The KingSMTP Insider’s Guide
Everything we know about KingSMTP in one document: what it costs, its grades, getting a refund, getting help and what else to look at. Read it here, or keep a copy.
KingSMTP
The Insider’s Guide
SMTP relay you can pay for in crypto, with no KYC
Every plan, grade, refund rule and rival among email sending services, read from KingSMTP’s own pages.
Made by KingSMTP · checked Nov 12, 2026 · toolgpa.com
Contents
- 01WelcomeWhat it is, who it suits, its grades and the ten things to know first
- 02What it costsEvery plan, the free plan, ways to pay less and how prices have moved
- 03What it doesIts main features, where it runs, what it works with and who makes it
- 04Where it standsIts grades against its category, and whether to keep it or make your own
- 05The alternativesThe tools it is most often weighed against, side by side
- 06Quick answersThe questions people ask about it, each answered in a line or two
- 07About ToolGPAWho made this guide, what else is on the site, and how to cite it
ToolGPA put this guide together from KingSMTP’s own pages, its app-store listings and our grades. Every fact in it is on KingSMTP’s page too, where it is kept up to date. Checked Nov 12, 2026.
Part 01 · Overview
Welcome
What it is, who it suits, its grades and the ten things to know first
2.0
GPA, above 2 of the 26 other email sending services we grade
KingSMTP is a privacy-focused SMTP relay and HTTP API for transactional email, run by an independent, bootstrapped team that says it launched in 2017. Its pages say there is no identity verification at sign-up and that it does not scan or sell message content. Plans are priced by monthly email volume, and the pricing page lists Bitcoin, USDT and Monero.
To get you started, here are 9 things to know about KingSMTP, taken from its own pages and our grades.
You verify a sending domain with DNS records and wire up SMTP credentials or an API key before the first email goes out.
- 1
Best for paying for SMTP in crypto with no ID check
KingSMTP is an SMTP relay and HTTP API that takes crypto payment and says it asks for no ID.
- 2
Paid plans start at $20 a month
As its pricing page puts it: $20 per month for up to 20,000 emails.
- 3
You can try it first
7-day free trial on all plans, no credit card required
- 4
It runs on Web
Web.
- 5
SMTP and HTTP API
Connect an app, CMS or WordPress site through SMTP or the HTTP API, with DKIM and SPF included.
- 6
Per-email dashboard
Shows delivery status, spam scores, headers and the full SMTP transaction log for each message.
- 7
Crypto payment, no KYC
The site lists Bitcoin, USDT and Monero and says sign-up needs no identity verification.
- 8
A 2.0 GPA, above 2 of 26
That is against the other email sending services we grade, on value, the free plan, features, ease of use and platforms.
- 9
Keep it
To replace KingSMTP you would be making mail servers with a good name among inbox providers. That is not a weekend's work, with an AI app builder or without one.
KingSMTP at a glance
- Pricing
- Free trial, from $20 per month for up to 20,000 emails
- Free plan
- No
- Free trial
- 7-day free trial on all plans, no credit card required
- Runs on
- Web
- Made by
- KingSMTP, since 2017
- Category
- Email Sending Services
- Our grade
- 2.0 GPA, fair
The report card
Best for paying for SMTP in crypto with no ID check
KingSMTP is an SMTP relay and HTTP API that takes crypto payment and says it asks for no ID. It starts at $20 a month for 20,000 emails after a 7-day trial, but there is no free plan, only a shared IP option is listed, and the privacy claims are the vendor's own words.
| Subject | Grade | Comment |
|---|---|---|
| Value for money | C | $20 a month for up to 20,000 emails, which is where the dearer quarter of sending services starts. |
| Free plan and trial | C | A 7-day trial on all plans with no credit card; there is no free plan after it. |
| Features | C | SMTP and an HTTP API, a per-email dashboard, inbound routing and a WordPress plugin, but only a shared IP option and no dedicated IP in the listing. |
| Ease of use | C | No store rating on record. You verify a sending domain with DNS records and wire up SMTP credentials or an API key before the first email goes out. |
| Platforms and integrations | C | A web dashboard, an API and a WordPress plugin; WordPress is the one named integration. |
An A is worth 4 points, a B 3, a C 2, a D 1 and an F nothing. The GPA is the average of the five.
Who KingSMTP is for
- Fits if you want to pay in crypto without handing over ID
- Works for WordPress sites that want an SMTP relay and a plugin
Who it is not for
- Skip it if you need a dedicated IP, as only shared IPs are listed
- Tight if you send over 100,000 emails a month, because the plans stop there and the rest is a custom plan
- Watch out: the pricing page lists crypto payment and does not say whether cards are accepted
- Watch out: the no-ID and no-scanning claims are the vendor's own statements
- Skip it if you want a free plan, since there is only the 7-day trial
Good to know
Good for
- Senders who want to pay in cryptocurrency
- Small apps and WordPress sites that need a simple SMTP relay
- People who want to avoid identity checks at sign-up
Worth knowing
- The pricing page lists crypto payment; it does not say whether cards are accepted.
- Volume is capped per plan at 20,000, 50,000 or 100,000 emails a month; anything more is a custom plan.
