A cold email warm-up tool sends and replies to mail between your new mailbox and a network of other inboxes, so Gmail and Outlook see steady, wanted traffic before you start prospecting. Anyone who sends cold email from a fresh domain needs one, and so does anyone adding mailboxes in bulk.
Teams switch warm-up tools for three reasons. Per-mailbox pricing climbs fast past 20 inboxes. Daily warm-up caps are low on cheap tiers. And warm-up fixes nothing when the list is bad.
That last point is where most guides stop. We have not run an inbox-placement test on these tools, so this page ranks them on published limits and price, not on invented results. Read the schedule side in how long to warm up email and the scripted version in automated email warm-up.
TL;DR
| Tool | Best for | Starting price | Cost at 1M records a month |
|---|---|---|---|
| Instantly | Agencies with many mailboxes | $47 a month (Growth, monthly) | Not applicable: priced by emails sent, not records |
| Smartlead | Private warm-up pool and unlimited mailboxes | $39 a month (Base), $32.50 billed yearly | Not applicable: priced by emails sent |
| lemlist | Warm-up inside a multichannel sequencer | $69 a month, $55 billed yearly | Not applicable: warm-up is bundled |
| MailReach | Careful, per-mailbox reputation tracking | $25 per mailbox a month | Not applicable: priced per mailbox |
| Warmy | Teams that want a dedicated expert | $49 a month | Not applicable: volume-based warm-up pricing |
| Warmup Inbox | Cheapest per-mailbox start | $15 per inbox a month (list price, monthly view) | Not applicable: priced per inbox |
| LeadOcean | The verified list behind the warm-up | Free, then $97 a month (Solo) | $497 a month (Agency), no per-record price |
What we evaluated
- Price per mailbox. What one warmed inbox costs at 1, 10 and 50 mailboxes.
- Daily warm-up cap. How many warm-up messages a mailbox can send each day.
- Pool and method. Private or public network, and how replies and opens are simulated.
- API and MCP access. Whether you can script warm-up status or hand it to an agent.
- What it cannot do. No tool here fixes a stale or unverified list.
1. Instantly: best for agencies with many mailboxes
Instantly includes unlimited email accounts and unlimited warm-up on every outreach plan. Growth is $47 a month and Hypergrowth is $97 a month, both on the monthly view (instantly.ai/pricing, October 2026).
Warm-up is a one-click switch. The ramp starts at 2 emails on day 1 and adds 2 a day. Instantly says the network holds over 1,000,000 real accounts and uses headless browsers for read emulation (instantly.ai/email-warmup, October 2026).
The catch is that you pay for the sequencer to get the warm-up. Growth caps uploaded contacts at 1,000 and sends at 5,000 a month. Instantly publishes API v2 docs and an MCP connection (developer.instantly.ai, October 2026).
Pros
- Unlimited mailboxes and unlimited warm-up on every outreach plan.
- Slow ramp you can reason about: 2 emails more each day.
- API v2, webhooks, SDK and an MCP connection.
- Pool of over 1,000,000 accounts, per Instantly.
Cons
- Warm-up is bundled with a sequencer you may not want.
- Growth caps sends at 5,000 a month.
- Pool size is a vendor claim, not an audited number.
Best for: agencies running dozens of mailboxes who also want the sequencer. Pricing: Growth $47 a month, Hypergrowth $97 a month, Light Speed $358 a month (source, October 2026).
2. Smartlead: best for a private warm-up pool
Smartlead runs a curated warm-up pool and says only vetted senders get in. Bounce spikes or spam flags pause a mailbox automatically, and it resumes after a cool-down (smartlead.ai/email-warmup, October 2026).
Its plans scale by sends, not mailboxes. Base lists 6,000 sends a month, Pro 90,000, Smart 150,000 and Prime 500,000 (smartlead.ai/pricing, October 2026). It also sells mailboxes at $4.50 a month each, and pre-warmed mailboxes at $9 (Smartlead pricing, October 2026). The warm-up pool tier rises with the plan: Foundation on Base, Growth on Pro, Premium on Smart and Prime.
API and webhooks start on Pro. We found no MCP server on the pricing or warm-up pages in October 2026.
Pros
- Private pool with auto-pause on bounce spikes.
- Unlimited mailboxes on warm-up, per the page.
- Pre-warmed mailboxes available if you would rather buy than wait.
Cons
- No API on Base.
- No MCP server listed.
- Warm-up pool size is not published.
Best for: teams that care about a clean pool and plan to send 90,000 or more emails a month. Pricing: Base $39, Pro $94, Smart $174, Prime $379 a month; $32.50, $78.30, $144.50 and $314.60 billed yearly (source, October 2026).
