Run a freemium email newsletter tool with daily send limits

flowchart TD trig>"user submits newsletter design"]:::trig s0(("design and submit email")):::human s1["check plan type"]:::task s2[("check daily send count")]:::store s3[("log send and notify")]:::store trig --> s0 s0 --> s1 s1 --> s2 gx{"× under daily send limit"}:::gate s2 --> gx p00["send via sendgrid"]:::task gx -->|"under limit"| p00 p10["block the send"]:::task gx -->|"limit reached"| p10 jn{"○ log send and notify"}:::gate p00 --> jn p10 --> jn jn --> s3 out[/"newsletter sent within daily limit"/]:::out pay{{"controls sending costs on free tier"}}:::pay s3 --> out 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