Everything you need for
email deliverability
One platform. Zero spam. Full control over your sender reputation. Stekpad combines AI-generated warm-up emails, adaptive volume control, inbox placement testing, DNS monitoring, blacklist protection, and real-time analytics into a single email deliverability platform that protects and improves your sender reputation on autopilot.
AI-Generated Email Content
Every warm-up email sent through Stekpad is uniquely generated by advanced AI models, starting with Llama 3.3 70B via the Groq API. Unlike traditional warm-up tools that recycle the same handful of templates, our AI creates genuinely unique conversations that are indistinguishable from real human email exchanges. This is critical because modern spam filters use pattern recognition to identify synthetic warm-up traffic — and repeating content is the single biggest red flag.
Our proprietary 4-layer prompt system ensures every email feels authentic. The first layer assigns a detailed persona — a marketing director in Chicago, a software engineer in Berlin, a healthcare consultant in London — each with distinct writing styles, industry vocabulary, and conversational patterns. The second layer injects conversation context, so reply emails reference specific points from earlier messages in the thread. The third layer introduces controlled variation in length, formality, signature style, and whether the email asks a question or provides an answer. The fourth layer applies anti-detection rules: varying greetings, avoiding repetitive sentence structures, and randomizing punctuation patterns.
Stekpad ships with over 30 pre-built personas spanning technology, finance, healthcare, marketing, legal, education, and more. Each persona carries a full profile: name, company, role, preferred topics, writing tone, and language. The system supports multi-language content generation in English, French, Spanish, and German — with additional languages coming soon. Thread continuation means the AI reads the entire conversation history before generating a reply, producing multi-turn exchanges that span 3 to 8 messages and feel like genuine business correspondence.
- Powered by Llama 3.3 70B (Groq API) with automatic fallback to Llama 3.1 8B, Gemini Flash, and local Ollama
- 4-layer prompt architecture: Persona, Context, Variation, and Anti-Detection
- 30+ industry-specific personas with unique writing styles and vocabulary
- Multi-turn thread continuation — AI reads full conversation history before replying
- Subject line variation engine that generates contextually appropriate subjects
- Multi-language support: English, French, Spanish, German (more coming soon)
- Zero repeated content — every single email is unique across all users
Sarah Mitchell
sarah@acme-consulting.com
Re: Quick question about Q2 marketing strategy
Hi David, thanks for sharing those campaign results. The 23% increase in open rates is impressive — especially considering the audience segment you targeted.
I was curious about your approach to subject line testing. We have been experimenting with personalization tokens and seeing mixed results depending on the industry vertical...
Smart Ramp-Up Engine
Building sender reputation requires patience and precision. Send too many emails too quickly and you will trigger spam filters. Send too few and your warm-up takes months instead of weeks. Stekpad's Smart Ramp-Up Engine eliminates the guesswork by continuously monitoring real-time deliverability signals and automatically adjusting your sending volume to maximize warm-up speed without risking your reputation.
The engine operates on a simple but powerful set of rules. When your mailbox health score is above 90, the system increases volume by up to 3 emails per day. Between 80 and 90, it adds 1 per day. Below 80, warm-up pauses entirely until metrics recover. If bounce rate exceeds 1%, the engine triggers an automatic 24-hour pause. If spam rate climbs above 10%, volume drops by 50%. Above 25% spam rate, warm-up halts immediately and you receive an alert. These thresholds are based on industry best practices and real-world data from thousands of mailbox warm-ups.
Timing matters as much as volume. Stekpad uses a Gaussian distribution model centered on 10:00 AM and 2:00 PM in the recipient's timezone to ensure emails arrive during natural business hours. Each send time includes a randomized jitter of plus or minus 15 minutes, so no two days look identical. Reply timing follows a log-normal distribution between 3 and 45 minutes, mimicking how real people respond to emails. Even read time is simulated — between 10 and 60 seconds — to generate realistic engagement signals.
- Adaptive volume control: +3/day when health > 90, +1/day when 80-90, pause when < 80
- Automatic 24-hour pause when bounce rate exceeds 1%
- Volume reduction of 50% when spam rate exceeds 10%, full pause above 25%
- Gaussian-distributed send times centered on 10 AM and 2 PM (recipient timezone)
- Randomized jitter of plus or minus 15 minutes on every scheduled send
- Log-normal reply timing between 3 and 45 minutes for realistic engagement
- Set it and forget it — the engine adapts automatically to protect your reputation
Inbox Placement Testing
Sender reputation is invisible until something goes wrong. Your emails might be landing in spam for weeks before a customer mentions it. Stekpad's inbox placement testing gives you definitive visibility into where your emails actually land across every major email provider — Gmail, Outlook, Yahoo, and AOL — so you can identify and fix deliverability problems before they impact your business.
Each placement test sends a controlled email to seed mailboxes hosted at every major provider. Within minutes, you see exactly where each test email landed: primary inbox, spam folder, promotions tab, updates tab, or if it was silently dropped. Results are broken down by provider so you can pinpoint whether a deliverability issue is universal or specific to a single provider — a crucial distinction because Gmail, Outlook, and Yahoo each use different spam filtering algorithms with different reputation signals.
