paimon/core/realtime/realtime_primary_key_writer.h b/src/paimon/core/realtime/realtime_primary_key_writer.h
new file mode 100644
index 00000000..cdd3d889
--- /dev/null
+++ b/src/paimon/core/realtime/realtime_primary_key_writer.h
@@ -0,0 +1,105 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <map>
+#include <memory>
+#include <mutex>
+#include <string>
+#include <vector>
+
+#include "paimon/core/core_options.h"
+#include "paimon/core/utils/batch_writer.h"
+#include "paimon/realtime/realtime_context.h"
+#include "paimon/realtime/realtime_store.h"
+
+namespace arrow {
+class MemoryPool;
+class Schema;
+}  // namespace arrow
+
+namespace paimon {
+
+class MemoryPool;
+class MergeTreeWriter;
+class FieldsComparator;
+class RealtimeContextImpl;
+struct RealtimeStoreState;
+
+class RealtimePrimaryKeyWriter final : public BatchWriter {
+ public:
+    static Result<std::shared_ptr<RealtimePrimaryKeyWriter>> Create(
+        const std::map<std::string, std::string>& partition, int32_t bucket,
+        const std::shared_ptr<arrow::Schema>& write_schema,
+        const std::shared_ptr<arrow::Schema>& transport_schema,
+        const std::vector<std::string>& trimmed_primary_keys,
+        const std::shared_ptr<FieldsComparator>& key_comparator, const CoreOptions& options,
+        const std::shared_ptr<RealtimeContextImpl>& realtime_context,
+        const RealtimeStoreState& store_state, int64_t restored_max_sequence_number,
+        const std::shared_ptr<MergeTreeWriter>& merge_tree_writer,
+        const std::shared_ptr<MemoryPool>& memory_pool);
+
+    Status Write(std::unique_ptr<RecordBatch>&& batch) override;
+    Result<CommitIncrement> PrepareCommit(bool wait_compaction) override;
+    Status Compact(bool full_compaction) override;
+    uint64_t GetMemoryUsage() const override;
+    Status FlushMemory() override;
+    Result<bool> CompactNotCompleted() override;
+    Status Sync() override;
+    Status Close() override;
+    std::shared_ptr<Metrics> GetMetrics() const override;
+
+ private:
+    RealtimePrimaryKeyWriter(const std::shared_ptr<RealtimeStore>& realtime_store,
+                             const std::shared_ptr<MergeTreeWriter>& merge_tree_writer,
+                             const std::shared_ptr<RealtimeContextImpl>& realtime_context,
+                             const RealtimePartitionBucket& partition_bucket,
+                             const std::shared_ptr<arrow::Schema>& write_schema,
+                             const std::shared_ptr<arrow::Schema>& transport_schema,
+                             const std::shared_ptr<arrow::Schema>& key_schema,
+                             const std::vector<std::string>& trimmed_primary_keys,
+                             const std::shared_ptr<FieldsComparator>& key_comparator,
+                             const CoreOptions& options, int64_t next_offset,
+                             int64_t last_sequence_number,
+                             const std::shared_ptr<MemoryPool>& memory_pool);
+
+    Status FlushSegment(const std::shared_ptr<RealtimeSegmentHandle>& segment,
+                        const OffsetRange& sealed_offsets);
+
+    std::shared_ptr<MemoryPool> memory_pool_;
+    std::shared_ptr<arrow::MemoryPool> arrow_pool_;
+    std::shared_ptr<RealtimeStore> realtime_store_;
+    std::shared_ptr<MergeTreeWriter> merge_tree_writer_;
+    std::shared_ptr<RealtimeContextImpl> realtime_context_;
+    RealtimePartitionBucket partition_bucket_;
+    std::shared_ptr<arrow::Schema> write_schema_;
+    std::shared_ptr<arrow::Schema> transport_schema_;
+    std::shared_ptr<arrow::Schema> key_schema_;
+    std::vector<std::string> trimmed_primary_keys_;
+    std::shared_ptr<FieldsComparator> key_comparator_;
+    CoreOptions options_;
+    int64_t next_offset_;
+    int64_t last_sequence_number_;
+    std::mutex realtime_store_mutex_;
+    std::mutex prepare_mutex_;
+};
+
+}  // namespace paimon