---
title: "Done-For-You Cold Email Infrastructure for Agencies: 7 Providers Compared [2026]"
description: "Which done-for-you cold email infrastructure provider should an agency use? MailDeck, Maildoso, Mailforge, Infraforge, Zapmail, Aerosend and Inframail compared on infrastructure types, published pricing at 1,000 inboxes, cost per 1,000 sends and per-client isolation."
canonical: "https://maildeck.co/blog/done-for-you-cold-email-infrastructure-agencies"
last-updated: "2026-10-03"
---

> Which done-for-you cold email infrastructure provider should an agency use? MailDeck, Maildoso, Mailforge, Infraforge, Zapmail, Aerosend and Inframail compared on infrastructure types, published pricing at 1,000 inboxes, cost per 1,000 sends and per-client isolation.

Comparison

# Done-For-You Cold Email Infrastructure for Agencies: 7 Providers Compared [2026]

Oct 3, 2026 14 min read

Contents

Short Answer: Who Should an Agency Use?What "Done-For-You" Actually CoversThe Seven Providers at a GlanceCost at Agency Scale: 1,000 InboxesThe Honest Version: Cost per 1,000 SendsFour Criteria That Only Matter to AgenciesWhat You Are Still Accountable ForWhen Another Provider Is the Better PickFrequently Asked QuestionsMethodology

## Short Answer: Who Should an Agency Use?

For an agency running cold email for multiple clients, the provider that fits is the one that gives you more than one infrastructure type under one account, isolates each client's domains and inboxes, and prices per unit rather than per seat. On published 2026 pricing, that lands as follows:

- MailDeck — if you need Microsoft Outlook, Google Workspace and private SMTP in one account, per-client separation, and the lowest cost per send. Outlook from $0.30/inbox, Google from $2.99, SMTP from $0.50.

- [Zapmail](https://maildeck.co/alternative/zapmail) — if every client is Google Workspace only and you want nothing else to think about. $2.99–3.50/inbox, the same ballpark as our Google line.

- [Aerosend](https://maildeck.co/alternative/aerosend) or [Infraforge](https://maildeck.co/alternative/infraforge) — if you specifically want aged-IP private SMTP and are willing to pay $3.10–4.00/inbox for it.

- [Maildoso](https://maildeck.co/alternative/maildoso) — Google Workspace plus shared-IP SMTP at $1.90–2.25/inbox, with built-in domain registration and fast onboarding. On Google it is the cheapest per send in this list. On SMTP you share a pool with senders you cannot see, and a dedicated IP is a $99/month add-on.

- [Mailforge](https://maildeck.co/alternative/mailforge) — shared-IP SMTP at $3.00/mailbox. Same pooled-reputation trade as Maildoso’s SMTP, at a higher price.

- [Inframail](https://maildeck.co/alternative/inframail) — only if you are comfortable with pricing that is quoted on a sales call rather than published.

The rest of this page is the working: what "done-for-you" covers at each vendor, what 1,000 inboxes costs across all seven, and the four things that matter to an agency and to nobody else.

## What "Done-For-You" Actually Covers

Every provider in this category uses the phrase. It resolves to six concrete jobs, and vendors differ on which ones they actually do — so the useful question is not whether a vendor is “done-for-you” but which of these six it owns:

| # | The job | What it actually involves | How it fails in practice |
|---|---|---|---|
| 1 | Domain purchase and DNS | Registering sending domains and writing SPF, DKIM, DMARC and MX correctly | The most common and most expensive failure: our audit of 1,000+ client domains found 67% carried at least one critical authentication error before we took them over |
| 2 | Tenant and mailbox provisioning | Creating the Microsoft tenants or Google accounts, the mailboxes inside them and your admin access | Admin access withheld or shared, so you cannot manage or audit what you are paying for |
| 3 | Warmup | A ramp period you wait out, or pre-warmed inventory that sends from day one | Inventory sold as ready that was never warmed — it burns in the first campaign |
| 4 | Sequencer connection | Credentials that drop into Instantly, Smartlead, Saleshandy, Apollo or Lemlist without per-inbox IMAP/SMTP work | Manual setup per inbox, which is invisible at 20 inboxes and a full-time job at 1,000 |
| 5 | Replacement when a domain burns | Issuing a replacement domain, authenticated and warming | Replacement is paid, slow, or undefined — a recurring cost line, not an edge case |
| 6 | Per-client separation | Separate domains and ideally separate tenants per client, so one client's list cannot damage another's | Clients pooled into one sending identity; the job only agencies need, and the one most providers do not do |

Items 1 through 5 are table stakes in 2026 — assume any serious vendor does them. Item 6 is where the agency decision is actually made, and we come back to it below.