- Plan feature lists mention a shared IP option, and no dedicated IP is listed.
- The no-KYC and no-scanning claims are the vendor's own statements.
Part 02 · Pricing
What it costs
Every plan, the free plan, ways to pay less and how prices have moved
$20
A month to start
KingSMTP is a paid product with a free trial, starting at $20 per month for up to 20,000 emails.
Starter
$20
per month for up to 20,000 emails
Full SMTP, HTTP API, email and Telegram support, and crypto payment.
Business
$50
per month for up to 50,000 emails
Adds MX routing for inbound, priority support, an analytics dashboard, a WordPress plugin and a shared IP option.
Growth
$100
per month for up to 100,000 emails
Adds shared IP, a custom domain and advanced analytics. Higher volumes are by custom plan.
Trying it first
7-day free trial on all plans, no credit card required
Read from kingsmtp.com on Nov 12, 2026.
Ways to pay less
Annual discount
Two months free with yearly billing
The pricing page shows yearly prices of $200, $500 and $1,000 for the three plans and labels them Save 2 months.
Stated on kingsmtp.com
Part 03 · Features
What it does
Its main features, where it runs, what it works with and who makes it
1
Place it runs: Web
SMTP relay you can pay for in crypto, with no KYC. Here is what it does, as its own site describes it, and what it covers: public API, transactional email.
A web dashboard, an API and a WordPress plugin; WordPress is the one named integration.
- SMTP and HTTP API
- Connect an app, CMS or WordPress site through SMTP or the HTTP API, with DKIM and SPF included.
- Per-email dashboard
- Shows delivery status, spam scores, headers and the full SMTP transaction log for each message.
- Crypto payment, no KYC
- The site lists Bitcoin, USDT and Monero and says sign-up needs no identity verification.
- Inbound routing
- Business and Growth add MX routing for inbound mail.
- WordPress plugin
- A KingSMTP plugin is available from the WordPress directory and is included from the Business plan.
Where it runs
- Web
What it works with
- WordPress
KingSMTP is made by KingSMTP, and has been around since 2017.
Part 04 · Standing
Where it stands
Its grades against its category, and whether to keep it or make your own
2/26
Other email sending services it is graded above
KingSMTP's GPA of 2.0 is higher than 2 of the 26 other email sending services we grade, and level with 1.
Its paid plans start at $20 a month, against a middle price of $13.73 for the category: 20 of the 25 others that charge start lower.
On features, ease of use and platforms it scores 2.0 out of 4. 17 tools score higher and cost less.
Each grade against the category
Every bar is all 27 email sending services we grade, cut by the letter each got. KingSMTP’s own letter is outlined.
- CValue for moneyAbove 3 of 26
- CFree plan and trialAbove 4 of 26
- CFeaturesAbove 0 of 26
- CEase of useAbove 1 of 26
- CPlatforms and integrationsAbove 0 of 26
Price against what you get
Each dot is one of 26 email sending services. Further left costs less; higher up scores better on features, ease of use and platforms. KingSMTP is the marked dot.
What paid plans start at, a month (each step along is roughly double) →
Keep it, or make your own?
Whether this is something you could build for yourself with an AI app builder, and what you would give up.
Keep it
To replace KingSMTP you would be making mail servers with a good name among inbox providers. That is not a weekend's work, with an AI app builder or without one.
That makes this kind of software worth paying for, not this one in particular: 23 of the 26 other email sending services grade higher. It costs $240 a year.
What you could not
- Mail servers with a good name among inbox providers.
- It plugs into other products, WordPress among them, and has an API.
What this rests on. KingSMTP’s listing: what it does, where it runs, what it plugs into and what it costs. It is a judgement about the kind of software this is. We have not built a replacement for it, and making your own means looking after it too. How we decide, and every tool’s verdict.
Part 05 · Alternatives
The alternatives
The tools it is most often weighed against, side by side
SMTP2GO, turboSMTP, SMTP.com, Postmark and Mailgun
The 5 tools KingSMTP is most often weighed against, with where each one differs from it.
- 2.2GPA
SMTP2GO
Free plan · from $15/mo
SMTP relay and email API priced by emails a month, with a free plan.
- SMTP2GO has a free plan. KingSMTP does not, though it has a free trial.
- 2.2GPA
turboSMTP
Free plan · from $12.46/mo
SMTP relay and email API on European infrastructure, with a free plan.
- turboSMTP has a free plan. KingSMTP does not, though it has a free trial.
- turboSMTP also covers email verification.
- 1.8GPA
SMTP.com
From $25/mo
SMTP relay and email API sold in monthly volume plans from 50,000.
- 2.2GPA
Postmark
Free plan · from $15/mo
Transactional email API and SMTP, with broadcasts on a separate stream.
- Postmark has a free plan. KingSMTP does not, though it has a free trial.
- Postmark also covers dMARC.
- 2.4GPA
Mailgun
Free plan · from $15/mo
Email API and SMTP relay for developers, with list validation.
- Mailgun has a free plan. KingSMTP does not, though it has a free trial.
- Mailgun also covers email verification.
