Are you searching for a reliable Postmark alternative that accepts cryptocurrency payments? Many businesses love Postmark’s deliverability but need more flexible payment options. With our crypto-friendly email delivery service, you can pay using Bitcoin and other digital currencies while enjoying the same professional SMTP and API features.
Why Use a Postmark Crypto Alternative?
Crypto SMTP Payments – Skip credit cards and banking restrictions. Pay for email services with Bitcoin, USDT, or other cryptocurrencies.
High Deliverability – Just like Postmark, our platform is built for transactional email, ensuring your messages land in the inbox.
Developer Friendly – Easy SMTP and API integration with clear documentation for a quick switch from Postmark.
Privacy First – We respect your data. No unnecessary tracking, just secure and reliable email delivery.
Who Is This For?
Startups that want affordable email delivery with crypto payments.
Privacy-focused companies who don’t want card processors involved.
Postmark Alternative with Bitcoin Payments
If you’ve been looking for a Postmark alternative with Bitcoin, our service is designed for you. We combine reliable email infrastructure with cryptocurrency payments, giving you the freedom to manage your emails without borders.
Final Thoughts
Postmark is a great service, but if you need an SMTP provider that accepts crypto, we’re the solution. With fast email delivery, fair pricing, and Bitcoin payments, you’ll have everything you need to send transactional and marketing emails at scale.
Try our Postmark alternative with crypto payments today and take control of your email delivery.
For Routing & Transactional emails only. Change the quantity to purchase additional months. Not for sending mass mail or newsletters. Have questions? Send us an email support@kingmailer.co. We accept Bitcoin, USDT, Binance Pay, Credit cards and PayPal payments.
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
This side-by-side comparison is based on features listed on Mailjet’s pricing page. The features listed below are relevant for sending transactional emails, we are not in the email marketing business, so we didn’t compare any email marketing features, as we are not in that business.
Features
Mailjet
Kingmailer
No daily sending limit
✔
✔
No logo
✔
✔
Email support
✔
✔
Unlimited contacts
✔
✔
Full API Access
✔
✔
Advanced email editor
✔
x
Advanced reporting
✔
✔
Dedicated IP upon request
If approved
If approved
Premium features
Additional users
5
10
Deliverability Experts
✘
✔
Contact us info@kingmailer.co
FAQ
How does Kingmailer work?
Kingmailer is an email delivery and deliverability service that empowers businesses to easily send email from their (web) apps. It’s free to sign up and easy to get started.
How does your billing work?
You will be billed every 30 days. We accept PayPal and all major credit and debit cards. Your payment info is stored and processed securely by 2Checkout and never touches our servers.
How do I send emails with Kingmailer?
Since Kingmailer has both an HTTP API and an SMTP endpoint, you can choose to send the way you’d like. Both ways have their advantages… SMTP is easy to setup and often plug and play, but API is much more reliable at scale. If you’re building an application, we recommend using our HTTP API.
How many dedicated IP’s do I need? Can I get more?
You don’t actually need a dedicated IP when using Kingmailer, because great email delivery is already included in your plan, no additional investment is needed for this from your end.
How many users come with each plan?
Every Kingmailer plan (free and paid) allows you to add as many users as you need to your account at no additional cost. We think it’s much easier this way to manage the account with your team, without sharing login credentials.
I want to test Kingmailer first. How can I do that?
The free trial is ideal for those looking to test out the service. Keep in mind that the free trial has a max 20 emails per hour limit and a max 20 recipients limit. If you reach these limits, your email traffic will be paused. The free plan has 30 days of log retention so you can easily troubleshoot issues.
Commencez à envoyer, recevoir, acheminer / transférer vos e-mails, en utilisant notre serveur SMTP gratuit. Après votre inscription, vous aurez votre nom d’utilisateur SMTP et votre mot de passe SMTP gratuits. Et aussi l’API Web SMTP gratuite.
Envoyez jusqu’à 20 000 e-mails par mois à jusqu’à 5 000 destinataires mensuels uniques.Pour les e-mails de routage et transactionnels uniquement. Pas pour l’envoi de courriers électroniques ou de newsletters en masse. Besoin d’un plan personnalisé ou avez des questions? Envoyez-nous un e-mail info@kingmailer.co. Nous acceptons Bitcoin, Ethereum, Bitcoin Cash, Litecoin, Dogecoin, PayPal et toutes les principales cartes.
