I built a free AI text humanizer with dual-engine fallback

Description and use

The author built a free AI text humanizer with a dual-engine fallback to avoid rate limits and hidden charges, adding a strict daily usage cap and bot protection.

Problem

Free AI tools often impose hidden charges after a limited word count, and rate limits can disrupt service reliability.

Outcome

The dual-engine PHP implementation provides uninterrupted humanization service with a daily limit to mitigate abuse, while bundling additional webmaster tools for broader utility.

Workflow

• 1. User visits sitetoolsbox.com
• 2. Navigates to the AI section
• 3. Inputs text to be humanized
• 4. The system queries OpenRouter; if rate‑limited, falls back to SiliconFlow
• 5. Returns humanized text to the user

Evidence

I got tired of "free" AI tools that actually charge you after 200 words.

Source

It's a dual-engine setup (OpenRouter + SiliconFlow) written in pure PHP so it shouldn't crash when the API gets rate-limited.

Source

I also added a strict daily limit (5 uses per IP) because a botnet attacked my endpoint 50 times right after I launched it.

Source