Historical tracking lets you monitor placement trends over time. See how your inbox rate improves as warm-up progresses, spot regressions early, and correlate placement changes with DNS configuration updates or sending volume adjustments. Starter plans include one placement test per month, Pro plans include four tests per month with the option to run them on demand, and Enterprise plans include unlimited testing with automatic weekly scheduling.
- Test delivery across Gmail, Outlook, Yahoo, AOL, and additional providers
- See exactly where each email lands: inbox, spam, promotions, updates, or missing
- Provider-specific insights — pinpoint issues unique to Gmail vs Outlook vs Yahoo
- Historical placement trend tracking with visual charts
- Scheduled automated tests: monthly on Starter, weekly on Pro, unlimited on Enterprise
- Know before your customers know — catch deliverability drops proactively
| Provider | Inbox | Spam | Promo |
|---|---|---|---|
| Gmail | 96% | 3% | 1% |
| Outlook | 93% | 4% | 2% |
| Yahoo | 89% | 7% | 3% |
| AOL | 91% | 5% | 3% |
Overall inbox rate: 92.3%
DNS Health Monitoring
Email authentication records — SPF, DKIM, and DMARC — are the foundation of your sender reputation. A single misconfigured record can cause every email you send to land in spam, and the worst part is that DNS changes can happen without warning. A hosting migration, a new marketing tool adding its own SPF include, or an expired DKIM key rotation can silently break your authentication and tank your deliverability overnight.
Stekpad continuously monitors all of your email authentication records and alerts you the moment something changes or breaks. Our DNS health checker validates SPF records for correct syntax and checks that you are not exceeding the 10 DNS lookup limit — a common pitfall that causes SPF to fail silently. DKIM monitoring verifies that your signing keys are properly published and accessible. DMARC monitoring confirms that your policy is set correctly and that aggregate reports are being received.
Beyond the core authentication trio, Stekpad also monitors your MX records to ensure mail routing is correct, checks for BIMI (Brand Indicators for Message Identification) support, and validates that your reverse DNS (PTR) records match your sending IP. When an issue is detected, you receive an instant alert along with step-by-step fix guidance tailored to your specific DNS provider — whether that is Cloudflare, Route 53, GoDaddy, or any other registrar.
- Continuous SPF, DKIM, and DMARC monitoring with instant misconfiguration alerts
- SPF lookup limit checking — detect when you exceed the 10-lookup maximum
- DKIM key validation — verify signing keys are published and accessible
- DMARC policy monitoring with aggregate report verification
- MX record monitoring to ensure correct mail routing
- BIMI support checking for brand logo display in supported clients
- Step-by-step fix guidance tailored to your DNS provider (Cloudflare, Route 53, etc.)
Blacklist Protection
Getting listed on an email blacklist is one of the most damaging things that can happen to your sender reputation — and it can happen to anyone. A compromised account, a spike in bounces from a bad list, or even sharing an IP range with a spammer can land your domain or IP on a DNS-based blackhole list (DNSBL). Once listed, your emails may be rejected outright by receiving servers, and delisting can take days or even weeks depending on the blacklist operator.
Stekpad monitors over 100 DNSBL databases continuously — including Spamhaus SBL, XBL, PBL, and DBL, Barracuda, SURBL, URIBL, SpamCop, and dozens more. Both your sending IP addresses and your domain names are checked. When a listing is detected, Stekpad immediately pauses warm-up activity to prevent further reputation damage and sends you a real-time alert with details about which blacklist flagged you, what the listing reason was, and step-by-step delisting instructions specific to that blacklist operator.
Historical blacklist tracking lets you see past listings, how long they lasted, and when they were resolved. This data is invaluable for identifying patterns — for example, if listings correlate with specific sending volumes or sending times. The proactive monitoring approach means you find out about a listing within minutes of it happening, not days later when customers start complaining about missing emails.
- Continuous monitoring across 100+ DNSBL databases including Spamhaus, Barracuda, SURBL
- Both IP address and domain name monitoring for comprehensive coverage
- Immediate warm-up pause when a listing is detected to limit reputation damage
- Real-time alerts with listing reason and blacklist-specific delisting guidance
- Historical blacklist tracking — see past listings, duration, and resolution timeline
- Get alerted within minutes of a listing — before your customers notice delivery issues
Scanned 100+ DNSBL databases. Next scan in 55 minutes.
Real-Time Analytics & Health Score
Email deliverability is not a single metric — it is the result of dozens of interacting signals that change daily. Stekpad distills all of these signals into a single composite health score from 0 to 100, giving you an instant, actionable understanding of your sender reputation. The health score is not a vanity metric: it directly drives the Smart Ramp-Up Engine, meaning every point you gain translates into faster warm-up progress.
