Format ChatGPT Chat History (from ZIP download)

format_chatgpt_history.py

# run in extracted folder: python3 format_chatgpt_history.py
import json
from pathlib import Path

def extract_conversations_to_markdown(json_path: Path, output_path: Path):
    with open(json_path, "r", encoding="utf-8") as f:
        conversations = json.load(f)

    def traverse_messages(mapping, node_id):
        messages = []
        node = mapping.get(node_id)
        if not node:
            return messages

        message = node.get("message")
        if message:
            author = message.get("author", {}).get("role")
            content = message.get("content", {})
            parts = content.get("parts")
            if parts and isinstance(parts, list) and parts[0].strip():
                prefix = "User:" if author == "user" else "System:"
                messages.append(f"{prefix} {parts[0].strip()}")

        for child_id in node.get("children", []):
            messages.extend(traverse_messages(mapping, child_id))
        return messages

    output_lines = []
    for conv in conversations:
        title = conv.get("title", "Untitled Conversation")
        mapping = conv.get("mapping", {})
        if not mapping:
            continue
        output_lines.append(f"# {title}\n")
        messages = traverse_messages(mapping, "client-created-root")
        output_lines.extend(messages)
        output_lines.append("\n---\n")

    output_path.write_text("\n\n".join(output_lines), encoding="utf-8")
    print(f"Exported markdown to: {output_path}")

json_file = Path("./conversations.json")
output_file = Path("./conversations.md")
extract_conversations_to_markdown(json_file, output_file)