diff --git a/examples/inference/gpt/gpt_dynamic_inference.py b/examples/inference/gpt/gpt_dynamic_inference.py
index 2582f57e13e..55979845512 100644
--- a/examples/inference/gpt/gpt_dynamic_inference.py
+++ b/examples/inference/gpt/gpt_dynamic_inference.py
@@ -435,6 +435,7 @@ def escape_str(s):
             print(f' Saving results to {args.output_path}')
             with open(args.output_path, "w") as fp:
                 json.dump(json_results, fp, indent=1)
+                fp.write("\n")  # End file in newline
 
         # Timing results.
         stats = torch.cuda.memory_stats()
diff --git a/examples/inference/gpt/gpt_dynamic_inference_with_coordinator.py b/examples/inference/gpt/gpt_dynamic_inference_with_coordinator.py
index 536f533eccd..072239c0ab3 100644
--- a/examples/inference/gpt/gpt_dynamic_inference_with_coordinator.py
+++ b/examples/inference/gpt/gpt_dynamic_inference_with_coordinator.py
@@ -154,6 +154,7 @@ async def main(
                 json_results = throughput_dict
             with open(args.output_path, "w") as fp:
                 json.dump(json_results, fp, indent=4)
+                fp.write("\n")  # End file in newline
         else:
             print("Results:")
             unique_prompt_map = defaultdict(list)
diff --git a/examples/inference/gpt/gpt_static_inference.py b/examples/inference/gpt/gpt_static_inference.py
index 17cf7c53b05..4c820fd06a3 100644
--- a/examples/inference/gpt/gpt_static_inference.py
+++ b/examples/inference/gpt/gpt_static_inference.py
@@ -188,6 +188,7 @@ def main():
 
         with open(args.output_path, 'w') as f:
             json.dump(results_output, f)
+            f.write('\n')  # End file in newline
 
