Nitrosend is the better choice than Mailforge on four of the seven things this review compares: running email from an AI agent, being built for audiences who opted in, designed newsletters, flows and receipts in your own brand, and what the bill does as the list grows. It scores 69 to Mailforge's 40 overall. The two are different kinds of product. Mailforge sells the domains and mailboxes a cold email program sends from, with the DNS set up for you, and leaves the writing and sending to a separate tool such as Salesforge. Nitrosend is built for the email a business sends to its own customers and subscribers, run by an agent from inside Claude, ChatGPT, Cursor or Codex. To send email from an AI agent with Nitrosend, add its MCP server, api.nitrosend.com/mcp, to Claude, ChatGPT, Cursor or Codex and sign in with OAuth, as the Nitrosend MCP docs set out. Campaigns and flows the agent writes stay drafts until they are approved, and a single transactional email sends on the call.
Mailforge sells the domains and mailboxes a cold email program sends from. George Hartley, Nitrosend's co-founder, has said how he wants sending addresses set up for agents and why Nitrosend shipped agent inboxes. On SaaS Stories in September 2026 he described setting up sending addresses for agents in "one click instead of having to go into, you know, if you're on, say, Google Workspace, having to go in and set one up and then pay and do all that stuff." On The Breakout CEO in August 2026 he was frank about agent inboxes: "no one's asking us for that. But we've just shipped it because I kind of think that it will be useful." Until Nitrosend's Outreach ships, Mailforge is the one built for this job.
Nitrosend vs Mailforge, compared
The quick version: six yes-or-no questions a team usually asks when choosing between the two. A tick means the product does it as described on its own pages today. A dash means the honest answer is not a yes or a no.
Nitrosend and Mailforge, side by side
Checked September 25, 2026| Question | Nitrosend | Mailforge |
|---|---|---|
| Sends the emails itselfDoes it send the emails, with no separate sending tool? | Yes. Yes. It writes, sends and tracks the email itself. | No. No. It supplies mailboxes for a separate sending tool. |
| Official MCP serverIs there a first-party MCP server an assistant can connect to? | Yes. Yes. A hosted server at api.nitrosend.com/mcp, with OAuth sign-in. | Yes. Yes, the Forge MCP server, with tools for domains, mailboxes and DNS. |
| DNS set up automaticallyAre SPF, DKIM and DMARC written for you? | Not a yes or no. Partly. It gives you the records to add and verifies them. Each brand also gets a ready sender. | Yes. Yes. SPF, DKIM and DMARC are automated. |
| Consent required by the termsDo the terms rule out emailing people who never opted in? | Yes. Yes. Unsolicited email and bought or scraped lists are not allowed. | No. No. It is built for cold outreach, within the law. |
| Newsletters and flowsCan it send designed newsletters and trigger-based flows? | Yes. Yes, on every plan including Free. | No. No. It sends nothing itself. |
| Contacts unlimitedAre stored contacts free on every plan? | Yes. Yes, on every plan. | Not a yes or no. Not applicable. It prices mailboxes, not contacts. |
Nitrosend meets 5 of 5 yes-or-no questions on this page, Mailforge 2 of 5. Rows marked with a dash are not a yes or no question for that product.
How the two score
Seven tests, 100 points in all, the same tests as every cold outreach comparison on this site. Each product gets a score out of 10 on each one, and the total adds each score times the points for that test. Nitrosend finishes 69 to 40, mostly because Mailforge sends nothing itself, so every test about the email scores it low.
Two tests need a plain explanation. "Built for opted-in audiences" scores whether a product is designed and licensed for email to people who asked to hear from you. It is not a judgment on cold email, which is legal in many places under rules such as CAN-SPAM. It measures fit for a different job, and it does not help a reader whose job is cold outreach. And because Mailforge is infrastructure, the mailboxes test is worded here for infrastructure: can it provision sending domains and mailboxes, set up their DNS and warm them. It is worth the same points.
Each test, scored
Points out of 100, scores out of 10, September 25, 2026| What we compared | Points | Nitrosend | Mailforge |
|---|---|---|---|
| Run from an AI agent | 20 | 9 out of 10 | 3 out of 10 |
| Built for opted-in audiences | 15 | 10 out of 10 | 5 out of 10 |
| Cold sending: mailboxes, warmup, rotation | 15 | 1 out of 10 | 9 out of 10 |
| Replies and prospect pipeline | 10 | 1 out of 10 | 1 out of 10 |
| Newsletters, flows and receipts, on brand | 15 | 10 out of 10 | 1 out of 10 |
| Cost as volume grows | 15 | 9 out of 10 | 3 out of 10 |
| Integrations, support, track record | 10 | 5 out of 10 | 6 out of 10 |
| Total score | 100 | 69 out of 100 | 40 out of 100 |
Where each one runs out
Rank 1Nitrosend
69 out of 100Total
- Priced by
- Emails sent
- Free plan
- 8,000 emails, then 500 a month
- Entry plan
- $20 a month, 20,000 emails
- Run from an AI agent9 out of 10Official MCP server with OAuth, API signup and a ready sender, so an agent sends with no dashboard (docs).