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
Comment ça marche?
After signing up with Kingmailer you will have your own free SMTP mail server, with username and password. You can use the SMTP server and integrate with your web apps for example WordPress.
With Kingmailer you don’t need to purchase a dedicated IP or “managed email service” or pay extra for “great delivery” to enjoy great deliverability. Great email delivery is already included in your plan, doesn’t matter which plan you use. You can also pay with Bitcoin.
20,000 emails per month. 5,000 monthly unique recipients. For Routing & Transactional emails only. Not for sending mass mail or newsletters. Have questions? Email us support@kingmailer.co. We accept Bitcoin, Ethereum, Dogecoin, PayPal and all major cards. Check our Pricing page for more details.
FAQ
How can I upgrade my account?
Send us an email to upgrade your account.
How does Kingmailer work?
Kingmailer is an email delivery and deliverability service that empowers businesses to easily send email from their (web) apps. It’s free to sign up and easy to get started.
How does your billing work?
You will be billed every 30 days. We accept PayPal and all major credit and debit cards. Your payment info is stored and processed securely by 2Checkout and never touches our servers.
How do I send emails with Kingmailer?
Since Kingmailer has both an HTTP API and an SMTP endpoint, you can choose to send the way you’d like. Both ways have their advantages… SMTP is easy to setup and often plug and play, but API is much more reliable at scale. If you’re building an application, we recommend using our HTTP API.
How many dedicated IP’s do I need? Can I get more?
You don’t actually need a dedicated IP when using Kingmailer, because great email delivery is already included in your plan, no additional investment is needed for this from your end.
How many users come with each plan?
Every Kingmailer plan (free and paid) allows you to add as many users as you need to your account at no additional cost. We think it’s much easier this way to manage the account with your team, without sharing login credentials.
I want to test Kingmailer first. How can I do that?
The free trial is ideal for those looking to test out the service. Keep in mind that the free trial has a max 20 emails per hour limit and a max 20 recipients limit. If you reach these limits, your email traffic will be paused. The free plan has 30 days of log retention so you can easily troubleshoot issues.
If you’re a solo founder, an indie hacker, a bootstrapper, a webmaster, a developer or if you have multiple domains, and/or you need to manage multiple inboxes, then this article might be perfect for you.
We’ll show you how you can send and/or receive emails in your Gmail with your custom domain email addresses.
Here’s how to get started. If you need help, just send us an email info@kingmailer.co:
Create Endpoints
An Endpoint is where you want the emails to be delivered, it can be your Gmail-address. In your Kingmailer-account go to Routing (1), click on Address Endpoints (2) and then on Add your first address endpoint (3).
Enter your email address
Enter your email address (1) and click Create address endpoint (2).
Create a Route
The Endpoint is there, so now you can create any email address you like, all emails send to this address will be delivered (forwarded/routed) to the Endpoint aka your Gmail address.
Enter a username (1) for your email address for example info@domain so there you’ll enter just info. Select the domain (2) (which you already verified in your account: SPF, DKIM, MX and Return Path). Choose the Endpoint (3) which you created earlier.
Sending Emails from Gmail
Go to Settings > Accounts and Import > Add another email address > Send mail as
Add your email address
Enter your name and your email address, allow Treat as an alias and then Next Step
Enter the SMTP credentials
You can use these settings:
SMTP Server: kingmailer.org Username: enter your SMTP username Password: enter your SMTP password Port: 587, 465, 25 or 2525 Secure connection: TLS
So there you have it, you can send and receive emails in your Gmail using your own domain. Create as many email addresses you want, have the emails delivered to your Gmail, at no extra costs.
In this tutorial I have worked with Gmail, but you can use any other provider such as Hotmail, Yahoo or Proton etc.
If you are here, than you are probably already familiar with the concept of “transactional emails” or “application generated emails”, such as password reset emails, user registration emails, e-commerce emails and perhaps you are looking at what other options are out there.
We offer our SMTP service for sending, receiving and routing emails. You can also pay with Bitcoin.
