InboxPreview
Executive Summary
Vision Statement
Democratize professional email testing by providing enterprise-grade preview capabilities at freelancer-friendly pricing.
Problem Summary
Litmus is retiring PutsMail, its free HTML email testing tool, on September 30, 2025. This leaves freelancers and small businesses without an affordable solution for testing email client compatibility, forcing them toward expensive alternatives like Litmus's paid suite ($99+/month).
Proposed Solution
A web-based SaaS platform offering quick HTML email previews across major clients (Gmail, Outlook, Apple Mail) with essential testing features at accessible pricing tiers. Targets users needing lightweight testing without enterprise suite costs.
Market Analysis
Target Audience
- Freelance email designers: Solo operators creating campaigns for clients
- Small e-commerce teams: Businesses with 1-5 marketing staff
- Bootstrapped startups: Early-stage companies needing cost-effective solutions
- Agency contractors: Independent specialists requiring client-facing testing
Niche Validation
The retirement of PutsMail (acquired by Litmus in 2014) creates immediate market gap. Reddit comments confirm frustration among small operators priced out of Litmus ($99+/month). Validity's 2025 State of Email Report shows 22% of marketers struggle with ROI measurement, indicating budget sensitivity[4].
Google Trends Keywords
Market Size Estimation
SMB-focused email testing tools ($120M segment)
Freelancer/small team niche ($18M serviceable market)
Global email marketing software market ($1.5B in 2025)
Competitive Landscape
| Competitor | Pricing | Key Limitation |
|---|---|---|
| Litmus | $99+/month | Prohibitive for SMBs |
| Email on Acid | $49+/month | Complex feature bloat |
| Mailhog | Free | Local setup required |
| Parcel.io | Free | Limited client coverage |
Opportunity: Position between free tools (insufficient) and enterprise suites (overkill)[1][2]
Product Requirements
User Stories
As a freelancer, I want to paste HTML and instantly see Gmail/Outlook renders so I can fix layout issues before sending
As a small business owner, I need to share test reports with my team via URL to collaborate on fixes
As a budget-conscious user, I require clear pricing tiers so I only pay for necessary features
MVP Feature Set
HTML/CSS input with syntax validation
Client previews (Gmail, Outlook, Apple Mail)
Shareable test reports
Account-based test history
Stripe subscription integration
Non-Functional Requirements
Performance: Render results < 45s for 90% of tests
Security: Sandboxed rendering environments
Reliability: 99.5% uptime SLA
Key Performance Indicators
Activation rate: % free users running first test within 24h
Paid conversion: % free users upgrading within 30 days
Rendering accuracy: Client preview match rate vs actual emails
Go-to-Market Strategy
Core Marketing Message
Your PutsMail replacement is here: Professional email testing without enterprise pricing. Preview campaigns in 90 seconds, not 90 dollars.
Initial Launch Channels
- Reddit communities: Targeted posts in r/Emailmarketing and r/web_design
- Freelancer platforms: Partnerships with Upwork/Fiverr email designers
- Beta waitlist: Leverage PutsMail retirement announcements (Sept 2025)
Strategic Metrics
Problem Urgency
High
Solution Complexity
Medium
Defensibility Moat
Community-driven development:
- Open-source rendering engines
- User-requested client support
- Transparent roadmap voting
Technical moat:
- Automated client rendering farm
- Proprietary rendering accuracy scoring
Source Post Metrics
Business Strategy
Monetization Strategy
Freemium model:
- Free: 5 tests/month, basic clients
- Starter ($5/month): 50 tests, priority rendering
- Pro ($15/month): Unlimited tests, all clients + analytics
Financial Projections
| Tier | Users (Y1) | MRR Contribution |
|---|---|---|
| Free | 5,000 | $0 |
| Starter | 1,000 | $5,000 |
| Pro | 500 | $7,500 |
| Total: $12,500 MRR by Year 1 end |
Tech Stack
Node.js (Express) for scalable test queue management
PostgreSQL for relational test metadata + Redis for job caching
Next.js with TypeScript for SSR-optimized dashboard and preview rendering
- Puppeteer Cluster: Headless browser orchestration
- AWS Lambda: On-demand rendering containers
- Stripe: Subscription billing
- SendGrid: Notification emails
Risk Assessment
Identified Risks
- Litmus feature retaliation: Enterprise competitor adds lightweight tier
- Rendering inaccuracies: Client updates break preview reliability
Mitigation Strategy
- Community-driven roadmap: Prioritize features requested by users
- Versioned rendering: Maintain client-specific rendering engines for stability