# SendGrid Architecture Reference
**Cold Bore Ballistics LLC — Confidential**
Last updated: 2026-06-06
Status: Active — domain authentication complete; IVR voicemail delivery pending Function deployment

> This document is the authoritative record of what exists in the CBB SendGrid account. It is the single source of truth for account details, domain authentication state, API keys, and configuration. Never duplicate this information in other documents — cross-reference here instead.

---

## Account

| Field | Value |
|---|---|
| **Account type** | Free (100 emails/day) |
| **User ID** | `108827327` |
| **Reputation** | 100 |
| **Created** | 2026-06-06 |
| **Purpose** | Transactional system email — IVR voicemail delivery; future app-triggered notifications |

> SendGrid is NOT used for marketing email. It is used exclusively for transactional system-to-mailbox delivery where an SMTP relay or direct API call is required from a non-M365 system (e.g., Twilio Functions).

---

## API Keys

| Name | Key ID | Secret location | Permissions | Purpose | Created |
|---|---|---|---|---|---|
| `claude-code-cli` | *(regenerated — see Key Vault)* | `kv-cbb-shared-prod` → `sendgrid-claude-code-cli-secret` | Full Access | Operator/CLI account management | 2026-06-06 |
| `twilio-ivr` | *(regenerated — see Key Vault)* | `kv-cbb-shared-prod` → `sendgrid-twilio-ivr-secret` | Mail Send only | Twilio IVR voicemail Function | 2026-06-06 |

> Never use the `claude-code` key in application code — use the restricted `twilio-ivr` key for the Twilio Function.

---

## Authenticated Domains

| Domain | ID | Subdomain | Default | Status | Verified |
|---|---|---|---|---|---|
| `coldboreballisticsllc.com` | `31320832` | `em` | Yes | Active | 2026-06-06 |
| `scope-dope.com` | `31320833` | `em` | No | Active | 2026-06-06 |

### DNS Records (all CNAME, added to Namecheap CBB account)

**`coldboreballisticsllc.com`:**

| Host | Type | Value |
|---|---|---|
| `em.coldboreballisticsllc.com` | CNAME | `u108827327.wl078.sendgrid.net` |
| `s1._domainkey.coldboreballisticsllc.com` | CNAME | `s1.domainkey.u108827327.wl078.sendgrid.net` |
| `s2._domainkey.coldboreballisticsllc.com` | CNAME | `s2.domainkey.u108827327.wl078.sendgrid.net` |

**`scope-dope.com`:**

| Host | Type | Value |
|---|---|---|
| `em.scope-dope.com` | CNAME | `u108827327.wl078.sendgrid.net` |
| `s1._domainkey.scope-dope.com` | CNAME | `s1.domainkey.u108827327.wl078.sendgrid.net` |
| `s2._domainkey.scope-dope.com` | CNAME | `s2.domainkey.u108827327.wl078.sendgrid.net` |

---

## Mail Settings

| Setting | State | Notes |
|---|---|---|
| Click tracking | Disabled | Not appropriate for internal system emails |
| Open tracking | Disabled | Pixel-based, unreliable, not needed for internal |
| Bounce forwarding | Enabled | Bounces forwarded to `admin@coldboreballisticsllc.com` |
| Subscription tracking | Disabled | Not applicable — transactional only |
| Google Analytics | Disabled | Not applicable |

---

## Integrations

| System | Status | Notes |
|---|---|---|
| Twilio IVR voicemail Function | Pending | Awaiting Function deployment — will use a dedicated Mail Send API key |

---

## Cost Tracking

| Resource | Monthly cost | Notes |
|---|---|---|
| Free tier | $0 | 100 emails/day included |
| **Current total** | **$0/month** | Well within free tier at current volume |

> At ~6 voicemail options × estimated call volume, free tier is sufficient indefinitely at launch scale. Upgrade to Essentials ($19.95/month, 50,000 emails/month) only if daily volume approaches 100 emails.

---

## Architecture Decisions

| Decision | Choice | Rationale |
|---|---|---|
| SendGrid vs M365 SMTP | SendGrid | M365 app passwords disabled by security policy; client secrets blocked by tenant policy; certificates add unnecessary complexity for a system email relay |
| SendGrid vs Entra ID OAuth | SendGrid | SendGrid is purpose-built for transactional system email; Entra ID OAuth from Twilio Functions adds auth complexity with no benefit |
| Tracking | All disabled | Emails are internal system notifications — tracking pixels and click rewrites are inappropriate and add noise |
| Default domain | `coldboreballisticsllc.com` | Corporate domain is the default sender; `scope-dope.com` used explicitly for ScopeDOPE-originated emails |

---

## Document Control

| Field | Value |
|---|---|
| **Document owner** | `jschwefel@coldboreballisticsllc.com` |
| **Classification** | Confidential (03_-_Confidential/) |
| **Location** | `OneDrive/CBB_Corporate/03_-_Confidential/Infrastructure/SendGrid/SendGrid_Architecture_Reference.md` |
| **Cross-references** | `SendGrid_Operating_Runbook.md`; `SendGrid_Rebuild_Guide.md`; `Twilio_Architecture_Reference.md` |
| **Created** | 2026-06-06 |
| **Last updated** | 2026-06-06 |
| **Next full review due** | 2027-06-06 |

---

## Revision Control Block

| Rev | Date | Changed By | Reviewed By | Approved By | Summary |
|-----|------|------------|-------------|-------------|---------|
| 0.9 | 2026-06-06 | jschwefel | — | — | Initial release |
