SendPost Review 2026: A Free Plan on One Page, a Demo Wall on the Other

The short version

SendPost is the smallest platform on this site by public evidence. Three Capterra reviews, three G2 reviews with none of them rendered, no Trustpilot listing, no Product Hunt page, no Reddit thread we could find. That is six reviews in total, of which we were able to read three.

What is there is technically solid. The SMTP reference publishes a hostname, four ports and the encryption mode for each, which is more than Campaign Monitor, Selzy or Sendloop manage. The API publishes a base URL, an authentication header and real endpoints. There are 43 public repositories on GitHub, including fourteen framework example projects all updated on the same January 2026 day. There is a SendGrid-compatible endpoint that lets you point an existing integration at SendPost by changing a URL.

What is not there is the thing a buyer needs first. SendPost does not publish a price. Not a plan name, not a tier, not a number. The pricing page shows a Schedule Demo button in three places and nothing else. And on the two vendor pages that answer the question “Do you offer a free plan or trial?”, the answers are opposite.

Two answers to the same question

SendPost is marketed from two surfaces: its own site at sendpost.io, and a set of pages hosted on sendx.io. Both carry a FAQ. Both FAQs ask the same question. The answers do not match.

We read both pages twice, on the same URLs, demanding the literal surrounding text on the second pass. Both strings are real. On the first page, the words free forever and 25,000 do not appear at all.

Capterra’s listing shows “Starting price $7 Usage Based, Per Month”. That figure appears nowhere in SendPost’s own materials. It is third-party reported and we do not repeat it as a price.

Snapshot

The SMTP setup, which is the best documented thing here

This is where SendPost is unambiguously good, and it is worth saying plainly because so few providers at this size are. The API reference publishes a hostname, every port, and what each port is for.

We read that page three times because we have been burned once already in this project by a summariser inventing a table of SMTP settings that did not exist. These values reproduce literally on every read.

The API, and the two things it does not publish

The base URL is https://api.sendpost.io/api/v1, corroborated independently by the README of the JavaScript SDK. Sub-account authentication uses the header X-SubAccount-ApiKey. Sending is a POST to /subaccount/email/. Real-time webhooks are documented.

Two things are missing and both matter.

There are no published rate limits. Not for the API, not for SMTP, not per sub-account. For a transactional provider this is the number an engineer needs before writing a retry policy. MailerSend publishes every one of its limits; SendPost publishes none.

There is no MCP server. We enumerated all 43 public repositories and none carries the name. Nothing in the documentation references the protocol.

The migration APIs, one confirmed and one that is not what it sounds like

The SendGrid-compatible API is real. It lives at https://api.sendpost.io/v1/sendgrid/v3/mail/send, described as “Migrate from SendGrid with minimal code changes using SendPost’s SendGrid-Compatible API.” If you have a SendGrid integration in production, that is a genuine one-line move, and given what has happened to SendGrid accounts without notice it is a sensible thing to build.

An Amazon SES compatible API is often attributed to SendPost and we could not confirm it. The documentation path for it returns 404, and the string does not appear on the SES page. What exists is an integration that routes through an IP pool parameter. That is not the same thing, and we are not describing it as one.

SDK count, which the vendor gives two answers to

The documentation says “SDKs in 6 programming languages”, and six is what the current repositories show: JavaScript, Python, Go, Ruby, Java and PHP. The pricing page says “SDKs in 14+ programming languages”. Both are on vendor surfaces. Six is the number we can count.

A detail worth noting for anyone integrating: the documentation writes the account-level header as both X-Account-APIKey and X-Account-ApiKey on the same page, and the example API key is printed in the clear. Neither is dangerous. Both are the kind of thing a documentation pass catches.

Is anyone still building it

Yes, and the GitHub record is the clearest evidence in this review because it is dated and public.

That is a real, funded engineering push followed by a long quiet stretch. It is not the profile of an abandoned product, and it is not the profile of one under continuous development either. The old java SDK, incidentally, was never archived alongside its five peers, which is the sort of loose end that tells you the clean-up was done by hand and not finished.

Three reviews, and what we can honestly say from them

Capterra shows 5.0 from 3 reviews. We read all three. G2 shows 4.7 from 3 reviews and renders none of them, so we read zero of those and can quote nothing from G2. Trustpilot has no listing for sendpost.io. Product Hunt has no page.

Support is named positively in two of the three rendered rows. Company size is displayed for none of them. The newest review is from May 2024, which makes the corpus roughly twenty-seven months old.

Deliverability, where every number is the vendor’s own

SendPost is not in the EmailToolTester seedlist panel, which was frozen in January 2024 and has since been discontinued in favour of feature assessments. It has no page on emaildeliverabilityreport.com. There is no independent measurement of SendPost inbox placement anywhere that we could find.

What the vendor publishes about itself:

• “SendPost maintains 95-98% delivery rates and maintained its deliverability team size at only 3 people.”
• “95-98% inbox placement even as volume scaled from 100M to 300M emails per month”

Those are two different metrics. Delivery rate counts messages the receiving server accepted. Inbox placement counts messages that landed in the inbox rather than the spam folder. They are never the same figure, and a provider that quotes one identical range for both has not measured them separately.