## The Seven Providers at a Glance

| Provider | Infrastructure types | Published price per inbox | Pricing public? | Setup included |
|---|---|---|---|---|
| MailDeck | Microsoft Outlook, Google Workspace, private SMTP | $0.30 Outlook / $2.99 Google / $0.50 SMTP | Yes, full ladder | Yes, no setup fee |
| [Maildoso](https://maildeck.co/alternative/maildoso) | Google Workspace, shared-IP SMTP | $1.90–2.25 (dedicated IP +$99/mo) | Yes | Yes |
| [Mailforge](https://maildeck.co/alternative/mailforge) | Shared-IP SMTP | $3.00 | Yes | Yes |
| [Infraforge](https://maildeck.co/alternative/infraforge) | Private SMTP | $4.00 | Yes | Yes |
| [Zapmail](https://maildeck.co/alternative/zapmail) | Google Workspace | $2.99–3.50 | Yes | Yes |
| [Aerosend](https://maildeck.co/alternative/aerosend) | Private SMTP, aged IPs | $3.10–4.00 | Yes | Yes |
| [Inframail](https://maildeck.co/alternative/inframail) | Private SMTP | Quoted on a call | No | Yes |

Six of the seven sell one infrastructure type. That single fact drives most of what follows: a one-type vendor cannot diversify a client's sending risk, and it cannot match infrastructure to audience when one client sells to enterprises on Outlook and the next sells to startups on Gmail.

## Cost at Agency Scale: 1,000 Inboxes Across 20 Clients

Twenty clients at fifty inboxes each is a realistic mid-size agency book. Here is the monthly infrastructure bill at each provider, at published rates:

| Provider and type | Unit price | 1,000 inboxes / month |
|---|---|---|
| MailDeck — Outlook Normal | $30/tenant, 100 inboxes per tenant | $300 |
| MailDeck — Outlook Premium | $40/tenant, 100 inboxes per tenant | $400 |
| MailDeck — private SMTP | $0.50/inbox | $500 |
| Maildoso — Google or shared SMTP | $1.90–2.25/inbox | $1,900–2,250 |
| Mailforge — shared SMTP | $3.00/mailbox | $3,000 |
| MailDeck — Google Workspace | $3.00/inbox at 250–1,249 | $3,000 |
| Zapmail — Google Workspace | $2.99–3.50/inbox | $2,990–3,500 |
| Aerosend — private SMTP | $3.10–4.00/inbox | $3,100–4,000 |
| Infraforge — private SMTP | $4.00/inbox | $4,000 |
| Inframail — private SMTP | Quoted on a call | Not published |

Read that table carefully before you act on it, because cost per inbox is a misleading number on its own. An inbox that safely sends four cold emails a day is not the same unit as one that sends fifteen.

### The honest version: cost per 1,000 sends

Normalising by what each inbox type can safely send per day — 22 working days per month — reorders the table:

| Provider and type | Safe sends / inbox / day | Cost per 1,000 sends |
|---|---|---|
| MailDeck — private SMTP | 10–15 | $1.82 |
| MailDeck — Outlook Premium | 8–10 | $2.02 |
| MailDeck — Outlook Normal | 4–5 | $3.03 |
| MailDeck — Google Workspace | 18–22 | $6.80 |
| Zapmail — Google Workspace | 18–22 | $6.80–7.95 |
| Maildoso — Google Workspace | 18–22 | $4.32–5.11 |
| Maildoso — shared SMTP | 10–15 | $6.91–8.18 |
| Mailforge — shared SMTP | 10–15 | $10.91 |
| Aerosend — private SMTP | 10–15 | $11.27–14.55 |
| Infraforge — private SMTP | 10–15 | $14.55 |

Three things fall out of this. First, Outlook Normal looks cheapest per inbox and is not cheapest per send — it is the cheapest way to buy breadth across many domains, not the cheapest way to buy volume. Second, on Google Workspace, Zapmail and MailDeck cost effectively the same. If Google is all you need, there is no price argument between us; the argument is whether you will later want Outlook or SMTP in the same account. Third, Maildoso is cheaper than either of us on Google Workspace — $4.32–5.11 per 1,000 sends against our $6.80 — so if Google-only at the lowest price is the whole requirement, that is the honest answer.

