Frequently Asked Questions
Everything you need to know about SendMailOS credits, API, deliverability, and account management.
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Pricing & Credits
- How does the Free Plan work?
- You get 25,000 free emails every month. Your credits automatically reset on the 1st of each month. No credit card is required to start, and you get full access to all features except dedicated IPs.
- Do purchased 'Top Up' credits expire?
- Yes. Purchased top-up credits are valid for 30 days from the date of purchase. We always prioritize using your free monthly allowance first before using your paid credits.
- What happens if I run out of credits?
- If you exhaust your monthly free allowance and have no top-up credits, sending will be paused until the next month or until you purchase a top-up pack. We'll alert you before this happens.
- Do you offer refunds for unused credits?
- We do not offer refunds for unused credits or monthly plan fees. However, if you believe there was a billing error, please contact support immediately.
- Are there any setup fees?
- No. There are no setup fees, hidden charges, or contracts. You only pay for the credits you purchase (or your monthly subscription if you upgrade).
- Is storage really free?
- Yes! You can store unlimited contacts and unlimited images (within fair use) for free. We only charge based on the number of emails you send.
Sending & Deliverability
- Are there daily sending limits?
- No. Unlike competitors who throttle you (e.g., 300/day), SendMailOS allows you to send your entire allowance instantly. If you have 25,000 credits, you can send 25,000 emails in one hour.
- Do you have dedicated IPs?
- Yes. Dedicated IPs are available on our Pro and Scale plans. For the Free, Starter, and Growth plans, we use a carefully monitored high-reputation shared IP pool.
- How do you handle spam complaints?
- We have a strict zero-tolerance policy for spam. If your spam complaint rate exceeds 0.1%, your account may be suspended pending review. We strictly prohibit purchased lists.
- Can I send cold emails?
- No. SendMailOS is for opt-in transactional and marketing emails only. You must have permission from recipients. Sending unsolicited cold emails will result in an immediate ban.
- What is your average delivery speed?
- For transactional emails, our P99 delivery time is under 2 seconds. For bulk campaigns, we dynamically scale our workers to ensure timely delivery.
API & Technical
- Do you support SMPT?
- Currently, we focus on our REST API for maximum performance and security. SMTP support is on our roadmap for Q2 2026.
- How do I verify my domain?
- You simply add the CNAME records we provide to your DNS provider (Cloudflare, GoDaddy, etc.). This sets up SPF and DKIM automatically. Verification usually takes less than 5 minutes.
- Can I use webhooks?
- Yes. You can subscribe to 'email.sent', 'email.delivered', 'email.opened', 'email.clicked', 'email.bounced', and 'email.complained' events. We send a JSON payload to your endpoint in real-time.
Account & Security
- Is my data secure?
- Absolutely. We use encryption at rest and in transit (TLS 1.3). We are fully GDPR compliant and host our servers in secure EU data centers.
- How do I export my data?
- You own your data. You can export your contact lists and campaign reports as CSV files at any time from the dashboard.
- Can I manage multiple domains?
- Yes. You can add and verify as many sending domains as you need under a single account. Credits are shared across all domains.