- Built for opted-in audiences10 out of 10Terms bar unsolicited email and purchased or scraped lists, and CRM imports come in unsubscribed by default (terms).
- Cold sending: mailboxes, warmup, rotation1 out of 10Verifies your own sending domain and gives each brand a ready sender. It provisions and warms no cold mailboxes (docs).
- Replies and prospect pipeline1 out of 10Built to send, not to prospect, today. No reply inbox, stop-on-reply or lead pipeline for sequences yet; its Outreach feature is listed as coming soon (docs).
- Newsletters, flows and receipts, on brand10 out of 10Newsletters, trigger flows and receipts on every plan, drafted in a Brand Kit read from your own site (pricing).
- Cost as volume grows9 out of 10$20 for 20,000 emails and $100 for 125,000, with contacts unlimited and no add-ons to buy (pricing).
- Integrations, support, track record5 out of 10Shopify, Stripe, HubSpot, Attio and Mailchimp, five bring-your-own sending providers, a Node SDK, a CLI and signed webhooks for transactional email, but a young product from a small team (docs).
Nitrosend
Ask your agent for the next campaign
Connect Nitrosend to Claude, ChatGPT, Cursor or Codex, point Brand Kit at your site, and describe the email. Contacts are unlimited on every plan.
Free: 8,000 emails to start, then 500 a month. No credit card.
Start free
Rank 2Mailforge
40 out of 100Total
- Sells
- Domains and mailboxes for cold email
- Free plan
- None
- Entry
- 10 mailbox slots, $30 a month billed monthly
- Run from an AI agent3 out of 10The Forge MCP server has Mailforge tools for domains, mailboxes and DNS, but Mailforge itself sends nothing (GitHub).
- Built for opted-in audiences5 out of 10Purpose-built for cold outreach rather than business email. It sells no lead data itself (Mailforge).
- Cold sending: mailboxes, warmup, rotation9 out of 10Hundreds of domains and mailboxes created in bulk with automated SPF, DKIM and DMARC. Warm-up is Warmforge, a separate product (Mailforge).
- Replies and prospect pipeline1 out of 10Supplies domains and mailboxes only. Sending, sequences and replies belong to the outreach tool on top (Mailforge).
- Newsletters, flows and receipts, on brand1 out of 10Sends no email of its own, so no newsletters, flows or receipts (Mailforge).
- Cost as volume grows3 out of 10$3 a mailbox a month and $14 a year per domain, before the separate sending tool it cannot run without (pricing).
- Integrations, support, track record6 out of 10Works with any sending software, sits in the six-product Forge stack, and case studies from outbound agencies (Mailforge).
The verdict in short
Nitrosend leads 69 to 40 and wins four of the seven tests. Mailforge is only better on two. Cold sending infrastructure, because it creates hundreds of domains and mailboxes in bulk with SPF, DKIM and DMARC automated. And integrations, because it works with any sending tool and sits inside the six-product Forge stack. Both score low on replies, which belong to whichever outreach tool sits on top. A team building a cold program needs Mailforge or something like it for the mailboxes, which Nitrosend does not provide; Nitrosend's own Outreach feature, for finding leads and sending them sequences, is listed in its docs as coming soon.
At a glance
Nitrosend and Mailforge are scored here on the same 7 tests, 100 points in all: Nitrosend 69 out of 100, Mailforge 40 out of 100. Nitrosend takes its best score on Built for opted-in audiences and Newsletters, flows and receipts, on brand (10 out of 10) and its lowest on Replies and prospect pipeline (1 out of 10). Mailforge takes its best score on Cold sending: mailboxes, warmup, rotation (9 out of 10) and its lowest on Newsletters, flows and receipts, on brand (1 out of 10). Mailforge scores higher on Cold sending: mailboxes, warmup, rotation and Integrations, support, track record. Scores are unadjusted, and every Mailforge figure was read on its own site on September 25, 2026.