Volume is quoted three different ways across the same family of pages: “Sending over 413+ million emails per month”, “over 300 million emails/month” for SendX, and “100M to 300M” in the case study. These may all be true of different entities at different dates. Read together on one afternoon, they are three numbers for one claim.

The infrastructure story is better than the numbers. Shared or dedicated IPs, automatic IP warmup, real-time bounce and complaint handling, alerting, and a deliverability team that came out of an ESP doing serious volume. That is why the score below is 5.5 and not lower. It is not 7 because nothing here has been checked by anyone outside the company.

What is not published at all

Collected in one place, because for a provider aimed at businesses these absences are the buying risk:

Log retention is published, and it is the one operational number they do give: “Email Event Logs Uncover exactly what happened to your emails – with full transparency, search, and retention for up to a year.” Note the words up to. That is a ceiling, not a guarantee, and it is almost certainly plan-dependent, which we cannot check because there are no plans published.

Ratings breakdown

Ease of use, 6.5. The documentation is clear, there are fourteen framework starters to copy from, and the two usable reviews both praise onboarding. Held down because you cannot sign up and try it: the front door is a demo request.

Automation, 5.5. This is a transactional relay, not a marketing platform, and it is scored as one. Templates with Handlebars, AMP support, groups, sub-accounts and real-time webhooks are all present. There is no campaign builder, no segmentation, no journey editor, and none is claimed.

Deliverability, 5.5. Good infrastructure, an experienced team, dedicated IPs with automatic warmup. Zero independent verification, two incompatible metrics quoted with one range, three different volume figures, and no compliance certification of any kind.

Support, 6.5. Named positively in two of the three rendered Capterra rows, one of them specifically for speed of resolution. Held down because the corpus is three reviews old enough to be historical, there is no status page, and no support SLA is published.

Pricing value, 4.5. The lowest score we have given in this category. There is no price. There is no plan. The one page that promises a free forever tier is contradicted by the page the vendor calls its pricing page. You cannot assess value against an unpublished number, and a buyer should not have to book a call to learn the shape of the offer.

API and MCP, 6.5. Base URL, auth header, webhooks, six SDKs, a working SendGrid-compatible migration endpoint and a genuinely complete SMTP reference. Held down by unpublished rate limits, no MCP server, an SES-compatible API that does not exist as described, and inconsistent header casing in the docs.

Who should use SendPost, and who should not

Third-party validation

We never add Capterra and G2 into a single denominator. Where this review says something is named by reviewers, it means named in that many of the three rendered Capterra rows.

Top 3 alternatives

Continue reading

• SendPost pricing, and why there is nothing to quote
• SendPost API, endpoints, headers and the SendGrid-compatible route
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• MailerSend review
• SMTP2GO review

Frequently asked questions

What is SendPost?

A transactional email API and SMTP relay, marketed as a product of SendWorks and built by the engineering team behind SendX. The legal entity is SendPost, LLC of Denver, Colorado, doing business as SendWorks and SendX, governed by Delaware law. It is aimed at developers and at platforms that send on behalf of their own customers, not at marketers building campaigns.

How much does SendPost cost?

We cannot tell you, because SendPost does not publish a price. Its pricing page contains no plan name, no quota and no dollar figure, only a request to schedule a demo. One vendor FAQ states that a demo and an up front financial commitment are required. Capterra shows a starting price of $7 per month on a usage basis; that figure appears nowhere in SendPost’s own materials and we do not repeat it as fact.

Does SendPost have a free plan?

The vendor gives two opposite answers to that exact question on two of its own pages. One says no free plan or trial is offered and a demo with an up front commitment is required. The other says there is a free forever plan of up to 25,000 emails a month with no credit card. The canonical pricing page publishes neither. Treat the free tier as unconfirmed and ask for it in writing.

What are SendPost’s SMTP settings?

The hostname is smtp.sendpost.io. Ports 25, 2525 and 587 are for unencrypted or TLS connections, with STARTTLS supported, and port 465 is for SSL. The vendor recommends 587. Authentication uses the username and password from your account; the AUTH mechanism is not named, and no per-connection message limit or rate limit is published anywhere.

Is SendPost a good SendGrid alternative?

Technically it is set up to be one. There is a SendGrid-compatible endpoint at api.sendpost.io/v1/sendgrid/v3/mail/send, described by the vendor as letting you migrate with minimal code changes, and one of the three Capterra reviews is titled exactly that. The reservation is commercial rather than technical: SendGrid publishes its prices and SendPost does not.

Is SendPost still being developed?

Yes, though not continuously. Its GitHub organisation holds 43 public repositories, with an entire SDK generation rebuilt in late December 2025 and fourteen framework example projects all updated on 15 January 2026. Nothing public has changed since then, roughly seven and a half months. There is no status page and no changelog, so GitHub is the only dated liveness signal available.

Changelog