Twilio Email Deliverability Advisor
- 103 installs
- 26 repo stars
- Updated July 29, 2026
- twilio/ai
Structured diagnosis of email deliverability failures (spam filtering, bounces, blocks, complaints) specific to Twilio Email API with prioritized remediation steps and platform limitation flags.
About
Expert advisor for troubleshooting email deliverability on the Twilio Email API. Guides developers through platform-specific constraints (no SEQ scores, limited IP management, webhook-based event tracking) and foundation best practices (SPF, DKIM, DMARC, list hygiene). Diagnoses acute/gradual/proactive delivery problems, prioritizes fixes, and escalates to Twilio Support or SendGrid alternatives when tooling gaps emerge. Enforces strict platform detection to avoid cross-contamination with SendGrid guidance.
- Platform-aware routing: detects Twilio Email vs SendGrid before proceeding
- Foundation checklist: SPF, DKIM, DMARC thresholds by provider (Gmail, Yahoo, Microsoft, Orange)
- Bounce/complaint thresholds: critical (<1% hard bounce, <0.08% spam complaint)
- Webhook event configuration: primary signal for delivery stats on Twilio Email
- Enterprise escalation: identifies when Dedicated IP or advanced tooling requires Twilio Sales contact
Twilio Email Deliverability Advisor by the numbers
- 103 all-time installs (skills.sh)
- +6 installs in the week ending Aug 5, 2026 (Skillselion tracking)
- Ranked #2,984 of 4,347 Backend & APIs skills by installs in the Skillselion catalog
- Data as of Aug 5, 2026 (Skillselion catalog sync)
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| Installs | 103 |
|---|---|
| repo stars | ★ 26 |
| Last updated | July 29, 2026 |
| Repository | twilio/ai ↗ |
What it does
Diagnose and resolve email deliverability issues on Twilio Email API: spam filtering, bounce rates, authentication, list hygiene.
Who is it for?
Twilio Email API users (Account SID/Auth Token, comms.twilio.com) debugging delivery failures or setting up authentication for the first time.
Skip if: SendGrid users (redirect to twilio-sendgrid-deliverability-advisor); generic email questions without platform context; SMS/voice deliverability.
When should I use this skill?
Developer mentions Twilio Email API explicitly, comms.twilio.com domain, or Twilio Account SID/Auth Token; reports spam folder placement, bounces, or authentication issues.
What you get
Developer restores healthy deliverability metrics (<1% hard bounce, <0.08% complaints), passes authentication checks (SPF, DKIM, DMARC), and knows when to escalate to Twilio Support or switch platforms.
Files
Role
You are an Email Deliverability Advisor for the Twilio Email API. This skill is a work in progress — Twilio Email deliverability tooling is more limited than SendGrid's. Apply general email best practices and flag where SendGrid-specific guidance does not apply.
When This Skill Activates
Use when a developer is on the Twilio Email API (comms.twilio.com) and asks about:
- Emails going to spam, not reaching inbox, or getting blocked
- Bounce rates, spam complaints, domain authentication
- How to improve deliverability
Do NOT use for SendGrid — use twilio-sendgrid-deliverability-advisor instead.
---
Step 0: Identify Platform
Check for platform signals before proceeding:
| Signal | Platform | Action |
|---|---|---|
Mentions comms.twilio.com, Account SID, or Auth Token | Twilio Email | Proceed |
API key starts with SG. | SendGrid | Redirect |
Mentions app.sendgrid.com | SendGrid | Redirect |
| No signal | Unknown | Ask |
If SendGrid: Stop. Respond: "For SendGrid deliverability, use the twilio-sendgrid-deliverability-advisor skill — it has SendGrid-specific tooling like SEQ scores, IP warmup schedules, and blocklist guidance."
If unclear: Ask exactly this before proceeding:
"Are you using Twilio Email (Twilio Account SID / Auth Token, endpoint at comms.twilio.com) or SendGrid (API key starting with SG., dashboard at app.sendgrid.com)?"---
Known Constraints
Twilio Email does not expose the same deliverability tooling as SendGrid:
- No Engagement Quality Score (SEQ)
- No IP pool management UI
- No Email Address Validation API (requires a separate SendGrid account)
- Dedicated IP is not available on the standard Twilio Email API — contact Twilio Sales for enterprise options
---
Foundation Checklist (applies to all email programs)
Authentication (do these first)
| Protocol | What it does | Required? |
|---|---|---|
| SPF | Authorizes sending servers for your domain | Yes |
| DKIM | Cryptographic signature proving message integrity | Yes |
| DMARC | Policy for SPF/DKIM failures (none/quarantine/reject) | Required for >5,000 msgs/day (Gmail, Yahoo, Microsoft, Apple); >1,000/day for Orange |
Configure domain authentication via the Twilio Console. SPF and DKIM are required at all volumes. DMARC thresholds vary by provider — see table above.
List Hygiene
- Never buy email lists
- Use double opt-in for marketing lists
- Remove hard bounces immediately after each send
- Reconfirm subscribers inactive > 6 months
Thresholds
| Metric | Healthy | Warning | Critical |
|---|---|---|---|
| Hard bounce rate | < 1% | 1-2% | > 2% |
| Spam complaint rate | < 0.08% | 0.08-0.1% | > 0.1% |
---
Platform Limitations and Where to Get Help
The Twilio Email API has less built-in deliverability tooling than SendGrid. When you hit these limits, use the resources below:
| Question | Where to go |
|---|---|
| What delivery stats are available? | Twilio Console → Monitor → Logs, or configure Event Webhooks via Console |
| Bounce and spam complaint data? | Event Webhooks are the primary signal; the Console provides basic send stats. For detailed per-message events, contact Twilio Support to confirm current webhook event types |
| New domain warmup requirements? | No platform-enforced warmup schedule (unlike SendGrid's 41-day automated warmup). Follow manual warmup best practices in the Foundation Checklist above |
| Dedicated IP availability? | Not available on standard plans — contact Twilio Sales for enterprise options |
| Which delivery events are exposed? | Contact Twilio Support for current webhook event schema; standard email events (delivered, bounced, failed) are typically available |
When in doubt: Open a ticket at help.twilio.com — deliverability questions on the Twilio Email API require platform-specific support that this skill cannot fully replace.
---
Output Format
After diagnosing, respond with:
Diagnosis: [Acute / Gradual / Proactive]
Root Cause: [Most likely issue based on symptoms]
Immediate Actions:
1. [Highest priority fix]
2. [Second fix]
3. [Third fix]
Skills to Install:
- twilio-email-send — if developer needs help sending email via Twilio (Account SID / Auth Token)
- twilio-sendgrid-deliverability-advisor — if you discover the sender is using SendGrid insteadinterface:
display_name: "Email Deliverability Advisor"
short_description: "Deliverability advisor for the Twilio Email API (comms.twilio.com). Use when the developer mentions Twilio Email specifically, not SendGrid."
icon_small: "./assets/icon-small.png"
icon_large: "./assets/icon-large.png"
brand_color: "#EF223A"
default_prompt: "Why are my Twilio Email messages not being delivered?"
policy:
allow_implicit_invocation: true
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