Here are 20 AI content detection tools that can detect AI writing.

Artificial intelligence refers to the simulation of human intelligence processes by machines, especially computer systems. These processes include learning, reasoning, problem-solving, perception, and language understanding. AI enables machines to perform tasks that typically require human intelligence, such as visual perception, speech recognition, decision-making, and language translation.

1. Originality. ai

2. Writer. com

3. Willieai. com

4. GPTZero

5. ParaphrasingTool. ai

6. Winston AI

7. Copyleaks

8. Content at Scale

9. AI Text Classifier (OpenAI)

10. Grammarly

11. Quillbot

12. Textio

13. Articoolo

14. Zest AI

15. Textio

16. Yseop

17. Wordsmith

18. Hugging Face

19. Google Cloud Natural Language API

20. Amazon Comprehend

Bonus ZeroGpt

These tools use machine learning and natural language processing techniques to detect AI-generated content. They can analyze text for AI and plagiarism, and some can even detect the percentage of AI-generated content in an article. 

Some of these tools are free, while others require a subscription or a one-time payment. However, it's important to note that AI detectors can never guarantee 100% accuracy, and there is always a small risk of false positives. 

Therefore, these tools should not be relied upon to provide absolute proof that a text is or isn't AI-generated.