Smartlead vs Warmbox (2026): which should you pick?

Pick Smartlead if

• Fits if you run cold email for several clients and want each in its own workspace
• Works for senders who spread big campaigns across dozens of mailboxes

Look elsewhere if

• Skip it if you want LinkedIn steps built in, as Smartlead is email only
• Tight if you stay on Base, with 2,000 contacts and no CRM, API or webhooks
• Pricey if you add the extras, as inbox tests start at $49 a month and servers cost $39 each
• Watch out: verified lead emails are $59 a month extra on Base and Pro, and verification is sold in packs from $32
• Watch out: there's no free plan, and the trial stops at 2,500 sends and 1,250 contacts with white labeling locked

Pick Warmbox if

• Fits if you send cold email from one or two new mailboxes and want a warm-up run in the background
• Works for agencies that connect many client inboxes and will ask for a custom plan

Look elsewhere if

• Skip it if you want a free try, because there is no trial or free plan
• Tight if you run more than 6 inboxes, as plans stop there and larger setups are custom
• Pricey if you add inboxes: $15 for 1 inbox becomes $69 for 3
• Watch out: the vendor says warm-up usually needs 15 to 30 days of uninterrupted running before results show
• Watch out: the pricing page doesn't say which billing period each of its two price sets applies to

Smartlead

• Base has no CRM, API or webhooks and stores only 2,000 contacts.
• Verified lead emails cost $59 a month extra on Base and Pro, and email verification is sold separately in credit packs from $32.
• Inbox placement tests (SmartDelivery, from $49 a month), dedicated servers ($39 each a month) and calling credits (from $9 a month) cost extra.
• There is no free plan; the 14-day trial allows 2,500 sends and 1,250 contacts and leaves out white labeling.

Warmbox

• The pricing page does not state which billing period each of its two price sets applies to; the default view shows $15 for Solo and the other toggle shows $19.
• Plans are sized by the number of inboxes (1, 3 or 6) and by emails a day, so larger setups need a custom plan.
• The vendor says warm-up usually takes 15 to 30 days of uninterrupted warming before results show.
• It warms mailboxes only; it does not send campaigns or find leads.

Smartlead

Unlimited mailboxes with rotation

Every plan connects any number of email accounts, warms them up and spreads a campaign's sends across them to protect each sender's reputation.

Unified master inbox

Replies from all accounts land in one inbox sorted by intent, with bulk actions and Kanban deal tracking. CRM access starts at Pro.

SmartProspect lead finder

A built-in B2B lead finder. Verified prospect emails are included on Unlimited Smart and Prime and are a $59 a month add-on on Base and Pro.

SmartAgents and SmartAssistant

AI agents and an assistant create campaigns, watch warmup and mailbox health, find leads and sort replies, on every plan including the trial.

Client workspaces and white labeling

From Pro, agencies run each client in its own workspace under their own brand for $29 a month per workspace; Unlimited Prime includes 3.

API, webhooks and MCP

Pro and above include the API and webhooks, and an MCP server gives AI assistants such as Claude access to campaigns, mailboxes and leads.

Warmbox

Automated warm-up traffic

Sends and answers messages with a private inbox network, marks them as favorites and removes them from spam.

Warm-up profiles

Growth, flat or random volume patterns, a warm-up schedule and fully custom settings.

Realistic content

The page says replies are written to look human, using GPT-4 and a hybrid approach.

Checks and monitoring

A live email checker for DNS and blacklists, spam score monitoring and a reporting dashboard.

Many inbox types

Gmail and Google Workspace by OAuth, Microsoft 365, Yahoo, iCloud, AOL, Zoho, SendGrid, Mailgun, Amazon SES and any SMTP mailbox.

Agency use

Multi-account support for agencies and team members on every plan.

Smartlead

• Base$32

  per month for 6,000 emails, billed yearly ($39 monthly)

  2,000 stored contacts, unlimited mailboxes and warmup. No CRM, API or webhooks; 2,000 verified prospect emails are a $59 a month add-on.

• Pro$78

  per month for 90,000 emails, billed yearly ($94 monthly)

  30,000 contacts, CRM, API and webhooks, and client workspaces at $29 a month each. 30,000 verified prospect emails are a $59 add-on.

• Unlimited Smart$144

  per month for 150,000 emails, billed yearly ($174 monthly)

  Unlimited contacts, the premium warmup pool, calls with a customer success manager and 50,000 verified prospect emails included.

• Unlimited Prime$315

  per month for 500,000 emails, billed yearly ($379 monthly)

  170,000 verified prospect emails, 3 dedicated SmartServers, 3 client workspaces, a dedicated manager and a private Slack channel.

Warmbox

• Solo$15

  per month for 1 inbox, billing basis unclear

  1 inbox warmed at up to 50 emails a day, 1 member and premium support. The page's other toggle lists $19.

• Start-up$69

  per month for 3 inboxes, billing basis unclear

  3 inboxes at up to 250 emails a day, 3 team members and premium support. The other toggle lists $79.

• Growth$139

  per month for 6 inboxes, billing basis unclear

  6 inboxes at up to 500 emails a day, 6 team members and enterprise support. The other toggle lists $159.

• TeamCustom

  Custom plans for larger sending volumes, quoted through the vendor's chat.

Smartlead

• Annual discount

  Save 17% with yearly billing

  Billed yearly, Base is $32 a month instead of $39, Pro $78 instead of $94, Unlimited Smart $144 instead of $174 and Unlimited Prime $315 instead of $379.

• Other savings

  50% off the first month

  The pricing page offers new sign-ups 50% off their first month on any plan, with no end date shown.

Warmbox

No public discounts listed.