     # Print unique prompts + outputs.
     if torch.distributed.get_rank() == 0:
diff --git a/examples/multimodal/evaluation/evaluate_ai2d.py b/examples/multimodal/evaluation/evaluate_ai2d.py
index 01ff4e8f48f..8f98b8e871b 100644
--- a/examples/multimodal/evaluation/evaluate_ai2d.py
+++ b/examples/multimodal/evaluation/evaluate_ai2d.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -31,6 +33,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_chartqa.py b/examples/multimodal/evaluation/evaluate_chartqa.py
index 7fbddf0204f..8c69e7b2086 100644
--- a/examples/multimodal/evaluation/evaluate_chartqa.py
+++ b/examples/multimodal/evaluation/evaluate_chartqa.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -28,6 +30,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_coco.py b/examples/multimodal/evaluation/evaluate_coco.py
index 50031f3a5c4..1d92cc3c5f6 100644
--- a/examples/multimodal/evaluation/evaluate_coco.py
+++ b/examples/multimodal/evaluation/evaluate_coco.py
@@ -33,6 +33,7 @@ def convert_to_coco_format(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_infovqa.py b/examples/multimodal/evaluation/evaluate_infovqa.py
index ca327ab2b0d..87994ec4952 100644
--- a/examples/multimodal/evaluation/evaluate_infovqa.py
+++ b/examples/multimodal/evaluation/evaluate_infovqa.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -28,6 +30,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_mathvista.py b/examples/multimodal/evaluation/evaluate_mathvista.py
index cb6b2ebd236..c49822006ee 100644
--- a/examples/multimodal/evaluation/evaluate_mathvista.py
+++ b/examples/multimodal/evaluation/evaluate_mathvista.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 import re
@@ -29,6 +31,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_mmmu.py b/examples/multimodal/evaluation/evaluate_mmmu.py
index 2bdc2ebbdc5..cbe7b21980f 100644
--- a/examples/multimodal/evaluation/evaluate_mmmu.py
+++ b/examples/multimodal/evaluation/evaluate_mmmu.py
@@ -80,6 +80,7 @@ def convert_to_mmmu_format(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(output, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_ocrbench.py b/examples/multimodal/evaluation/evaluate_ocrbench.py
index b43d195494f..267ec4cd96c 100644
--- a/examples/multimodal/evaluation/evaluate_ocrbench.py
+++ b/examples/multimodal/evaluation/evaluate_ocrbench.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -26,6 +28,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_ocrbench_v2.py b/examples/multimodal/evaluation/evaluate_ocrbench_v2.py
index 660f4ecbea7..737eafc7dd3 100644
--- a/examples/multimodal/evaluation/evaluate_ocrbench_v2.py
+++ b/examples/multimodal/evaluation/evaluate_ocrbench_v2.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 import subprocess
@@ -30,6 +32,7 @@ def convert_to_ocrbench_v2_format(input_path, groundtruth_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(output, output_file)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_rd_tablebench.py b/examples/multimodal/evaluation/evaluate_rd_tablebench.py
index 588c1927799..9b17e0b56cb 100644
--- a/examples/multimodal/evaluation/evaluate_rd_tablebench.py
+++ b/examples/multimodal/evaluation/evaluate_rd_tablebench.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import glob
 import json
@@ -35,6 +37,7 @@ def convert_to_rdtablebench_format(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(output, output_file)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_realworldqa.py b/examples/multimodal/evaluation/evaluate_realworldqa.py
index 6ef78d047e3..9a40e9bbc5f 100644
--- a/examples/multimodal/evaluation/evaluate_realworldqa.py
+++ b/examples/multimodal/evaluation/evaluate_realworldqa.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -25,6 +27,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_spdocvqa.py b/examples/multimodal/evaluation/evaluate_spdocvqa.py
index 57a5c237af5..1f6862dd675 100644
--- a/examples/multimodal/evaluation/evaluate_spdocvqa.py
+++ b/examples/multimodal/evaluation/evaluate_spdocvqa.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -28,6 +30,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_textvqa.py b/examples/multimodal/evaluation/evaluate_textvqa.py
index e3647db3a24..65e31dc9660 100644
--- a/examples/multimodal/evaluation/evaluate_textvqa.py
+++ b/examples/multimodal/evaluation/evaluate_textvqa.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -31,6 +33,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_video_motionbench.py b/examples/multimodal/evaluation/evaluate_video_motionbench.py
index 7d6db0354e2..a858d0bad36 100644
--- a/examples/multimodal/evaluation/evaluate_video_motionbench.py
+++ b/examples/multimodal/evaluation/evaluate_video_motionbench.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -26,6 +28,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_video_mvbench.py b/examples/multimodal/evaluation/evaluate_video_mvbench.py
index 0efcdbedb14..3a0f2fd8618 100644
--- a/examples/multimodal/evaluation/evaluate_video_mvbench.py
+++ b/examples/multimodal/evaluation/evaluate_video_mvbench.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -25,6 +27,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_video_phys_game_bench.py b/examples/multimodal/evaluation/evaluate_video_phys_game_bench.py
index feb4c558120..22caec5d548 100644
--- a/examples/multimodal/evaluation/evaluate_video_phys_game_bench.py
+++ b/examples/multimodal/evaluation/evaluate_video_phys_game_bench.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 
@@ -24,6 +26,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/evaluate_vqav2.py b/examples/multimodal/evaluation/evaluate_vqav2.py
index 9789e30379b..156f115db5a 100644
--- a/examples/multimodal/evaluation/evaluate_vqav2.py
+++ b/examples/multimodal/evaluation/evaluate_vqav2.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import argparse
 import json
 from typing import List
@@ -78,6 +80,7 @@ def merge_input_files(input_path):
 
     with open(output_file_path, "w") as output_file:
         json.dump(results, output_file, indent=4, sort_keys=True)
+        output_file.write("\n")  # End file in newline
 
     return output_file_path
 
diff --git a/examples/multimodal/evaluation/mmmu_utils.py b/examples/multimodal/evaluation/mmmu_utils.py
index 61a876b067b..d7cf2e5b26e 100644
--- a/examples/multimodal/evaluation/mmmu_utils.py
+++ b/examples/multimodal/evaluation/mmmu_utils.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 # The following code is adapted from
 # https://github.com/MMMU-Benchmark/MMMU/blob/main/mmmu/utils/data_utils.py,
 # which is licensed under the Apache License 2.0. More details on the license can be
@@ -526,10 +528,11 @@ def mmmu_main_eval(output_dict, task_cfg):
             )
             eval_output_dict[res['question_id']] = pred_ans
 
