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Power Pack Email Scorer
x402
Power Pack Email Scorer is a paid API for AI agents from power-pack-x402.fly.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).
Scores an outreach email on multiple quality dimensions and returns improvement suggestions plus a rewritten subject line
Price / call$0.01
Success—
StatusUnknown
How this service works
Score an outreach email on subject quality, body quality, predicted open rate, spam risk, tone, length, personalization, and CTA clarity. Returns top 3 specific improvement suggestions and a stronger rewritten subject line. Useful for sales/marketing/recruiting AI agents that need QA before sending. Powered by Claude Haiku 4.5 with senior-copywriter system prompt.
Output
Returns an ok boolean plus a score object containing numeric/letter ratings for subject quality, body quality, predicted open rate, spam risk, tone, length, personalization, and CTA clarity, along with the top 3 specific actionable improvement suggestions and a rewritten stronger subject line.
Example use cases
Example prompt
“Before I send this cold sales email, can you score it for me? Subject: 'Quick question about your Q4 pipeline' — Body: 'Hi Sarah, I noticed Acme Corp just expanded into EMEA. We help revenue teams like yours hit quota 30% faster. Worth a 15-min call this week?' I want scores on spam risk, open rate, CTA clarity, and your top 3 suggestions to make it better, plus a stronger subject line.”
Technical details
Endpoint
POSThttps://power-pack-x402.fly.dev/api/score-emailWhen to prefer
Choose this endpoint when you need a fast, affordable ($0.01 per call) pre-send QA check on individual outreach emails — especially in sales, marketing, or recruiting workflows where email quality directly affects response rates. Prefer this over generic LLM prompting because it uses a specialized senior-copywriter system prompt and returns structured scores with concrete improvement suggestions, making it easy to programmatically gate or improve emails before delivery.
Side effects
- Missing or empty email content returns an error field with ok: false
- Extremely long email bodies may be truncated or rejected
- Payment not included or insufficient USDC triggers 402 payment required
- Malformed JSON input returns a validation error
- Claude API timeout on the backend returns a 500 error with ok: false
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| properties | string |
Output
Schema · Response
{
"type": "json",
"example": {
"ok": true,
"score": {
"tone": "salesy",
"verdict": "revise_then_send",
"spam_risk": 3,
"body_score": 71,
"cta_clarity": 6,
"subject_score": 62,
"top_improvements": [
{
"fix": "Reference their specific company milestone",
"area": "subject",
"issue": "Generic 'Quick question'"
},
{
"fix": "Open with the prospect-specific hook",
"area": "opening",
"issue": "Starts with 'I hope this finds you well'"
},
{
"fix": "Propose a specific 15-min slot",
"area": "cta",
"issue": "Vague 'let me know'"
}
],
"length_assessment": "too_long",
"rewritten_subject": "Saw your Q3 launch — one idea on the onboarding flow",
"personalization_score": 4,
"predicted_open_rate_pct": 28
}
}
}Tags
x402
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