The per-day figures are the limits we enforce across our own platform. Where a competitor publishes its own limits and they differ, use theirs — see Methodology.

## Four Criteria That Only Matter to Agencies

A single-brand sender and a twenty-client agency are not buying the same product. These four are the ones that separate them.

### 1. Client isolation

One client's bad list must not damage another client's deliverability. That means separate domains per client, and ideally separate tenants, so that a spam complaint spike is contained. If a provider pools your clients into one sending identity, a single bad campaign becomes everyone's problem — and you will be explaining it to clients who did nothing wrong. We cover the architecture in detail in [how to manage 500+ inboxes without burning domains](https://maildeck.co/blog/cold-email-agency-inbox-management). On MailDeck, Outlook inboxes sit on individual US Microsoft tenants, and workspaces and team members are unlimited, so one workspace per client costs nothing extra.

### 2. Provider diversification

If every client sits on one infrastructure type and that type has a bad month, your whole book has a bad month at the same time. This is the single largest concentration risk an agency carries, and it is invisible until it fires. Our [diversification guide](https://maildeck.co/blog/cold-email-infrastructure-diversification) sets out the ratio we recommend — roughly 50% Outlook, 30% SMTP, 20% Google — which is also how the Diversified Stack bundles are built ($99/mo for 40,000 sends, $399 for 215,000, $3,499 for 2.15M). Six of the seven providers here cannot offer this at all, because they sell one type.

### 3. Volume breaks on cumulative, not per-order, units

Agencies add clients one at a time. If the rate ladder resets with every order, you never reach the discounted tier. MailDeck sets the rate by your cumulative units on a product: an account already at 15 Outlook Normal tenants that adds 10 more bills the whole new order at the 21+ rate ($28/tenant), not the entry rate. Outlook Normal steps $30 → $28 → $25; Premium $40 → $38 → $35; SMTP $0.50 → $0.45 → $0.40; Google $3.50 → $3.00 → $2.80. Full ladder on the [pricing page](https://maildeck.co/pricing).

### 4. Free domain replacement

At 100K+ sends per month, 10–20% of domains burn monthly and a domain's working life under load is roughly 45 days to two months. Whether replacement is included or billed decides whether your margin survives month six. Free domain replacement is included on every MailDeck Outlook and pre-warmed tier. Check this line explicitly with any vendor you shortlist — it is rarely on the pricing page.

## What You Are Still Accountable For on Every Client Domain

“Done-for-you” never means done. Whatever a provider provisions, the receiving side holds the sending domain responsible, and at an agency that domain is your client's. The requirements below are published by the receivers themselves, so they are the same for all seven providers — what differs is only who does the work.

| Requirement | Published by | Who usually owns it | How you verify it per client |
|---|---|---|---|
| SPF and DKIM on every sending domain | Google's [email sender guidelines](https://support.google.com/a/answer/81126); [RFC 7208](https://datatracker.ietf.org/doc/html/rfc7208) and [RFC 6376](https://datatracker.ietf.org/doc/html/rfc6376) | Provider provisions, you confirm | [MXToolbox](https://mxtoolbox.com/) lookup per domain at handover |
| A DMARC record, aligned with the sending domain | Google's sender guidelines; [RFC 7489](https://datatracker.ietf.org/doc/html/rfc7489) | Frequently nobody — this is the most common gap | DMARC lookup per domain, before the first send |
| Spam complaint rate kept below 0.3% | Google's sender guidelines | You — it is a function of list and copy | [Postmaster Tools](https://postmaster.google.com/), per client domain |
| Sending IP reputation | Microsoft, via [SNDS](https://sendersupport.olc.protection.outlook.com/snds/) | Provider, if the pools are theirs | SNDS for Outlook traffic; ask which pools a client sits on |
| Per-inbox daily send rate | Nobody — platform limits are far above safe cold rates | You, in the sequencer | Daily volume divided by inbox count, per client |

Two of those rows are the ones that bite agencies specifically. The first is DMARC: it falls between the provider, who provisioned the domain, and the client, who owns the brand, and so it is often simply absent — 19% of the domains we have audited had no DMARC record at all, and 67% of the 1,000+ total carried at least one critical authentication error. The second is the complaint rate, because it is the one number no provider can fix for you. If a client's list is bad, every provider on the list above produces the same outcome.