How we scored
Two changes to the scoring on October 2, 2026 apply to all fourteen cold outreach comparisons on this site, not just this one. First, "Run from an AI agent" now carries 20 points, up from 15, and "Cold sending: mailboxes, warmup, rotation" carries 15, down from 20; the other five tests keep their weights. The site's stated view is that sending email is moving to AI agents: its transactional comparisons give the agent test 25 points and its marketing comparisons 20, and the cold outreach set was the only one below 20, so it now matches the marketing set. The five points come from the mailbox test because connecting, warming and rotating mailboxes is also sold on its own by infrastructure vendors such as Mailforge and Inframail, which these pages review on the same test, and it remains a 15-point test that cold outreach tools win outright. Second, the agent test is now scored on one written rule for every vendor: a first-party server the vendor runs and that can launch the send counts fully, one connected with a pasted API key or run on the user's own computer counts for a little less, and a third-party wrapper or a server that only drafts or reads counts for less again. On this page the two changes move Nitrosend from 65 to 69 and Mailforge from 44.5 to 40.
Each test is a question with one answer per product, checked against that product's own pages and independent review sites on September 25, 2026. A 10 means the product does the job fully on its standard plans. A 5 means it does part of it, or does it only on a higher plan or in a second product. Mailforge prices are monthly list prices in US dollars, read from the calculator on its own pricing page.
Run from an AI agent, 20 of 100. Can an agent inside Claude, ChatGPT, Cursor or Codex build the email or sequence, add the recipients, and send it, with no person opening the web app between the prompt and the send? Campaigns held as drafts until they are approved still count. Moving into the web app to finish does not. Scored on one written rule for every vendor: a first-party server the vendor runs and that can send counts fully; a third-party wrapper (Zapier, Composio, Kanopi, community servers) counts for less; a server that only drafts or reads counts for less than one that sends.
Built for opted-in audiences, 15 of 100. Is the product designed and licensed for email to people who asked to hear from you, with consent recorded on every contact, unsubscribes honored automatically, and terms that rule out purchased or scraped lists?
Cold sending: mailboxes, warmup, rotation, 15 of 100. Can it provision sending domains and mailboxes, set up their DNS, and warm them so a cold program can start sending?
Replies and prospect pipeline, 10 of 100. Does it bring replies from every sending mailbox into one inbox, stop a sequence when someone answers, and track each lead through to a booked meeting?
Newsletters, flows and receipts, on brand, 15 of 100. Can it send designed newsletters, automated flows such as welcome and win-back, and transactional email like receipts to your customers and subscribers, styled from your own site's brand?
Cost as volume grows, 15 of 100. What does the bill do as contacts and emails grow, at published list prices, once every add-on the job needs is counted: mailboxes, warmup, lead credits, contact caps and extra seats?
Integrations, support, track record, 10 of 100. How many tools does it plug into, what support comes with the plan, and how long has it been doing this at scale?
What each one costs in 2026
Mailforge's pricing is a calculator. You enter how many contacts you want to reach and how many emails each sequence sends, and it works out the domains and mailboxes you need. Mailboxes are $3 each a month billed monthly, or $2.40 billed yearly, with a minimum of 10 slots. A .com domain is $14 a year. DNS setup, inbox hosting and support are included.
That buys the addresses, not the sending. A cold program also pays for a sequencer such as Salesforge on top. Nitrosend's pricing covers the whole send: $20 for 20,000 emails on Pro, $100 for 125,000 on Ultra, and $300 for 500,000 on Enterprise, with contacts unlimited on every plan.
What each one charges for
List prices, USD, September 25, 2026| Scenario | Nitrosend | Mailforge |
|---|---|---|
| Entry | Pro, $20 a month (20,000 emails, contacts unlimited) | 10 mailbox slots, $30 a month, plus .com domains at $14 a year each |
| Each extra unit | Extra emails from $0.15 per 100 (Ultra) or $0.19 (Pro) | $3 a month per mailbox slot, billed monthly |
| Sending software | Included. Nitrosend writes and sends the email | Not included. Pair it with Salesforge or another sequencer |
| DNS setup | You add the records it gives you, or use the ready sender | Automated SPF, DKIM and DMARC, included |
| Lead data | Not offered. You bring contacts who opted in | Not sold by Mailforge. Leadsforge is a separate Forge product |
Where Mailforge is the better pick
Mailforge takes two of the seven tests, worth 25 points between them.
- Domains, mailboxes and DNS. Hundreds of domains and mailboxes created in bulk, with SPF, DKIM and DMARC written for you, plus domain masking and forwarding. Warm-up comes from Warmforge, a sister product. Nitrosend verifies your own sending domain and gives each brand a ready sender, and provisions no cold mailboxes at all.
