Head to head

Instantly vs Warmbox

Same facts, side by side: starting price, free tier, MCP, API and what each one is actually built for.

Instantly

$47/mo Free trial

Cold-email infra for teams farming many sending mailboxes. Public Outreach start is $47/mo monthly.

Where Instantly fits

Outbound recruiting teams sending at volume
Agencies running many sending accounts
Desks that need warmup plus a unibox
MCP/API automation around campaigns

Warmbox

$15/mo

Warmbox runs automated email warmup to lift sender reputation. The listing floor is $15/mo.

Where Warmbox fits

New domains that need a warmup network before cold volume
Solo senders who want a dedicated warmup tool under $20/mo
Agencies warming many client inboxes on a low per-box bill
Teams that already sequence in Instantly and want a second warmup opinion

At a glance

Detail	Instantly	Warmbox
Starting price	$47/mo	$15/mo
Free tier	–No	–No
Free trial	Yes	Not on record
MCP server	✓Yes	–No
Public API	✓Yes	–No
Listed under	Lead generation, Outreach	Deliverability

Where they pull apart

Instantly

Stands out: Warmup, unibox, and volume send with hosted MCP and a public API.

Watch out: Deliverability still depends on your domains and inboxes, not the tool alone.

Not the right fit for

Teams that only need LinkedIn messaging
Buyers looking for an ATS

Warmbox

Stands out: $15/mo is the cheapest dedicated warmup listing in this set, below Mailreach's $20/mo and well below Folderly's $79/mo monitor.

Watch out: Warmup is not sending. You still need a sequencer. Results take weeks, and a burned domain will not be saved by a $15 plan alone.

Not the right fit for

Buyers who want inbox-placement analytics, not a warmup bot
Teams that expect warmup to replace authentication and list hygiene

Pros and cons

Instantly

Warmup and unibox in the same desk
Hosted MCP plus REST API
No-card get-started path on the vendor site

Sending domains and inboxes are bought separately
Sequence designer is plainer than multichannel rivals
Volume tiers step up quickly as mailboxes grow

Warmbox

Published $15/mo listing, low for a dedicated warmup network
Unbundled from any one sequencer
Simple job: reputation, not campaigns

Does not send campaigns or host mailboxes
Overlap with Instantly and Smartlead bundled warmup
Will not rescue a domain with a broken DMARC record

What each one costs

Instantly

$47/mo

From ~$30/mo. Confirm current terms on the vendor site.

Checked 17 Sep 2026

Warmbox

$15/mo

Warmbox lists from $15/mo for automated email warmup. Confirm live per-mailbox versus flat pricing and any volume packs on the vendor pricing page. Confirm current terms on the vendor site.

Checked 19 Sep 2026

Common questions

Is Instantly cheaper than Warmbox?

Warmbox starts lower, at $15/mo against $47/mo for Instantly. That is the entry plan on each side, so the real number depends on seats and the tier you land on.

Can you try Instantly or Warmbox for free?

Neither carries a free tier on our listing. Instantly offers a free trial.

Does Instantly or Warmbox have an MCP server?

Instantly ships a first party MCP server, so an AI assistant can work the product directly.

Not the pair you wanted?

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Editorial listings, never paid rankings. Prices checked 17 Sep 2026. Confirm current terms on the vendor site. Spot an error?