Nitrosend vs Sender.

Unlimited contacts, priced on sending, agent-native, and a published price at scale.

TL;DR

Sender is subscriber-priced email marketing for small senders. Campaigns, automation, signup forms, popups, landing pages, and transactional email sit in one subscription, and the free tier runs to 2,500 subscribers and 15,000 emails a month with no card. If your list and your send volume track each other, that bundle is the argument, and it's a good one. Where it stops being one is the question our comparison index keeps returning to.

Nitrosend specializes in email and prices on what you send, so contacts never enter the bill. On Sender the subscriber tier you buy is also your send allowance: twelve times the list in monthly credits on Standard, twenty-four on Professional. Sender has a real, documented API of its own. The difference is what an agent can reach through it, because here the email API and the MCP tools cover the same surface.

Pricing math

What you actually pay.

The two ladders bill on different things. Sender charges for subscribers and derives the monthly email allowance from that tier, and we charge for the emails you send, so each scenario carries both a list size and a send volume. The right-hand column is Sender's published ladder rate at that subscriber tier. Annual billing is discounted against it. Sender is cheaper at 2,500 contacts, and the two only cross once the list grows away from the sending.

Scenario	Nitrosend	Sender
Free	8,000 emails to start, then 500/mo forever. Unlimited contacts, 1 seat, full MCP, API, and CLI	2,500 subscribers and 15,000 emails/mo, 1 seat, transactional included, and Sender branding stays on every send
2,500 contacts, 20,000 emails/mo	$20 Pro: 20,000 emails, 3 seats, BYO sending and AI keys	$19 Standard: 2,500 subscribers with 30,000 email credits and 3 seats. Advanced automation starts on Professional at $35
50,000 contacts, 100,000 emails/mo	$100 Ultra: 125,000 emails, 5 brands, 10 seats. Contacts never enter the price	$227 Standard at the 50,000-subscriber tier, whether or not you mail them
500,000+ emails/mo	$300 Enterprise: 500K to 4M+ emails at a published price, with SSO and SAML	Enterprise, custom price behind a demo, and the only tier carrying unlimited sending and SSO

Prices accurate as of August 2026. Check vendor sites for current rates.

Migration

How to switch (or run both).

Sender keeps sending while you move, and the forms, popups, and landing pages you built there stay where they are until you're ready.

Add and verify your sending domain in Nitrosend. SPF and DKIM records sit alongside Sender's, so both platforms can send from the same domain for as long as the overlap lasts.
Filter first, then export. Sender's export runs off whatever filter is on screen, so pull one group at a time rather than one file for everything. CSV and XLSX both come out, and nitro_import_contacts takes either: groups map onto lists and custom fields onto custom fields.
Pull engagement history out of the campaign reports rather than the subscriber export. Sender exports recipients by engagement category, including opens, clicks, and unsubscribes, and that history is what a segment on the other side gets built from.
Move one transactional message type first. A receipt or a password reset through nitro_send_message, watched for a week before a campaign follows it. Sender's own API keeps sending the rest meanwhile, so nothing is cut over on faith.
Decide what carries your reputation. BYO sending keys on Pro and above route mail through Amazon SES, Resend, Postmark, Mailgun, or SendGrid. Sender's own pool isn't one of them, so a sender leaving its shared pool is warming a new path whichever platform it lands on. What travels with you is the domain and its authentication history.

Honest credit

What Sender does well.

Picking a tool is about fit. Here's what Sender is genuinely good at.

A free tier a real sender can work on: 2,500 subscribers, 15,000 emails a month, automation included, and no card.
Transactional email is part of the same product on every plan including Free, rather than a second subscription somewhere else.
Both transports are there: a REST endpoint and an SMTP relay for the systems that only speak SMTP.
Webhooks cover delivery, bounce, open, click, and complaint events, and every payload is verified against a signing secret.
Bounce and complaint handling is automatic, so the list cleans itself without a second tool.
A documented REST API with Bearer token auth and code examples in Node.js, Python, PHP, Ruby, Java, Go, and .NET.
API tokens are self-serve, with published rate limits and a 429 rather than silent throttling.
Signup forms, popups, and landing pages come with the subscription rather than as paid add-ons.
The price ladder is published all the way to 50,000 subscribers, so the bill at your next list size is knowable before you commit.

