Block spam form submissions without using a CAPTCHA

flowchart TD trig>"form submitted on website"]:::trig s0["check hidden honeypot field"]:::task s1["check submission timing"]:::task s2["check email domain"]:::task trig --> s0 s0 --> s1 s1 --> s2 gx{"× submission looks like spam"}:::gate s2 --> gx p00["forward to inbox or crm"]:::task gx -->|"legitimate"| p00 p10["discard silently"]:::task gx -->|"spam"| p10 p00 --> out p10 --> out out[/"clean submissions with spam filtered"/]:::out pay{{"less spam without annoying real visitors"}}:::pay out --> pay classDef task fill:#e7f6fe,stroke:#34b8f0,color:#2c2a29 classDef svc fill:#f6f8fa,stroke:#7c8795,color:#2c2a29 classDef mi fill:#e7f6fe,stroke:#0079a8,color:#2c2a29,stroke-width:2px classDef human fill:#fff,stroke:#0079a8,color:#0079a8 classDef store fill:#f6f8fa,stroke:#0079a8,color:#2c2a29 classDef trig fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigtime fill:#00a4eb,stroke:#0079a8,color:#fff,font-weight:bold classDef trigdata fill:#8ad4f5,stroke:#0079a8,color:#06314c,font-weight:bold classDef gate fill:#fff,stroke:#e8a23d,color:#6b4708,font-weight:bold classDef out fill:#1f9d6b,stroke:#167a53,color:#fff,font-weight:bold classDef pay fill:#06314c,stroke:#021f33,color:#fff