TL;DR

• Instantly: Flat‑fee, unlimited email accounts, built‑in warmup, 450M+ B2B contacts (SuperSearch), and new AI Reply Agent. Best for predictable scale, deliverability across many client inboxes and you want one paltform for data + outreach.
• Smartlead: Email‑first automation with unlimited mailboxes and AI warmup on all plans. Best for centralized sending pools when you already have leads from other software.
• Lemlist: Strong multichannel (email + LinkedIn steps) and visual personalization, lemwarm warmup is included per seat. Best for creative, multistep sequences, priced per user.
• Apollo: Big integrated sales intelligence + outreach with 210M+ contacts and now built‑in warmup. Best when data + email + dialer live in one stack priced per user/credits which can get expensive.
• Reply.io: Mature multichannel (email, LinkedIn, calls, SMS, WhatsApp). Best for teams standardizing full‑funnel outreach typically per user on core plans.

Why agencies are re‑evaluating Lemlist in 2025

As an ex-agency operator, scaling cold email used to break our margins and reputation at once: per‑seat pricing ballooned costs, and deliverability moved beneath our feet with every provider change. That’s why Instantly is built around unlimited accounts and deliverability by default because agencies shouldn’t be punished for growing.

1) The “scale tax” of per‑seat pricing

Per‑seat tools are smooth at 2 seats and painful at 20. Lemlist’s Email Pro is $69/user/month, and multichannel jumps higher. Headcount growth = immediate software cost doubling you’re taxed twice if you add sending identities and client mailboxes. A flat‑fee plan keeps Total Cost of Ownership (TCO) predictable as you add inboxes.

2) Deliverability rules got stricter (and clearer)

Gmail and Yahoo tightened the screws in 2024–2025: SPF/DKIM/DMARC alignment, one‑click unsubscribe (commercial senders over 5,000/day), and spam complaints under 0.3% sustained above that and you’re ineligible for remediation. Translation: without proper setup and warmup, your campaigns stall no matter how great your copy is.

"160 billion spam emails are sent every day, with 46% of the 347 billion daily emails sent" - EmailTooltester.com

3) Personalization that actually moves reply rates

Token‑stuffed templates are invisible. What works in 2025: short, specific openings tied to real context, then persistent follow‑ups. (AI can help if it’s fed fresh firmographic data.) That’s why we ship tools that combine B2B data + AI sequence writing you get relevance at scale without busywork.

4) Tool sprawl hurts speed (and data quality)

Agencies juggling a database, verifier, sender, and CRM lose hours to glue work. An integrated workflow of lead search -> verification -> email sending -> reply management cuts setup time and preserves deliverability context while avoiding the spaghetti mess of multiple tools glued together.

The top Lemlist alternatives for agencies (deep dive)

Instantly: predictable scale & deliverability for multi‑client agencies

We built Instantly so you can connect unlimited email accounts under a flat monthly plan, warm them up automatically, find prospects from a 450M+ contact database, and let AI handle tedious steps like drafting replies. It’s the agency‑friendly way to add inboxes and clients without multiplying software seats.

Why agencies pick it:

• Flat‑fee economics with unlimited email accounts. Scale client inboxes without adding per‑seat licenses or per‑mailbox fees, unlimited accounts and warmup are included on Instantly’s Email Outreach plans. This keeps your TCO predictable as you grow team members and domains.
• Deliverability by default (built‑in warmup + ramp guidance). One‑click, automated warmup helps new domains/inboxes build reputation the help center documents ramp time best practices. If you need it, Instantly can also provision deliverability‑optimized Google accounts with SPF/DKIM/DMARC set to best practice.
• Integrated B2B data at scale. SuperSearch gives you 450M+ contacts with waterfall enrichment (multiple providers) and AI‑powered research/personalization so you can find, enrich, and launch from one place.
• AI that handles the grunt work. AI Reply Agent auto‑replies, shares your calendar, and follows up AI Inbox Manager schedules timely replies so leads don’t wait while you’re asleep.
• Unified reply management + easy handoffs. Unibox centralizes replies from all connected accounts, while Zapier/CRM recipes push “Interested” leads into HubSpot, Close, Pipedrive, Slack, and more.