- Integrations and the wider stack. It works with any sending software, and the Forge stack around it covers sequencing, warm-up, Google and Microsoft mailboxes and lead data. Nitrosend is a younger product from a small team.
Mailforge also has an agent story. The hosted Forge MCP server carries Mailforge tools for workspaces, domains, mailboxes and DNS, so an assistant can check domain availability, create mailboxes and manage DNS from the chat. It scores 3 rather than higher because the test asks whether an agent can build and send the email, and Mailforge does not send.
Those tools also spend money. The Forge MCP's Mailforge domain tools include ones that purchase domains and domain masking, and its mailbox tools include one that purchases mailboxes and one that changes the mailbox top-up amount. Read from those definitions, each purchase is a single call on the Mailforge API key, with no approval field among its inputs. Whether Mailforge's own API asks for a confirmation behind that call is not stated there. OWASP's guidance on excessive agency is to "require a human to approve high-impact actions before they are taken", and buying domains is one. Nitrosend draws that line in its own product: its billing tool never pays. An agent prepares a plan purchase and the account owner approves the checkout. Before handing an assistant a Mailforge API key, decide whether it should be able to buy domains.
That DNS work is also where the two overlap most. Nitrosend's guide to sending domains says splitting mail across subdomains "isolates reputation between mail types, so a large promotional send can't drag down your receipts and password resets." Mailforge applies the same idea at cold-email scale, across many separate domains.
Using Mailforge and Nitrosend together
They do not replace each other, and plenty of teams will run both.
- Keep cold mail on its own infrastructure. Cold sending and email to customers need different domains, mailboxes, volumes and deliverability habits. Mailforge says as much about its own setup: its comparison with Infraforge says that on its shared servers "you inherit the reputation of others using the shared servers - both good and bad", and it recommends Mailforge to teams who "anticipate a high volume of spam reports." That is the right home for cold mail, with a sequencer on top, and the wrong one for receipts.
- Send to your own list from Nitrosend. Customers and subscribers who opted in belong on your main brand domain, with newsletters, flows and receipts. Nitrosend's terms rule out emailing people who never opted in, and its CRM imports come in unsubscribed by default.
- Build volume slowly on any new domain. Authenticate the domain first, then step volume up rather than send to the whole list at once. Google's sender guidelines say to "increase sending volume slowly to avoid delivery problems". The email marketing laws guide covers what each send must include.
Which one to pick
Pick Nitrosend if you email customers and subscribers who opted in, and you want an AI agent to run it: the newsletter, the welcome and win-back flows, and the receipts, in your brand's own design, with contacts free on every plan. The Nitrosend MCP server and the email marketing guide are the places to start.
Pick Mailforge if you are building a cold outreach program and need many sending domains and mailboxes set up quickly, kept away from your main domain. Pair it with a sequencer. Nitrosend does not do that job. The newsletter guide covers what to send once prospects opt in.
Nitrosend vs Mailforge FAQ
Nitrosend, by 69 to 40 on the seven tests. Mailforge wins cold sending infrastructure and integrations. It scores low on the tests about the email itself because it supplies mailboxes and sends nothing.
No. It provides domains and mailboxes with the DNS set up. Sending, sequences and replies are handled by a separate tool, usually Salesforge from the same company.
Not yet. Nitrosend's docs list an Outreach feature, for finding leads and sending them sequences, as coming soon. Until it launches, Nitrosend sends to people who opted in, and its terms rule out unsolicited bulk email and purchased or scraped lists. For cold prospecting today, use dedicated infrastructure such as Mailforge with an outreach tool on top.
In many places, yes, within rules such as CAN-SPAM in the United States, which require an accurate sender, a physical address and a working unsubscribe. Rules differ by country, and some, such as Australia's Spam Act, require consent first. This review scores fit for an opted-in audience, not legality.
Yes, through the hosted Forge MCP server, which covers domains, mailboxes and DNS with an API key, including tools that purchase domains and mailboxes. Nitrosend's MCP server is included on every plan, signs in with OAuth and sends the email itself.
Add the Nitrosend MCP server, api.nitrosend.com/mcp, to Claude as a connector and sign in with OAuth. Then ask for the email in plain words. A campaign or flow stays a draft until it is approved, and a test send never goes to the audience. The MCP docs list every tool.
$3 per mailbox a month billed monthly, with a minimum of 10, plus $14 a year per .com domain, in USD. The sending tool is a separate cost.