The operational answer is a handover check you run once per client domain rather than once per provider: authentication lookup, DMARC present, pools named, daily rate set in the sequencer. Our [30-minute infrastructure audit](https://maildeck.co/blog/cold-email-infrastructure-audit) is that sweep written out, and at 20 clients it is the difference between finding a missing record at handover and finding it in a deliverability post-mortem three months later.

## When Another Provider Is the Better Pick

Three honest cases:

- You want pre-warmed Google Workspace or pre-warmed SMTP inboxes. Both are sold out on MailDeck at the time of writing. Our pre-warmed Outlook tenants are available at $40/tenant for 100 inboxes; the other two have a notify form and nothing else. If pre-warmed Google is a hard requirement this month, buy it elsewhere.

- Every client is Google Workspace and always will be. Zapmail is priced at parity with our Google line and does one thing. There is no cost case for switching, only a flexibility case.

- You have a specific reason to want aged third-party IPs. Aerosend and Infraforge sell exactly that. We route Outlook and Google through official Microsoft and Google IP pools instead, which is a different bet about where reputation comes from — see [shared IP vs dedicated IP](https://maildeck.co/blog/shared-ip-vs-dedicated-ip-cold-email).

And one case where the honest answer is "not yet": private SMTP has a 100-inbox minimum order, so it belongs in the mix once you are scaling, not in a first client's setup.

## Frequently Asked Questions

### What is done-for-you cold email infrastructure?

Done-for-you cold email infrastructure means a provider buys and configures the sending assets for you: domains with correct SPF, DKIM, DMARC and MX records, mailboxes on Microsoft 365, Google Workspace or private SMTP, warmup, and credentials that connect directly to your sequencer. You supply the copy, the list and the sequencer; the provider supplies inboxes that land. It does not include the sequencer itself — MailDeck is not a sequencer, and every plan connects to any SMTP-compatible sending tool including Instantly, Smartlead, Saleshandy, Apollo and Lemlist.

### Which cold email infrastructure provider is best for an agency?

For an agency the deciding factors are per-client isolation, more than one infrastructure type in one account, and volume breaks that accumulate across clients rather than resetting per order. MailDeck covers Microsoft Outlook, Google Workspace and private SMTP from $0.30/inbox with unlimited workspaces and team members, which is why it suits multi-client books. If every client is Google Workspace only, Zapmail is priced at parity and is simpler. If you want aged-IP private SMTP specifically, Aerosend and Infraforge sell that at $3.10–4.00 per inbox.

### How much does cold email infrastructure cost for an agency with 20 clients?

At 1,000 inboxes across 20 clients, published 2026 rates run from $300/month (MailDeck Outlook Normal, 10 tenants at $30) to $4,000/month (Infraforge private SMTP at $4.00/inbox). Google Workspace sits around $3,000/month at both MailDeck and Zapmail. Cost per inbox is misleading on its own, because inbox types differ in how much they can safely send: normalised to cost per 1,000 sends, the range is $1.82 (MailDeck private SMTP) to $14.55 (Infraforge).

### Can one account keep each client's cold email infrastructure separate?

Yes, and it is the thing to insist on. Each client needs its own sending domains, and preferably its own tenants, so one client's spam complaints cannot damage another's deliverability. On MailDeck, Outlook inboxes are provisioned on individual US Microsoft tenants and workspaces and team members are unlimited, so one workspace per client adds no cost. Providers that pool clients into a shared sending identity turn one bad campaign into every client's problem.

### Do cold email providers replace burned domains for free?

Some do, some bill for it, and it is rarely stated on the pricing page — ask before signing. It matters more than most agencies expect: at 100,000+ sends per month, 10–20% of domains burn monthly and a sending domain's working life under load is around 45 days to two months. Free domain replacement is included on every MailDeck Outlook and pre-warmed tier. Keep 20–25% of your active domain count as warmed reserves regardless, because replacement without reserves costs 7–10 days including warmup.

### Should an agency use one infrastructure provider or several?

Use several infrastructure types, ideally through one account. Concentrating an entire client book on a single provider type means that when that type has a bad month, every client has a bad month simultaneously. The ratio we recommend is roughly 50% Microsoft Outlook, 30% private SMTP and 20% Google Workspace. The practical compromise is one vendor that sells all three, which keeps billing and support in one place while spreading the delivery risk.