Our goal is to provide you with a simple platform, easy to use. All accounts are screened and approved manually to maintain our high inbox.
Screenshots
Just go to give you an idea how our product looks like, we have included a few screenshots, swipe left to scroll:
Dashboard
DNS configuration
Troubleshoot email
This shows a list of outbound emails, you can also view the list of inbound emails, filter per email etc. Lots of nice options.
Emails /mo
Price /mo
Price /year
5,000
N/A
USD49
10,000
N/A
USD79
20,000
USD19
USD159
30.000
USD29
USD289
40,000
USD39
USD389
50.000
USD49
USD489
Pay with Bitcoin, Binance Pay, USDT or other cryptocurrency. Larger plans available. Please sign up and test our service first. Contact us info@kingsmtp.com or via Telegram @ KingSMTPcom
FAQ
How can I upgrade my account?
Send us an email to upgrade your account.
How does Kingmailer work?
Kingmailer is an email delivery and deliverability service that empowers businesses to easily send email from their (web) apps. It’s free to sign up and easy to get started.
How does your billing work?
You will be billed every 30 days. We accept PayPal and all major credit and debit cards. Your payment info is stored and processed securely by 2Checkout and never touches our servers.
How do I send emails with Kingmailer?
Since Kingmailer has both an HTTP API and an SMTP endpoint, you can choose to send the way you’d like. Both ways have their advantages… SMTP is easy to setup and often plug and play, but API is much more reliable at scale. If you’re building an application, we recommend using our HTTP API.
How many dedicated IP’s do I need? Can I get more?
You don’t actually need a dedicated IP when using Kingmailer, because great email delivery is already included in your plan, no additional investment is needed for this from your end.
How many users come with each plan?
Every Kingmailer plan (free and paid) allows you to add as many users as you need to your account at no additional cost. We think it’s much easier this way to manage the account with your team, without sharing login credentials.
I want to test Kingmailer first. How can I do that?
The free trial is ideal for those looking to test out the service. Keep in mind that the free trial has a max 20 emails per hour limit and a max 20 recipients limit. If you reach these limits, your email traffic will be paused. The free plan has 30 days of log retention so you can easily troubleshoot issues.
Kingmailer solves your spam (inbound or outbound filter) problem with its build-in Spam filter. Kingmailer uses SpamAssassin – an open source solution for combating email spam (unsolicited bulk spam).
Pay with Bitcoin, Binance Pay, USDT or other cryptocurrency. Larger plans available. Please sign up and test our service first. Contact us info@kingsmtp.com or via Telegram @ KingSMTPcom
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
Inbound filtering
Features
MailChannels
Kingmailer
Keeping up with spammers
✔
✔
30 minute support response, 24/7
✔
✔
Where did that email go?
email dashboard
email dashboard
FAQ
Does Kingmailer have Inbound filtering?
Yes. We have inbound filtering.
Does Kingmailer have outbound filtering?
Yes. We have outbound filtering.
How are emails filtered?
Our email servers have built-in SpamAssassin technology.
Pay with Bitcoin, Binance Pay, USDT or other cryptocurrency. Larger plans available. Please sign up and test our service first. Contact us info@kingsmtp.com or via Telegram @ KingSMTPcom
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
Their Essentials plan (cheapest what they offer, $14,95 p/mo), only gives 3 days of Search email activity… this can never be enough, forcing you to buy more days. A dedicated IP must be purchased (price $89,95 p/mo).
Kingmailer SMTP offers a simple interface and much much faster setup to start sending, receiving and routing emails.