-    json.dump(eval_output_dict, open("validation_mmmu_iter6000_merged.0.53.sorted.json", "w"), indent=4, sort_keys=True)
-
+    with open("validation_mmmu_iter6000_merged.0.53.sorted.json", "w") as f:
+        json.dump(eval_output_dict, f, indent=4, sort_keys=True)
+        f.write("\n")  # End file in newline
 
     x = mmmu_main_eval(eval_output_dict,
                    task_cfg=tasks['mmmu'])
 
-    print(x)
\ No newline at end of file
+    print(x)
diff --git a/megatron/core/config_logger.py b/megatron/core/config_logger.py
index bee2be09205..c21535e05e8 100644
--- a/megatron/core/config_logger.py
+++ b/megatron/core/config_logger.py
@@ -121,6 +121,7 @@ def log_config_to_disk(config, dict_data, prefix='', rank_str=''):
     else:
         with open(f'{path}.json', 'w') as fp:
             json.dump(dict_data, fp, cls=JSONEncoderWithMcoreTypes)
+            fp.write('\n')  # End file in newline
 
 
 __all__ = ['has_config_logger_enabled', 'log_config_to_disk']
diff --git a/megatron/core/dist_checkpointing/core.py b/megatron/core/dist_checkpointing/core.py
index 164aec1ca52..42aba89ea2d 100644
--- a/megatron/core/dist_checkpointing/core.py
+++ b/megatron/core/dist_checkpointing/core.py
@@ -88,6 +88,8 @@ def save_config(config: CheckpointingConfig, checkpoint_dir: str):
         msc = MultiStorageClientFeature.import_package()
         with msc.open(config_path, 'w') as f:
             json.dump(asdict(config), f)
+            f.write('\n')  # End file in newline
     else:
         with open(config_path, 'w') as f:
             json.dump(asdict(config), f)
+            f.write('\n')  # End file in newline
diff --git a/megatron/core/tokenizers/megatron_tokenizer.py b/megatron/core/tokenizers/megatron_tokenizer.py
index 31694d91af0..dd5f1d1ab41 100644
--- a/megatron/core/tokenizers/megatron_tokenizer.py
+++ b/megatron/core/tokenizers/megatron_tokenizer.py
@@ -163,6 +163,7 @@ def write_metadata(
 
             with open(metadata_path, "w") as f:
                 json.dump(metadata, f)
+                f.write("\n")  # End file in newline
 
             logger.info(f"Metadata file was sucessfully saved: {metadata_path}.")
 
diff --git a/megatron/rl/rl_utils.py b/megatron/rl/rl_utils.py
index 46436add1da..55cd1b9fe54 100644
--- a/megatron/rl/rl_utils.py
+++ b/megatron/rl/rl_utils.py
@@ -574,6 +574,7 @@ def get_environment_rollouts(
             'w',
         ) as f:
             json.dump([[r.model_dump() for r in group] for group in rollouts], f)
+            f.write('\n')  # End file in newline
 
     return rollouts
 
@@ -1601,6 +1602,7 @@ def evaluate_and_print_results_rl(
                     'w',
                 ) as f:
                     json.dump([[r.model_dump() for r in group] for group in dp_eval_results], f)
+                    f.write('\n')  # End file in newline
 
 
 def calculate_grpo_loss(
diff --git a/megatron/training/ft_integration.py b/megatron/training/ft_integration.py
index f3532e75639..e5782811a5d 100644
--- a/megatron/training/ft_integration.py
+++ b/megatron/training/ft_integration.py
@@ -238,6 +238,7 @@ def _update_timeouts(selected_sections, calc_out_of_section):
         ft_state = rmon_cli.state_dict()
         with open(_ft_state_path, "w") as f:
             json.dump(ft_state, f)
+            f.write("\n")  # End file in newline
         print_rank_0(f"FT: updated timeouts saved to {_ft_state_path}. {rmon_cli.section_timeouts}")
 
 
diff --git a/tests/functional_tests/python_test_utils/compute_golden_statistics.py b/tests/functional_tests/python_test_utils/compute_golden_statistics.py
index d4863fa9476..ecc159c755f 100644
--- a/tests/functional_tests/python_test_utils/compute_golden_statistics.py
+++ b/tests/functional_tests/python_test_utils/compute_golden_statistics.py
@@ -796,6 +796,7 @@ def main():
 