What's missing: Instantly is email‑first, if you need native LinkedIn/SMS/calls outreach, you'll need to integrate them with Instantly.

Smartlead: high‑volume email automation, unlimited mailboxes

Smartlead is an email‑first platform that emphasizes scale and deliverability. Core differentiators for agencies include unlimited mailboxes, unlimited warmups, a central Unibox for reply handling, and a flat‑fee model that doesn’t tax you per additional inbox. Native tools cover DNS checks (SPF/DKIM/DMARC), blacklist checks, and built‑in verification to keep bounce rates down.

Why agencies pick it:

• Unlimited mailboxes & warmups on all plans without per‑account fees.
• Deliverability controls (ramped warmup, high‑deliverability IPs, Unibox, blacklist/DNS tools) streamline setup and monitoring.
• Workflow glue: API + webhooks and native integrations (HubSpot, Salesforce, Pipedrive, Zapier/Make/N8N) reduce tool sprawl.

What’s missing:

• No native B2B contact database. Smartlead states it does not provide lead sources. You will need an external data provider or enrichment workflow.
• No all‑in‑one multichannel canvas. For LinkedIn steps, teams typically pair Smartlead with a LinkedIn tool like Expandi and pass leads between the two. Smartlead’s own content emphasizes integrations via Zapier, Make, and n8n rather than native LinkedIn automation.
• External email‑finder guidance. Smartlead’s blog points users to third‑party email finders such as Hunter, Snov, Lusha, and Skrapp for data capture.

Apollo: integrated data + outreach (per‑seat)

What it is: Apollo is a sales intelligence + engagement platform. The headline is its B2B database (~210M+ contacts, 35M+ companies) paired with sequences, a dialer, and now built‑in email warmup/inbox ramp. If you want prospecting, enrichment, and outreach in one system, Apollo’s breadth is tough to beat.

Why agencies pick it:

• Large, integrated dataset for discovery and enrichment, plus Chrome extension for LinkedIn prospecting.
• Multichannel sequences with email, calls (dialer), and LinkedIn tasks inside a single workflow.
• Deliverability tooling: native warmup/ramp options to help new inboxes build reputation.

What’s missing

• Flat‑fee + unlimited accounts. Apollo is per‑seat and credit‑based.
• Mass mailbox rotation on a single seat. Apollo lets you add up to 15 mailboxes per user (plan‑dependent) useful, but not unlimited accounts.
• LinkedIn execution isn’t fully automated. Apollo includes LinkedIn steps/tasks and a Chrome extension to act on them, but those steps rely on tasking/extension flows not the fully integrated, automated multichannel actions you get in dedicated multichannel suites.

Reply.io: multichannel sequences for complex plays

Reply is a multichannel sales engagement platform that standardizes email, LinkedIn, calls, SMS, and WhatsApp in one canvas. It offers AI helpers (e.g., Jason AI SDR), deliverability tooling (SPF/DKIM/DMARC guidance, inbox rotation, health checks), and flexible plans to match channel mix and volume.

Why agencies pick it:

• True multichannel with semi‑automated LinkedIn tasks, calls/SMS, and WhatsApp in one sequence UI.
• Deliverability suite built in (warmup via partner, inbox rotation, Google Postmaster integration, custom tracking domains) to protect sender reputation at scale.
• Plan flexibility: can include unlimited mailboxes, multichannel only includes 5 mailboxes per user and bundles channels, LinkedIn automation is a paid add‑on on many tiers, calls/SMS add‑on available.