3. lemlist: best for warm-up inside a multichannel tool
lemlist bundles warm-up and a deliverability hub into its Email plan. It costs $69 a month, or $55 billed yearly, with unlimited users and senders (lemlist.com/pricing, October 2026). The Multichannel plan is $109 a month, or $87 yearly.
The same plan includes a 650M+ lead database, an email and phone finder, an API and an MCP server and CLI. That makes it the only tool here with data, sending, warm-up and MCP in one subscription.
The trade-off is focus. lemlist is a sequencer first, and lead data runs on credits: the add-on is 2,000 credits for 400 emails or 100 phones.
Pros
- Warm-up, sequencer and finder in one price.
- Unlimited senders on the Email plan.
- API, CLI and an MCP server.
- Free trial, per the page.
Cons
- Sequencer-first, so warm-up is a feature, not the product.
- Lead data is credit-based.
- Warm-up limits are not itemised on the pricing page.
Best for: small teams that want one tool for sending, warm-up and a basic finder. Pricing: Email $69 a month, $55 billed yearly; Multichannel $109, $87 yearly (source, October 2026).
4. MailReach: best for per-mailbox reputation tracking
MailReach is a warm-up and deliverability tool, not a sequencer. The All-In-One plan starts at $25 per mailbox a month, with a 20% saving billed annually (mailreach.co/pricing, October 2026). It includes 20 spam-test credits.
It warms up to 100 emails a day per mailbox through a network of 30k real inboxes, and works with any provider that supports SMTP (mailreach.co/email-warmup, October 2026). It tracks reputation by provider and flags blacklist and DNS problems.
MailReach says plainly that it does not warm templates and does not warm by industry. That means fewer knobs than Warmup Inbox. Its API is free to call, and its docs list an MCP server for Claude, ChatGPT and Cursor (MailReach API docs, October 2026).
Pros
- Reputation view by provider, domain and tag.
- Spam tester included.
- Works with any SMTP provider.
- Honest about what warm-up can and cannot do.
Cons
- $25 per mailbox adds up past 20 inboxes.
- 100 warm-up emails a day is the lowest cap here.
- No sequencer, so you pay for sending elsewhere.
Best for: teams with a few high-value mailboxes that need reputation data. Pricing: $25 per mailbox a month, 20% off billed yearly (source, October 2026).
5. Warmy: best for teams that want an expert on call
Warmy sells one all-in-one deliverability plan from $49 a month. It has a 7-day free trial with no card (warmy.io/pricing, October 2026). Pricing is volume-based, so you pay for the warm-up emails you need generated.
The plan includes a Google Postmaster view, a reputation tracker, list verification, DMARC monitoring and full API access. Warmy cites a 1M+ mailbox network and a 500K+ US seed list that rotates monthly.
A dedicated deliverability expert and 24/7 human support are part of every plan. That is unusual at this price. The page does not name a per-mailbox rate, so model your cost with their team before you commit.
Pros
- Dedicated expert and 24/7 human support.
- Full API access on the entry plan.
- Postmaster data and DMARC monitoring included.
- 7-day trial with no card.
Cons
- Volume-based pricing is hard to forecast.
- No per-mailbox price published.
- No MCP server listed on the pricing page.
Best for: teams that want hands-on deliverability help, not just a switch. Pricing: from $49 a month (source, October 2026).
6. Warmup Inbox: best for the cheapest per-mailbox start
Warmup Inbox has three tiers. Basic is $15, Pro $49 and Max $79 per inbox a month at list price on the monthly view, and the annual toggle says it saves 20% (warmupinbox.com/pricing, October 2026). Every inbox you add lowers the average.
Daily warm-up messages cap at 75 on Basic, 250 on Pro and 1,000 on Max. The network is over 30K real inboxes. Basic includes the developers API, and Max adds unlimited API access.
Pro unlocks custom templates, warm-up topics, language warm-up and scheduled warm-up. If you need control over how the warm-up looks, this is the cheapest way to get it.
Pros
- Lowest entry price per inbox.
- Cap rises to 1,000 messages a day on Max.
- Custom templates, topics and language on Pro.
- 7-day trial, no card.
Cons
- Per-inbox pricing gets expensive at 50 mailboxes on Pro or Max.
- No MCP server listed.
- Basic cap of 75 messages a day is tight for aggressive ramps.
Best for: solo senders and small teams warming a handful of inboxes. Pricing: Basic $15, Pro $49, Max $79 per inbox a month (source, October 2026).
7. LeadOcean: best for the verified list behind the warm-up
LeadOcean does not warm mailboxes. We put it on this list because warm-up only protects a domain if the addresses you send to are real, and that is the part LeadOcean supplies. It is a people and company data API with 693M people, 366M with an email, and a hosted MCP server with 13 tools.