The health score is calculated from seven weighted metrics. Inbox placement rate carries the highest weight at 30%, because where your emails land is the ultimate measure of deliverability. Bounce rate accounts for 20% (inverted — lower is better). Reply rate at 15% measures engagement quality. Open rate at 10% tracks initial engagement. DNS health at 10% reflects your authentication configuration. Blacklist status at 10% monitors your listing status. Finally, age and consistency at 5% rewards sustained warm-up activity over time.
The analytics dashboard provides daily, weekly, and monthly trend views for every metric. You can view data at the per-mailbox level or as an aggregate across all your mailboxes. Every data point is exportable as CSV for reporting to stakeholders or importing into your own analytics tools. Alert thresholds are fully customizable — set your own warning levels for bounce rate, spam rate, or health score drops, and receive notifications via email or webhook when thresholds are breached.
- Composite health score (0-100) calculated from 7 weighted deliverability metrics
- Inbox placement rate (30%), bounce rate (20%), reply rate (15%), open rate (10%)
- DNS health (10%), blacklist status (10%), age and consistency (5%)
- Daily, weekly, and monthly trend views with interactive charts
- Per-mailbox and aggregate views across all your sending domains
- CSV export for stakeholder reports and external analytics tools
- Customizable alert thresholds — get notified when metrics cross your defined limits
Composite Health Score
Additional capabilities
Beyond the core warm-up engine, Stekpad includes everything you need to manage email deliverability at scale.
Team Collaboration
Invite team members with granular role-based permissions. Share dashboards, manage mailboxes collaboratively, and maintain full audit trails across your organization.
API Access
Full RESTful API with webhook support. Integrate Stekpad into your existing workflows, build custom automations, and pull data into your own dashboards.
OAuth Connections
Connect Gmail and Outlook with one click via OAuth. No app passwords needed — secure, token-based authentication with automatic renewal.
Custom SMTP Support
Bring any SMTP provider. Whether you use SendGrid, Amazon SES, Postmark, or your own mail server, Stekpad works with any SMTP configuration.
Multi-Domain Management
Manage multiple domains and mailboxes from a single dashboard. Aggregate analytics, compare performance, and apply warm-up strategies across all your sending domains.
Automated Scheduling
Set your warm-up schedule once and forget it. Timezone-aware scheduling ensures emails are sent during realistic business hours for your recipients.
Email Content Preview
Review every AI-generated email before it sends. Approve content, adjust tone, or regenerate — you always have full control over what leaves your mailbox.
White-Label Dashboard
Coming soon for agencies: embed Stekpad into your own platform with custom branding, client management, and per-client billing.
Stekpad vs Traditional Warm-Up
See how our AI-powered, signal-adaptive approach compares to legacy warm-up tools that rely on fixed schedules and recycled templates.
| Feature | Stekpad | Traditional |
|---|---|---|
| AI-generated content | Unique every time | Same templates recycled |
| Smart ramp-up | Adaptive to real-time signals | Fixed schedule |
| Inbox placement testing | Multi-provider automated | Manual only |
| DNS monitoring | Continuous with alerts | Periodic manual checks |
| Blacklist alerts | Real-time, 100+ databases | Manual checks |
| Health score | Weighted 7-metric composite | Basic open/bounce metrics |
| API access | Full REST API + webhooks | Limited or none |
| Free plan | Yes, no credit card | Rarely available |
Why Email Warm-Up Matters for Deliverability
Email deliverability is the percentage of your emails that successfully reach the recipient's inbox rather than being filtered into spam, bounced, or silently dropped. For businesses that rely on email for sales outreach, marketing campaigns, or transactional communications, poor deliverability means lost revenue. Studies show that the average inbox placement rate across industries is only 83% — meaning nearly 1 in 5 emails never reaches the intended recipient.
Email warm-up is the process of gradually building sender reputation for a new or cold email address by sending increasing volumes of legitimate-looking emails and generating positive engagement signals (opens, replies, marking as important). Internet Service Providers (ISPs) like Gmail, Outlook, and Yahoo evaluate every sending domain and IP address based on historical sending patterns, engagement metrics, authentication records, and blacklist status. A new email address with no sending history is treated with suspicion — just like a new credit card holder has no credit score.
Traditional warm-up tools use pre-written email templates and fixed sending schedules, which makes the warm-up traffic easy for sophisticated spam filters to identify and discount. Stekpad takes a fundamentally different approach: every email is generated by AI to be unique, sending volumes adapt in real-time to deliverability signals, and the entire process is monitored by continuous DNS checking, blacklist scanning, and inbox placement testing. The result is faster, safer warm-up that builds genuine sender reputation.
Whether you are warming up a new domain for cold outreach, recovering a domain with damaged reputation, or maintaining the deliverability of an active sending domain, Stekpad provides the tools and intelligence you need. Our free plan lets you get started with one mailbox and 5 emails per day — no credit card required. Our Starter plan at 9.99 euros per month adds a second mailbox and 20 emails per day. Pro and Enterprise plans unlock even more mailboxes, higher daily volumes, dedicated seed boxes, and advanced features like API access and team collaboration.