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Test and Improve Your Email Deliverability

Spam Cipher

See exactly where your emails land and why. Seed testing, content analysis, authentication monitoring, and AI classification in one platform.

Free Spam Check

or run a complete inbox placement test

SpamCipher

Trusted by Clients Worldwide

Customer Reviews

"Inbox rate went from 62% to 94% after SpamCipher pinpointed the exact content triggers. We were blind before this tool."

MR
Marcus Rivera
Head of Email, TechCorp

"Found a misconfigured DKIM key that had been silently failing for weeks. The DMARC validation alone saved us from a major crisis."

SK
Sarah Kim
Email Marketing Manager, MailFlow

"We run 200+ campaigns a month. SpamCipher replaced three separate tools in our stack. The seed testing is a game changer."

JP
James Park
Founder, SendPro Agency

Why Choose SpamCipher for Email Deliverability?

Inbox Insight

Powerful Spam Testing Tool

Test Your Email Deliverability:

Send a test email to our seed addresses and see real-time placement across Gmail, Outlook, Yahoo, iCloud, and 15+ providers. No guessing, no assumptions.

Real-time inbox vs. spam placement
15+ email providers monitored
Historical trend tracking
Try Inbox Test
app.spamcipher.com/reports/inbox
Inbox Placement Report
9.2
Score
Gmail
Inbox
Outlook
Promotions
Yahoo
Inbox
iCloud
Inbox
Content Analysis

60+ Rules Scan Every Element

Spam Testing:

Subject lines, body text, links, image-to-text ratio, and HTML structure are all checked against the same rules that spam filters use. Get a pass/warn/fail for each.

Subject line spam word detection
HTML structure validation
Image-to-text ratio checker
Analyze Content
app.spamcipher.com/reports/content
Content Analysis
18 rules evaluated
Subject line clean - 0 spam words detected PASS
HTML structure valid - W3C compliant PASS
Image ratio high - 62% (target <50%) WARN
Links verified - 3 links, 0 blacklisted PASS
Unsubscribe header present (List-Unsubscribe) PASS
Missing plain-text MIME part FAIL
Authentication

Authentication Checker

Automatic Tests & Alerts:

Validates your email authentication stack and flags missing records, weak keys, alignment issues, and misconfigurations before they hurt your sender reputation.

SPF, DKIM, DMARC alignment
Weak key detection (1024-bit warnings)
DNS record configuration check
Check Auth
app.spamcipher.com/reports/auth
Authentication Status
All Aligned
SPF
v=spf1 aligned
DKIM
2048-bit RSA key
DMARC
p=reject; rua=set
Return-Path domain matches From domain PASS
DNS lookup count: 6/10 (under limit) PASS
BIMI record not found (optional) INFO
AI Classifier

AI Spam Classifier

Content Analysis:

Our model is trained on millions of spam/ham decisions across major providers. It predicts where your email will land with 98% accuracy, before you send to a single real subscriber.

98% prediction accuracy
Provider-specific models
Confidence scoring per prediction
Try AI Analysis
app.spamcipher.com/reports/ai
AI Classification Result
98%
Conf
Predicted Placement
PRIMARY INBOX
Provider Breakdown
Gmail
98%
Outlook
91%
Yahoo
95%
iCloud
97%
Developers

API 2.0 Integration

Integrate deliverability testing directly into your CI/CD pipeline, ESP workflow, or SaaS product. RESTful API with comprehensive documentation and SDKs for Node.js, Python, and Go.

<200ms
Average response time
99.95%
Uptime SLA
10k+
Requests/min
Get API Access
Node.js
import { SpamCipher } from '@spamcipher/sdk'; const client = new SpamCipher({ apiKey: process.env.SPAMCIPHER_KEY }); // Analyze email content const result = await client.analyze({ html: emailHtml, subject: 'Your order ships today', from: 'news@acme.com' }); console.log(result.score); // 9.2 console.log(result.placement); // "inbox" console.log(result.rules); // [{...}]
Integrations

Compatible with All Email Marketing Tools

Works with every major ESP and email platform. Send from your tool, test with SpamCipher.

Mailchimp
SendGrid
Amazon SES
Postmark
Mailgun
SparkPost
Brevo
Klaviyo
ActiveCampaign
HubSpot
ConvertKit
Drip
Campaign Monitor
Constant Contact
MailerLite
SMTP.com
Resources

From Our Blog

Expert guides on email deliverability, authentication, and inbox placement strategy.

SPF, DKIM &
DMARC Guide
May 20, 2026
The Complete Guide to Email Authentication in 2026
Everything you need to know about SPF, DKIM, DMARC, and the new BIMI standard for verified brand logos.
Read more →
Gmail 2026
Deliverability
May 12, 2026
Gmail's 2026 Filtering Changes: What Senders Must Know
Google has tightened its spam filtering again. Here is what changed and how to adapt your sending strategy.
Read more →
Inbox Placement
Testing 101
April 28, 2026
Why You Need Seed-Based Inbox Placement Testing
Open rate metrics lie. Seed testing gives you ground truth about where your emails actually land.
Read more →

Stop guessing. Start landing in the inbox.

Join thousands of email teams who use SpamCipher to test, monitor, and improve their deliverability.

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Free to start. No credit card required.

Frequently Asked Questions

Inbox placement testing uses seed email accounts at major providers (Gmail, Outlook, Yahoo, etc.) to determine exactly where your email lands — primary inbox, promotions tab, spam folder, or not delivered at all. Unlike open-rate tracking, seed testing gives you ground truth about deliverability.
We evaluate your email against 60+ rules that mirror what real spam filters check: subject line keywords, image-to-text ratio, HTML structure, link reputation, unsubscribe headers, and more. Each rule returns pass, warning, or fail with specific guidance on how to fix issues.
No. SpamCipher works with any ESP or email sending infrastructure. You simply send a test email to our seed address from your existing setup, and we analyze the result. No DNS changes, no code integration, no SDK installation required to get started.
Our machine learning model is trained on millions of real spam/ham classification decisions from major email providers. It predicts where your email will land across Gmail, Outlook, Yahoo, and others with 98% accuracy — giving you a pre-send confidence score before you send to your actual subscriber list.
Yes. SpamCipher offers a free forever tier that includes 5 content scans per day, basic authentication checks, and access to our free tools (Spam Score Checker, Blacklist Checker, DMARC Generator, SPF Flattener). No credit card required to sign up.
SpamCipher combines four layers of analysis in one platform: seed-based inbox placement testing, 60+ rule content analysis, authentication validation (SPF/DKIM/DMARC), and AI-powered spam classification. Most competitors offer one or two of these. We also provide a developer-first API for CI/CD integration.