The emailStatus filter lets you pull only verified addresses, and count_leads sizes the list for free before you spend a record. For a ramp that sends 20 emails on day 1, you pull 20 verified rows, not 500. Work-email lookup is GET /v2/people/email/work, and bulk export is POST /v1/exports.
Pricing is flat. Free is $0 for 1,000 records for life. Solo is $97 a month, Agency is $497 a month and Platform is $1,997 a month, with a fair-use pace instead of credits. See pricing.
Pros
- Verified-only filtering through
emailStatus, with free counts. - 13 MCP tools, so an agent can pull the day's batch.
- Flat plans, no per-record price.
- Free tier: 1,000 records, no card, 5 requests a second.
Cons
- It does not warm, send or monitor mailboxes.
- Bulk CSV export is not on Free.
- You still need one of the six tools above.
Best for: anyone pulling a daily send list through an API, an agent or at volume. Pricing: Free $0, Solo $97, Agency $497, Platform $1,997 a month (leadocean.io/pricing, October 2026). Rate limits are 5, 50, 200 and 10,000 requests a second by plan.
Comparison table
| Tool | Best for | Starting price | Cost at 1M records a month | API | MCP | Rate limit |
|---|---|---|---|---|---|---|
| Instantly | Agencies with many mailboxes | $47 a month | Not applicable | Yes (API v2) | Yes | 100 a second, 6,000 a minute per workspace |
| Smartlead | Private pool, high send volume | $39 a month | Not applicable | Pro and up | Not listed | Not published on pricing page |
| lemlist | Warm-up plus sequencer | $69 a month, $55 yearly | Not applicable | Yes | Yes | Not published on pricing page |
| MailReach | Reputation tracking | $25 per mailbox a month | Not applicable | Yes | Yes | Not published on pricing page |
| Warmy | Expert support | $49 a month | Not applicable | Yes | Not listed | Not published on pricing page |
| Warmup Inbox | Lowest per-mailbox price | $15 per inbox a month | Not applicable | Yes (Basic and up) | Not listed | Not published on pricing page |
| LeadOcean | Verified list | Free, then $97 a month | $497 a month (Agency) | Yes | Yes (13 tools) | 5, 50, 200, 10,000 a second by plan |
"Not listed" means the pricing or feature page we read in October 2026 does not mention it. It does not mean the vendor has none.
How to choose
- Agency with 20+ mailboxes: Instantly or Smartlead, because mailbox count does not drive the price.
- Solo sender with 1 to 5 inboxes: Warmup Inbox for the lowest per-inbox price, or MailReach for reputation data.
- One tool for everything: lemlist, if you accept a sequencer-first product.
- Need a human to fix deliverability: Warmy.
- Script or agent workflow: pair any warm-up tool with LeadOcean for the daily verified batch, via API or MCP.
- Budget under $50 a month: Warmup Inbox Basic or Instantly Growth.
Verdict
Instantly wins for agencies that want warm-up and sending in one place. Smartlead wins when pool quality and send volume matter most. MailReach wins for a small set of mailboxes you cannot afford to burn, and Warmup Inbox wins on price per inbox. Warmy wins for teams that want an expert. lemlist wins for small teams that want one subscription. LeadOcean is not a warm-up tool and does not replace one, but it wins as the verified list that gives any of them something safe to send to. Read the schedule tools comparison next.
FAQ
Do I need a warm-up tool for cold email?
Yes for a new domain or mailbox, and for any mailbox you plan to send from at volume. The tool builds a history of wanted mail before you prospect. See inbox warm-up for the basics.
How long should I warm up before sending cold email?
Plan on two to four weeks for a new mailbox, ramping slowly. We cover the schedule in how long to warm up email.
Is a warm-up tool enough to land in the inbox?
No. Warm-up builds reputation, but a list full of invalid addresses will still raise your bounce rate. Send only to verified addresses and stop the ramp if bounces climb.
Which warm-up tool is cheapest?
Warmup Inbox Basic lists the lowest entry price at $15 per inbox a month. Instantly is cheapest when you run many mailboxes, because warm-up is unlimited on every outreach plan.
Can I script warm-up with an API or an agent?
Instantly, lemlist, MailReach and Warmy list API access, and Instantly, lemlist and MailReach list MCP. LeadOcean covers the list side through its API and 13 MCP tools. See automated email warm-up.
Does LeadOcean warm up my mailbox?
No. It supplies verified addresses and a free count, so each day's warm-up batch bounces less. Start on the pricing page.
Warm the mailbox, then send to addresses that will not bounce.
Free to start. No credit card. 1,000 records to spend whenever you like.
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