What’s missing

• Truly consolidated pricing for multichannel at scale. Reply’s Multichannel All‑Inclusive is priced per user and caps Email Automation at 5 mailboxes per user, LinkedIn and Calls/SMS can add extra per‑account costs so TCO rises with users and channels. (On the Email Volume plan you can get unlimited mailboxes, but that plan is email‑only.)
• Data credits are limited on base plans. Reply includes 50 Live Data credits/month. Heavy prospecting typically requires additional data credit purchases.
• Warmup is via an integrated partner. Email warmup is included but delivered through Mailtoaster. It works, but if you prefer first‑party deliverability networks over partner integrations, note the difference.

Where Lemlist itself shines (and the trade‑offs)

Lemlist brings multichannel sequences (including LinkedIn steps) and visual personalization. Lemwarm is included with each paid seat. But it’s still per‑user and, by default, 3 sending emails per user (you can add more for a fee).

What do users say?

“Reliable service, deliverability has been stellar, and launching or modifying a campaign takes minutes.” - G2 review for Instantly

“By using the warmup tool, deliverability is improving day by day.” - G2 review for Instantly

“I feel that the product is expensive compared to the competition.” - G2 review on Lemlist

“Lemwarm doesn’t pull emails out of the spam or category filters. It may be the worst warm up service I’ve ever seen. Don’t use it.” - Reddit user in r/coldemail

10‑day migration plan from Lemlist (safe and low‑risk)

Days 1–2: Export & verify
Export all campaigns, suppression lists, and reply histories. Run lists through a verifier remove invalids before any platform import.

Days 2–3: Connect & authenticate
Connect domains and publish SPF, DKIM, DMARC records. Validate alignment in Google Postmaster Tools.

Days 3–10: Warmup
Enable automated warmup on all new inboxes. Do not send campaigns until warmup completes its initial ramp.

Days 8–10: Pilot & monitor
Send 50–100 emails to a high‑intent segment. Track inbox placement, opens, bounces, and spam reports (<0.3%).

Day 10+: Phased rollout
If pilot metrics are healthy, scale volume gradually. Keep Lemlist active for 72 hours to catch stragglers.

Flat‑fee vs per‑seat: TCO snapshot (example math)

Let’s compare monthly costs for a 10‑person team:

• Per‑seat (e.g., Lemlist Email Pro $69/user/month): $690/mo (adds up linearly as you hire). Multichannel tiers cost upwards off $99/user/month.
• Flat‑fee (e.g., Instantly Hypergrowth $97/mo): $97/mo for unlimited accounts within plan limits if you outgrow it, Light Speed is $358/mo for higher volume.

Takeaway: If you manage many inboxes across clients, flat‑fee wins on TCO and reduces license friction as you scale.

From one operator to another

I've been an agency founder frustrated by per‑seat tools and fragile deliverability, then joined Instantly where we've built around what agencies actually need: unlimited accounts, built‑in warmup, integrated data, and AI to remove repetitive work all without VC strings. If that sounds like the operating system your agency needs, we’d love to help

Spin up a 14‑day pilot: warm 3–5 inboxes, send a 100‑lead test, and compare placement vs your current tool. Try Instantly free connect unlimited accounts and see if flat‑fee scale fits your model.

FAQs

What changed with Gmail/Yahoo and why does it matter for cold email?
Bulk senders must keep spam complaint rates <0.3%, authenticate with SPF/DKIM/DMARC, and enable one‑click unsubscribe. Failing those raises the odds your campaigns are routed to spam or blocked.

Does warmup still help after the 2024 rules?
Warmup is not a magic wand, but done alongside list quality, throttled ramp, and aligned DNS, it helps new/parked inboxes establish baseline reputation so legitimate outreach lands in inboxes.

Which tools include warmup natively?
Instantly, Smartlead, Apollo, Reply, Lemlist (via lemwarm) all provide warmup. The difference is pricing model (flat vs per‑seat) and how many inboxes you can warm without add‑ons.

If I need LinkedIn steps, do I have to leave Instantly?
No, you can keep email at scale in Instantly and run LinkedIn/calls via dedicated tools (Reply, Lemlist) or CRM workflows. If you want everything in one multichannel sequence UI, Reply/Lemlist are built for that.