AI Productivity2025
ColdSend AI
Cold email at scale that actually reads like one human wrote it to another. Because one human did — your résumé.
- role
- Solo build · Open source
- timeline
- 3 weeks
- year
- 2025
01 · Problem
What was broken
Mass cold-email tools personalize at the {{firstName}} level. Recipients see through it. Open rates collapse. Recruiters and hiring managers ignore them entirely.
02 · Approach
How I built it
Upload your résumé once. Paste any job description. The OpenAI Responses API extracts the resonance between you and them and writes the email in your voice — referencing one of your real projects, mapped to one of their actual requirements. Bulk-send via Nodemailer.
03 · Stack
What it runs on
Next.js (App Router)OpenAI Responses APIMongoDB + GridFSNodemailerAES-256-GCMshadcn/ui
04 · Outcome
Results that shipped
1
résumé upload · reused across campaigns
CSV
bulk campaigns processed in background
AES-256
encrypted user credentials at rest
OSS
MIT licensed on GitHub
05 · For the engineers
Deep technical breakdown
Click any section below to expand the full engineering write-up.