About OptLint
OptLint exists because SMS registration fails in frustrating ways. A campaign comes back with a one-line reason like MESSAGE_FLOW, you pay another vetting fee, wait several more days, and get a different reason next time. Most rejections trace back to a short list of documented causes that a careful check catches before you submit.
How the rules are built
Every check and explainer is based on published sources: CTIA's Messaging Principles and Best Practices, The Campaign Registry's documentation, carrier codes of conduct, and the public help centers of Twilio, Telnyx, Bandwidth and HighLevel. Each explainer page lists its sources and the date it was last reviewed. Where providers disagree or guidance is unclear, we say so instead of guessing.
Privacy by design
The tools run entirely in your browser, with no account and no tracking. Your campaign text never leaves your device.
Who writes it
OptLint is written and maintained by Adam Hale. It is independent and not affiliated with any messaging provider or carrier.
Corrections
If a rule has changed or something is wrong, please let us know at adam.hale@atomicmail.ai.