This side-by-side comparison is based on features listed on Sendgrid’s pricing page:
Features
Sendgrid
Kingmailer
Straightforward Integration
SMTP and API
✓
✓
Interactive API Docs
✓
✓
Setup Guide
✓
✓
Comprehensive Client Libraries
✓
✘
Knowledge Center
✓
✘
Technical Support
✓
✓
Trusted Deliverability & Performance
Purpose-Built Mail Transfer Agent
✓
✓
Email Address Validation API
✘
✘
Globally Distributed Architecture
✓
Reputation & Delivery Visibility
✓
✓
Suppression Management
✓
✓
Dedicated IP Addresses
✘
✘
Automated, dedicated IP warm up
✘
✘
Dedicated IP Pooling
✘
✘
Domain Authentication (SPF/DKIM)
✓
✓
Link Branding
✓
✓
Reverse DNS
✘
✓
Universal Links
✓
✓
Actionable Analytics
Real-Time Analytics
✓
✓
Engagement Tracking
✓
✓
ISP Feedback Loop Data
✓
✓
Advanced Statistics
✓
✓
Subuser Comparison Statistics
✘
✓
Searchable Email Activity
3 days included
30 days included
Additional Email Activity History
Available for purchase
Available for purchase
Event Webhook
✓
✘
Inbound Parse Webhook
✓
✓
Expertise & Support
Technical Support
Ticket & chat support
Email, Facebook messenger, WhatsApp
Access to Expert Services
Available for purchase
✓
Dedicated Customer Success Manager
✘
✓
Productive Collaboration
Dynamic Templates
✓
✘
Email Content Testing
✘
✘
Teammate Permissions
1 team mate
✓
API Key Permissions
✓
✓
Subuser Management
✘
✓
Privacy & Security
Two-Factor Authentication
✓
✘
IP Access Management
✓
✓
TLS encryption
✓
✓
SOC 2 Type II certification
✓
✘
Privacy Shield Certification and GDPR Compliance
✓
✓
Contact us info@kingmailer.co
FAQ
How does Kingmailer work?
Kingmailer is a cloud-based SMTP provider that acts as an email delivery engine, allowing you to send email without the cost and complexity of maintaining your own email servers. Kingmailer manages the technical details of email delivery, like infrastructure scaling, ISP outreach, reputation monitoring, and real-time analytics.
How does the free trial work?
You can send 20 transactional emails to max 20 email recipients with your free account, which is perfect for testing purpose. If you need to send more than that, you can easily upgrade to a paid plan.
How do you measure the number of emails I send?
Every time you send one email to one recipient, it’s deducted as one email credit from your paid plan. This occurs whether the email is ultimately deferred or sent to spam by the inbox provider.
What happens if I go over my plan?
If you send more emails than your plan allows within a given billing period, you will be charged a small overage fee on a per-email basis. Any overage fees are added to your invoice for the following billing period.
Can you help me get started? Do you offer deliverability consulting?
Yes! We can walk you through the entire set-up process to ensure that your email environment is built for success. You don’t need deliverability consulting with Kingmailer as your emails are designed to land in user’s inboxes.
Why do I need to verify my account?
We only ask you do this by email, just click on the activation link to verify your account. No credit card is needed for this.
With Kingmailer you don’t need to purchase a dedicated IP or “managed email service” or pay extra for “great delivery” to enjoy great deliverability. Great email delivery is already included in your plan, doesn’t matter which plan you use. You can also pay with Bitcoin.
Try this Mailgun alternative for free.
Free clean IP address + email routing included. Not for mass mail or sending newsletters.
Pay with Bitcoin, Binance Pay, USDT or other cryptocurrency. Larger plans available. Please sign up and test our service first. Contact us info@kingsmtp.com or via Telegram @ KingSMTPcom
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
Side-by-side comparison
MailGun offers a free plan (Flex), which barely has any options, so we made the comparison with their Foundation plan, which costs $35 p/mo vs. Kingmailer’s $19.95 monthly plan (or $79 per year).
This side-by-side comparison is based on features listed on MailGun’s pricing page:
Features
Mailgun
Kingmailer
Email APIs, SMTP Relay, and Webhooks
✓
✓
Suppression Management
✓
✓
Inbound Email Routing
✓
✓
Email Tracking and Analytics
✓
✓
99.99% Guaranteed Uptime SLA
✓
✓
1 Dedicated IP
✘
✘
Email Address Validations
✓
✘
Inbox Placement Tests
✓
✓
Send Time Optimization
✘
✘
Log Retention
5 Days
30 Days
Message Retention
1 Day
30 Days
Detailed Documentation
✓
✓
24/7 Ticket Support
✓
✓
Instant Chat Support
✘
Facebook messenger
Live Phone Support
✘
✘
Managed Deliverability Services
✘
✓
Rapid Fire Burst Sending
✘
✘
Custom Features
✘
✓
Contact us support@kingmailer.co
FAQ
How can I upgrade my account?