What Nitrosend adds

Where we think we're better.

Unlimited contacts on every plan, including Free, so a list that grows without being mailed never moves the bill.
We price on the emails you send, so 50,000 addresses mailed twice a month costs what the sending costs.
On Sender the subscriber tier is also the send allowance: twelve times the list in monthly credits on Standard, twenty-four on Professional.
A small list mailed hard has to buy subscriber tiers it doesn't have, and a large list mailed rarely pays for addresses it never touches.
When Sender's monthly credits run out, campaign sending stops until the cycle resets.
A published price from 500,000 to over 4,000,000 emails a month, where the ladder usually turns into a demo booking.
MCP-first is an architecture, not an integration: every capability at Nitrosend is an API endpoint and an MCP tool before it's a screen.
Sender's agent route runs through a third-party connector, so what an agent reaches is what that connector exposes rather than the platform itself.
BYO sending keys on Pro and above route your mail through Amazon SES, Resend, Postmark, Mailgun, or SendGrid, on the domain and IP you already warmed.
Bringing your own keys makes the move reversible, and switching platforms otherwise means switching sending reputation on the same day, when the two failures look identical.

Use case fit

When to pick which.

Pick Sender if

Your list and your send volume track each other, so a subscriber tier that carries twelve times the list in credits is simply your bill. You want SMS against the same contact record, or popups, signup forms, and landing pages inside one subscription rather than three. Being under 2,500 subscribers, with free forever as the whole requirement, points the same way. None of those are close calls.

Pick Nitrosend if

Email is the channel your program runs on, and your list is much larger than your send volume or much smaller than it. Either way, you'd rather the bill tracked the sending. It's the right call too when transactional and campaigns belong on one bill with nobody else's branding on the free tier, or when you want the platform to answer to an agent end to end, including domain authentication, deliverability, billing, and the approval step. The nearest alternatives on price shape are SendGrid and SendLayer on the send-metered side, and Sendy if a self-hosted licence is on the table.

Sender vs Nitrosend - common questions.

Can Nitrosend replace Sender?

For the email half, yes. Campaigns, automation, segments, templates, contacts, and transactional sending are all here, and transactional arrives on the same bill rather than as a separate product. The part that isn't a swap is the surface: Sender's API is a developer integration point, and Nitrosend is an AI-native email platform, so campaigns, flows, segments, and templates are things an agent runs rather than things a person clicks. Sender keeps the channels and the capture tools it was built for, so a team using it as its signup layer as well as its ESP is splitting two jobs that were one. Work out which of those you're actually buying before you move.

Is Nitrosend cheaper than Sender?

It depends which axis you're on. At small list sizes Sender is cheaper on paper: $19 a month at 2,500 subscribers, carrying 30,000 email credits, against $20 Pro for 20,000 emails. The comparison inverts as the list grows away from the sending, because $227 buys the 50,000-subscriber tier whether or not you mail it, and $100 Ultra buys 125,000 emails whatever the list is.

Can I keep sending transactional email after I move?

Yes, and it's the easiest thing to move first. Point one message type at Nitrosend's nitro_send_message agent command on a verified domain, leave the rest on Sender's API for a week, and cut the remainder over once the new path has a record behind it. Both platforms can authenticate against the same domain during the overlap, so nothing has to be switched on faith.

Will I lose my groups and custom fields?

No. Group membership and custom fields are values carried on the subscriber, and values map across. What doesn't survive is anything that was a view rather than a value: the filter you export through is a screen state and not a column, and engagement categories have no field to arrive in. Write those rules down before you leave, then rebuild them as segments on the other side.

Start with the free tier.

8,000 emails to start, then 500 a month, unlimited contacts, full MCP, API and CLI access. No credit card.