Part 06 · Questions
Quick answers
The questions people ask about it, each answered in a line or two
14
Questions, each answered in a line or two
The short version of everything above, for when you only need the answer. Each one is told in full in its part of the guide.
Is KingSMTP free?
No, KingSMTP is a paid product, but you can try it first. 7-day free trial on all plans, no credit card required.
How much does KingSMTP cost?
KingSMTP lists 3 plans. Starter: $20 per month for up to 20,000 emails.
What platforms does KingSMTP work on?
KingSMTP is available on Web.
Does KingSMTP offer any discounts?
KingSMTP publicly lists the following: Two months free with yearly billing.
Does KingSMTP have an Android app?
No Android app was listed when its pages were read on Nov 12, 2026. KingSMTP is listed for Web.
Does KingSMTP have an iPhone app?
No iPhone app was listed when its pages were read on Nov 12, 2026. KingSMTP is listed for Web.
Is KingSMTP open source?
KingSMTP is not described as open source on its own site, as read on Nov 12, 2026.
Does KingSMTP have an API?
Yes. KingSMTP offers a public API, according to its own site.
What does KingSMTP integrate with?
KingSMTP's listing names WordPress. A listing names up to eight integrations, so it may connect to more.
Who makes KingSMTP?
KingSMTP is made by a company of the same name. It dates from 2017.
What are the alternatives to KingSMTP?
The closest alternatives to KingSMTP in our directory are SMTP2GO, turboSMTP, SMTP.com, Postmark and Mailgun.
How does KingSMTP compare with other email sending services?
KingSMTP's GPA of 2.0 is higher than 2 of the 26 other email sending services we grade, and level with 1.
Is KingSMTP good value for money?
ToolGPA grades KingSMTP C for value for money. On features, ease of use and platforms it scores 2.0 out of 4.
Could I make my own version of KingSMTP?
To replace KingSMTP you would be making mail servers with a good name among inbox providers.
Where this guide comes from
The prices, plans, platforms and features were read from KingSMTP’s own pages on Nov 12, 2026, and the grades were given on Nov 12, 2026. Graded from this listing, whose facts were read from KingSMTP's own pages on 12 November 2026. Not based on using the product, and shorter than our full reviews.
Every tool we list gets five grades, A to F, each with its reason, and a GPA that averages them. How each is decided is at toolgpa.com/grades. This guide is ToolGPA’s own work; it is not made, paid for or approved by KingSMTP. Prices change, so check kingsmtp.com before you buy.
Part 07 · About
About ToolGPA
Who made this guide, what else is on the site, and how to cite it
5,038
Tools graded, in 95 categories
ToolGPA grades software the way a school report grades a pupil: five subjects, a letter for each with the reason written beside it, and a GPA that averages them. Prices, plans and platforms are read from each maker’s own pages and dated, so you always know how fresh a figure is.
Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. Every tool on the site has a guide like this one, free to download and pass on. It all lives at toolgpa.com.
5,038
tools graded
95
categories
739
price changes on record
579
apps priced in 12 countries
What else is on toolgpa.com
- KingSMTP, kept up to dateEverything in this guide, with prices and grades as they are todaytoolgpa.com/tools/kingsmtp
- How grades are givenThe rules behind every letter and every GPAtoolgpa.com/grades
- Value chartsWhat each tool costs against what it scores, for every categorytoolgpa.com/charts
- CompareAny two tools side by side, plan by plantoolgpa.com/compare
- Price changesEvery price rise and cut on record, each with its sourcetoolgpa.com/price-changes
- Prices by countryWhat apps cost on the App Store in 12 countriestoolgpa.com/prices-by-country
- Pay lessEvery public discount: yearly billing, students, nonprofitstoolgpa.com/save
- Keep or makeWhich tools are worth paying for, and which you could build yourselftoolgpa.com/keep-or-make
Scan for the live page
Prices and grades as they are today
Quoting this guide?
Please name ToolGPA and link to the live page, so readers can check the figures for themselves:
ToolGPA, "KingSMTP: The Insider's Guide", checked Nov 12, 2026. https://toolgpa.com/tools/kingsmtp
Know someone choosing between email sending services?
Send them this guide: toolgpa.com/tools/kingsmtp/guide
ToolGPA elsewhere: youtube.com/@toolgpa
See our other guides
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- Amazon SES Insider's GuideAWS email sending and receiving, paid per 1,000 emails2.8 GPA
- Forward Email Insider's GuideOpen-source email forwarding and hosting for custom domains2.8 GPA
- MailChannels Insider's GuideEmail API and SMTP relay for platforms with many downstream senders2.8 GPA
Choosing software? Every tool graded, every price dated.
Compare tools at toolgpa.com ›Everything in this guide is ToolGPA’s own summary of what KingSMTP’s pages, its app-store listings and public reviews said on the dates shown. Grades are our judgement under the rules at toolgpa.com/grades. Every grade, review and ranking on ToolGPA is our own judgement. No company can pay for a grade or change one. KingSMTP is a trademark of its owner, and this guide is not made, paid for or approved by KingSMTP. Prices and plans change: check kingsmtp.com before you buy.