Send us an email to upgrade your account.
How does Kingmailer work?
Kingmailer is an email delivery and deliverability service that empowers businesses to easily send email from their (web) apps. It’s free to sign up and easy to get started.
How does your billing work?
You will be billed every 30 days. We accept PayPal and all major credit and debit cards. Your payment info is stored and processed securely by 2Checkout and never touches our servers.
How do I send emails with Kingmailer?
Since Kingmailer has both an HTTP API and an SMTP endpoint, you can choose to send the way you’d like. Both ways have their advantages… SMTP is easy to setup and often plug and play, but API is much more reliable at scale. If you’re building an application, we recommend using our HTTP API.
How many dedicated IP’s do I need? Can I get more?
You don’t actually need a dedicated IP when using Kingmailer, because great email delivery is already included in your plan, no additional investment is needed for this from your end.
How many users come with each plan?
Every Kingmailer plan (free and paid) allows you to add as many users as you need to your account at no additional cost. We think it’s much easier this way to manage the account with your team, without sharing login credentials.
I want to test Kingmailer first. How can I do that?
The free trial is ideal for those looking to test out the service. Keep in mind that the free trial has a max 20 emails per hour limit and a max 20 recipients limit. If you reach these limits, your email traffic will be paused. The free plan has 30 days of log retention so you can easily troubleshoot issues.
Start sending, receiving, routing/forwarding your emails, using our free SMTP server. After signing up you will have your free SMTP Username and SMTP Password. And also free SMTP Web API.
Pay with Bitcoin, Binance Pay, USDT or other cryptocurrency. Larger plans available. Please sign up and test our service first. Contact us info@kingsmtp.com or via Telegram @ KingSMTPcom
Easy to troubleshoot emails
In your KingSMTP dashboard, you can click on each email to troubleshoot. KingSMTP logs and retains data of your emails, this is very useful when you need to troubleshoot your emails.
Here are a few screenshots to give you an idea:
Incoming messages
Spam check
Spam status
Extra details of your message
Spam Check details
Spam score
This is already pre-configured in your account, give it a try.
Kingmailer provides everything you’ll need for sending, receiving and routing (forwarding) your emails.
Time to Inbox ✔ System availability API ✔ Service availability API ✔
How does it work?
After signing up with Kingmailer you will have your own free SMTP mail server, with username and password. You can use the SMTP server and integrate with your web apps for example WordPress.
Why you will love KingSMTP
Kingmailer SMTP WordPress plugin
Quick email integration
Easy setup
Free plan
Highly reliable
Web API
Can also be used for inbound emails
Easy to use UI
Email + Telegram support
Easy to view logs of sent emails
Easy to configure in Gmail
Bitcoin also accepted
Have questions?
What payment methods do you accept?
We accept Bitcoin, Ethereum, Dogecoin, PayPal and all major credit and debit cards. Your payment information is stored and processed securely by 2Checkout and never reaches our servers.
Can I buy Transactional SMTP here?
Yes.
Can I use this SMTP service for sending mass / bulk mail?
No, we do not offer our service for sending mass / bulk mail.
Do you accept Bitcoin, Ethereum or Dogecoin?
Yes.
Will I have my own SMTP username and password?
Yes, after signing up, verifying your domain, your own SMTP username and password will be ready for you to use. All of your emails will be logged and easily viewed in your own email dashboard. You will also have your own Email API.
Can I use this with a WordPress SMTP plugin?
Yes. We also have our own WordPress plugin, just search Kingmailer SMTP in the WordPress directory. It works with our HTTP API.
Do I need to have a domain for this?
Yes. In order to be able to use our SMTP service, you will need to have your own domain. You will need to verify the domain and add a few DNS records (at least SPF and DKIM), before it’s good to go.
Do you offer forever free trials?
No. You can try the service for 14 days. No credit card required.
Can I ask for a refund?
Yes, no problem.
Will my emails go to the spam/junk folder?
We have a 99% inbox rate.
Can I send/receive emails in my email address?
Yes, this is possible. You will need to add our MX records to your DNS and configure routing. Don’t worry, we’ll help you with this.
Can I upload my list here and start emailing?
No. We do not provide a way for customers to upload their subscribers onto our platform.