     with open(output_path, 'w') as f:
         json.dump(output, f, indent=2)
+        f.write('\n')  # End file in newline
 
     logger.info(f"Statistics written to {args.output}")
 
diff --git a/tests/functional_tests/python_test_utils/get_test_results_from_tensorboard_logs.py b/tests/functional_tests/python_test_utils/get_test_results_from_tensorboard_logs.py
index 7b74a6879ad..1da044f07b0 100644
--- a/tests/functional_tests/python_test_utils/get_test_results_from_tensorboard_logs.py
+++ b/tests/functional_tests/python_test_utils/get_test_results_from_tensorboard_logs.py
@@ -1,3 +1,5 @@
+# Copyright (c) 2023-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+
 import os
 
 os.environ["OPENBLAS_NUM_THREADS"] = "1"
@@ -76,6 +78,7 @@ def collect_train_test_metrics(
                 fh,
                 indent=4,
             )
+            fh.write("\n")  # End file in newline
 
 
 if __name__ == "__main__":
diff --git a/tests/functional_tests/test_cases/common/moe_perf/__main__.py b/tests/functional_tests/test_cases/common/moe_perf/__main__.py
index ace44c7ca4f..9a89bdef5fb 100644
--- a/tests/functional_tests/test_cases/common/moe_perf/__main__.py
+++ b/tests/functional_tests/test_cases/common/moe_perf/__main__.py
@@ -106,7 +106,7 @@ def _persist_baselines(data: Dict[str, Dict[str, float]]) -> None:
     BASELINES_PATH.parent.mkdir(parents=True, exist_ok=True)
     with BASELINES_PATH.open("w", encoding="utf-8") as fh:
         json.dump(data, fh, indent=2, sort_keys=True)
-        fh.write("\n")
+        fh.write("\n")  # End file in newline
 
 
 def _serialize_metrics(metrics: Dict[str, float]) -> Dict[str, float]:
diff --git a/tools/build_sequences_per_dataset.py b/tools/build_sequences_per_dataset.py
index e2787dd6434..cd955c2f285 100644
--- a/tools/build_sequences_per_dataset.py
+++ b/tools/build_sequences_per_dataset.py
@@ -113,5 +113,6 @@ def build_sequences_per_dataset(args):
 
     with open(args.path_to_sequences_per_dataset_json, "w") as f:
         json.dump(sequence_count_dict, f)
+        f.write("\n")  # End file in newline
 
-    print(f"Done! Saving --path-to-sequences-per-dataset file to {args.path_to_sequences_per_dataset_json}")
\ No newline at end of file
+    print(f"Done! Saving --path-to-sequences-per-dataset file to {args.path_to_sequences_per_dataset_json}")
diff --git a/tools/checkpoint/checkpoint_inspector.py b/tools/checkpoint/checkpoint_inspector.py
index 3d03f4db959..a5e98bbeb53 100644
--- a/tools/checkpoint/checkpoint_inspector.py
+++ b/tools/checkpoint/checkpoint_inspector.py
@@ -967,6 +967,7 @@ def print_torch_dcp_in_json(torch_dcp_dir, model_weight_prefix="model.module"):
         json_file_path = os.path.join(torch_dcp_dir, "param_to_param_group_map.json")
         with open(json_file_path, "w") as json_file:
             json.dump(serializable_dict, json_file, indent=2)
+            json_file.write("\n")  # End file in newline
         click.echo(f"Saved converted param_to_param_group_map to: {json_file_path}")
 
 
diff --git a/tools/checkpoint/loader_llama_mistral.py b/tools/checkpoint/loader_llama_mistral.py
index 3c3a1b610a1..287e3045305 100644
--- a/tools/checkpoint/loader_llama_mistral.py
+++ b/tools/checkpoint/loader_llama_mistral.py
@@ -70,6 +70,7 @@ def read_json(path):
 def write_json(text, path):
     with open(path, "w") as f:
         json.dump(text, f)
+        f.write("\n")  # End file in newline
 
 
 # This conversion is adapted from