### Is Microsoft Outlook or Google Workspace better for agency cold email?

Google Workspace lands best and costs the most per inbox, at roughly $2.99 and 18–22 safe cold sends per inbox per day. Microsoft Outlook is where the volume economics are, at roughly $0.30–0.40 per inbox with 4–5 sends on the Normal licence or 8–10 on Premium, and 100 inboxes per tenant. Most agency books should not sit entirely on either. See our [Microsoft 365 vs Google Workspace benchmark](https://maildeck.co/blog/microsoft-365-vs-google-workspace-cold-email) for the deliverability data behind this.

### What does an agency still have to do when infrastructure is done-for-you?

Four things no provider does for you. Confirm SPF, DKIM and DMARC on every client domain at handover, because DMARC in particular falls between the provider and the client and is often simply missing: 19% of the domains we have audited had no DMARC record. Keep each client's spam complaint rate below the 0.3% threshold in Google's email sender guidelines, which is a function of list and copy rather than infrastructure. Set the per-inbox daily send rate in the sequencer, since platform limits sit far above safe cold rates. And know which IP pools each client sends from, so that when placement drops you can tell a provider problem from a list problem. Everything else is genuinely provisionable.

### How do I keep 20 clients' cold email domains authenticated?

Run the same check once per client domain rather than once per provider, at handover and after any domain change: exactly one SPF record resolving within the 10-lookup limit, DKIM signing and resolving, a DMARC record aligned with the sending domain, and the IP pools named. MXToolbox covers the DNS side in a minute per domain, Google Postmaster Tools reports per-domain reputation and spam rate for Gmail traffic, and Microsoft SNDS covers IP reputation for Outlook traffic. At agency scale the value is in doing it as a gate before the first send: 67% of the 1,000+ cold email domains we have audited carried at least one critical authentication error, and almost all of them were cheap to fix before volume started and expensive afterwards.

## Methodology

MailDeck figures come from our published [pricing page](https://maildeck.co/pricing) and from platform data: 833K+ managed inboxes, 3,000+ domains, 1,631+ clients, 50M+ emails delivered monthly. Safe sends per inbox per day are the limits we enforce across our own platform, and the DNS error rate comes from a scan of 1,000+ client domains.

Unverified: competitor prices are taken from our own [alternatives pages](https://maildeck.co/alternative), which were last checked against each vendor's public pricing in May 2026, and were not re-checked on the vendors' sites on the publication date of this article. Inframail does not publish pricing at all. Cost per 1,000 sends for competitors applies our safe-send limits for the matching infrastructure type, because most of these vendors do not publish per-inbox daily limits; where a vendor publishes its own figure, use theirs. Treat the per-send column as a like-for-like comparison of infrastructure types, not as a vendor claim.

Last updated: October 2026

Written by [Nikita Stoletov](https://maildeck.co/authors/nikita-stoletov)

CTO | Outbound Infrastructure & Deliverability Engineering

Built the infrastructure delivering 50M+ emails monthly across 3,000+ domains with 98% inbox placement at MailDeck.

[LinkedIn](https://www.linkedin.com/in/nikita-stoletov-30b817292)

[View Profile](https://maildeck.co/authors/nikita-stoletov)

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## Continue Reading

[Guide](https://maildeck.co/blog/cold-email-agency-inbox-management)

### [Cold Email for Agencies: How to Manage 500+ Inboxes at Scale](https://maildeck.co/blog/cold-email-agency-inbox-management)

[Client isolation architecture, domain structure per client and the agency cost math behind running 30-40 clients on one stack.](https://maildeck.co/blog/cold-email-agency-inbox-management)

[Guide](https://maildeck.co/blog/cold-email-infrastructure-diversification)

### [Cold Email Infrastructure Diversification: Why One Provider Isn't Enough](https://maildeck.co/blog/cold-email-infrastructure-diversification)

[Why concentrating a whole book on one infrastructure type is the largest risk an agency carries, and the ratio that spreads it.](https://maildeck.co/blog/cold-email-infrastructure-diversification)

[Guide](https://maildeck.co/blog/how-to-start-cold-email-agency)

### [How to Start a Cold Email Agency in 2026](https://maildeck.co/blog/how-to-start-cold-email-agency)

[Startup costs, tool stack, pricing models and profit margin benchmarks from month one to twenty clients.](https://maildeck.co/blog/how-to-start-cold-email-agency)