KingSMTP vs Postmark (2026): which should you pick?
As of Nov 12, 2026, Postmark grades higher than KingSMTP: 2.2 against 2.0 out of 4.0.
Checked Oct 18, 2026 and Nov 12, 2026 · graded Oct 18, 2026 and Nov 12, 2026 by ToolGPA
KingSMTP grades higher on value for money. Postmark grades higher on features and platforms. They get the same grade on the free plan and ease of use.
Price, platforms and features side by side. The table says where each price was read and when.
KingSMTP
SMTP relay you can pay for in crypto, with no KYC
Postmark
Transactional email API and SMTP, with broadcasts on a separate stream
Which one is for you
Pick KingSMTP if
- Fits if you want to pay in crypto without handing over ID
- Works for WordPress sites that want an SMTP relay and a plugin
Look elsewhere if
- 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
Pick Postmark if
- Fits if you want password resets kept on a separate stream from your newsletters
- Works for apps that need to look back at exactly what an email said weeks later
Look elsewhere if
- Pricey if you send 50,000 emails a month, at $55 with no yearly discount
- Skip it if you want a free plan to run a small app on, as it's 100 emails a month with no tier until 10,000
- Tight if you're on Basic, with 4 users, 5 sending domains and no inbound email
- Not for you if you want a dedicated IP below 300,000 emails a month, and each one is $50 a month on Pro or higher
- Watch out: DMARC reports are an add-on from $14 a month per domain
How we grade them
| 2.0GPAKingSMTPFair | 2.2GPAPostmarkFair | |
|---|---|---|
| Value for money | C$20 a month for up to 20,000 emails, which is where the dearer quarter of sending services starts. | DGraded on 50,000 emails a month: $55 on Basic or $60.50 on Pro, billed monthly only. That's the dearest in this category at that volume, roughly twice the middle. Bootstrapped companies can ask for $75 of credit. |
| Free plan and trial | CA 7-day trial on all plans with no credit card; there is no free plan after it. | CA free developer plan that never expires and needs no card, but it's 100 emails a month with no way to buy more. That's for testing an integration, not running an app. |
| Features | CSMTP 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. | BAPI and SMTP with SDKs, separate streams for app and bulk email, inbound email turned into JSON, templates, 45 days of message history and DMARC reports as an add-on from $14 a month. It covers the job; inbound needs Pro. |
| Ease of use | CNo 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. | CJudged on how fast a developer sends a first email: official SDKs, a sandbox mode, ready-made templates for resets and receipts, and migration guides. You'll still verify a domain first. No rating on record. |
| Platforms and integrations | CA web dashboard, an API and a WordPress plugin; WordPress is the one named integration. | BWeb, with an API and SMTP, plus Zapier, WordPress, Stripe, Slack, Supabase, Bubble, Netlify and Datadog. No desktop or phone app, so B is the top. |
| Best for | paying for SMTP in crypto with no ID check | app email kept apart from marketing sends |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: KingSMTP and Postmark. How we grade
Price against what you get
KingSMTP starts at $20 a month and scores 2.0 out of 4 on features, ease of use and platforms. Postmark starts at $15 a month and scores 2.7.
Postmark scores higher and starts $5 a month lower. Of the other email sending services on the chart, 17 score higher than KingSMTP for less, and none scores higher than Postmark for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- Postmark also covers dMARC.
At a glance
| KingSMTP | Postmark | |
|---|---|---|
| Pricing | Free trial | Free plan |
| Starts at | $20 per month for up to 20,000 emails | $15 per month for 10,000 emails |
| Free plan | None | Free developer plan: 100 emails a month with no expiry and no overages, for testing an integration or a small side project. No credit card needed. |
| Free trial | 7-day free trial on all plans, no credit card required | None listed |
| Web | ||
| Made by | KingSMTP | ActiveCampaign, LLC |
| Price read from | kingsmtp.com | postmarkapp.com |
| Checked | Nov 12, 2026 | Oct 18, 2026 |
Worth knowing
KingSMTP
- 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.
Postmark
- There is no tier between the free 100 emails a month and the 10,000-email paid plans.
- Billing is monthly only; the FAQ says annual plans are not offered yet.
- Basic has no inbound email processing and caps users at 4 and sending domains at 5.
- Dedicated IPs start at $50 a month per IP, need Pro or higher and 300,000 emails a month or more.
Key features
KingSMTP
- 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.
Postmark
- Email API and SMTP
- Send through a REST API with official SDKs or through SMTP, with batch sending, a sandbox mode and migration guides from other providers.
- Message streams
- Transactional and bulk or broadcast email run on separate sending infrastructure, so marketing sends do not affect password resets and receipts.
- Inbound email processing
- Pro and Platform turn incoming email into a JSON object and post it to a webhook URL your app handles.
- Templates
- Responsive templates for welcome emails, password resets and receipts, with a template editor and import tool.
- Message history and analytics
- 45 days of full message content by default, adjustable from 7 to 365 days, with bounce details, open and link tracking and a stats API.
- DMARC monitoring
- DMARC Digests reports show authentication problems and who is sending with your domain, sold as an add-on from $14 a month per domain.
Plans
KingSMTP
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.
Postmark
Free$0
100 emails a month, never expires; extra emails cannot be bought on this plan.
Basic$15
per month for 10,000 emails
5 sending domains, 4 users, 45 days of history, no inbound email. Extra emails $1.80 per 1,000; $55 a month at 50,000 emails.
Pro$16.50
per month for 10,000 emails
10 domains, 6 users, inbound email, retention up to 365 days. Extra emails $1.30 per 1,000; $60.50 a month at 50,000 emails.
Platform$18
per month for 10,000 emails
Unlimited domains, servers, streams and users, with inbound email. Extra emails $1.20 per 1,000; $66 a month at 50,000 emails.
High volumeCustom
Custom pricing for large senders, arranged through sales.
Ways to pay less
KingSMTP
- 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.
Postmark
- Startups
$75 credit for bootstrapped companies
Companies that have launched, are charging for their product and have taken no outside investment can ask support for $75 of account credit.
Common questions
Which is cheaper, KingSMTP or Postmark?
As of Nov 12, 2026, Postmark is cheaper to start with: $15 a month, against $20 a month for KingSMTP. KingSMTP starts at $20 per month for up to 20,000 emails, and Postmark starts at $15 per month for 10,000 emails.
Which has a free plan, KingSMTP or Postmark?
As of Nov 12, 2026, only Postmark has a free plan. KingSMTP does not, though it has a free trial.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.