Cold Email Software for Agencies: The 8 Best Tools for Running Client Campaigns

The best cold email software for agencies is Smartlead for most shops, because one account holds unlimited mailboxes plus white-labeled client workspaces at $29 each. PlusVibe is the cheaper pick for agencies sending under 150,000 emails a month, and Email Bison fits agencies that already send 500,000+ emails and want isolated infrastructure on one flat bill. Instantly works well for agencies with a few large clients, but walling clients apart means one subscription per workspace.

Some tool links here are affiliate links (disclosure). Nerdy Joe is a certified Apollo.io Managed Services Partner and a PlusVibe Certified Silver Partner. We are not partners of Smartlead or Instantly.

Koldify, the done-for-you cold email agency behind Nerdy Joe, sends client campaigns on PlusVibe, Smartlead and Email Bison, which is why this guide focuses on agency mechanics. All prices are from vendor pricing pages and help centers as of October 2026.

What agencies need from cold email software

A tool that works for one sender can fall apart at ten clients. These are the features that matter once you run campaigns for other companies:

• Client workspaces: each client gets separate campaigns, leads, mailboxes and block lists.
• White label: clients log in on your domain with your logo, not the vendor's.
• Client access controls: clients can see reports and reply to leads without touching other clients' data.
• Unlimited inboxes: you will connect dozens or hundreds of mailboxes across clients, so per-mailbox fees kill margins.
• Infrastructure separation: dedicated IPs or servers per client protect one client from another's reputation.
• Billing that maps to clients: per-client invoices, credit splits or a flat bill you can mark up.
• API and webhooks: to push replies into client CRMs and your own reporting.

Agency features compared

What 5 and 10 clients cost

This is our arithmetic from list prices, monthly billing, as of October 2026. It covers software only, not domains, mailboxes or lead data, and assumes the clients share the plan's email volume.

The PlusVibe figure assumes the first workspace is included and the rest start at $29; the pricing page says "from $29" without explaining how it scales. The Instantly figure assumes each client needs isolated data, since one agency portal per workspace shows every campaign in that workspace.

The cheapest option depends on how much each client sends. Instantly costs more per client but gives every client its own 125,000-email allowance, while Email Bison only makes sense once total volume approaches 500,000.

1. Smartlead: best overall for agencies

Smartlead treats agencies as its core audience. All plans include unlimited email accounts, and client workspaces with white label cost $29 per month each from Pro up.

Pricing as of October 2026: Base $39, Pro $94, Unlimited Smart $174 and Unlimited Prime $379 per month, with 17% off annually. Prime includes three client workspaces, three SmartServers, a dedicated manager and a private Slack channel.

Agency features:

• White label on your own domain with your logo; clients can view reports and campaigns and reply from the master inbox
• Role-based client permissions
• Set your own pricing packages for clients and divide lead credits across them
• No per-seat fees for your team
• SmartServers (dedicated servers with dedicated IPs) at $39 per server per month, assignable to individual clients
• Up to 25 named admin API keys, plus webhooks from Pro

Watch out for: a learning curve that reviewers mention often, and a Fair Use Policy that still lists mailbox caps under older plan names. Placement testing (SmartDelivery) and mailboxes are extra.

Best for: Agencies with 5 to 50 clients that want everything in one account. Read our Smartlead review or open a Smartlead trial.

2. PlusVibe: best value for small and mid-size agencies

PlusVibe's own partner material says it is built for lead gen agencies with 3 to 30 clients. Its Business plan includes 150,000 emails and 100,000 active leads for $77 a month, which leaves room for several small clients on one plan.

Pricing as of October 2026: Personal $37, Business $77 and Agency from $497 per month, with two months free on annual billing. Business includes one workspace, with extra workspaces from $29 per month.

Agency features:

• Unlimited team members on every plan, with member roles
• A White Label Client App on Business and Agency: a branded mobile inbox where clients read and answer replies, with no charge to the client
• White-label positive-reply notifications on Business and Agency
• On Agency: dedicated client workspaces, white labeling for each client, isolated sending servers, dedicated IPs and a private Slack channel
• API and webhooks from Business

Watch out for: white label gating is inconsistent across PlusVibe's own pages (the pricing page lists it on Agency only, while the help center places the client app on Business too). There is no lead database, placement testing is a paid add-on from $19 per month, and the pricing page does not state a mailbox cap.

Best for: Agencies under 150,000 emails a month that bring their own data. Read our PlusVibe review, see PlusVibe vs Smartlead, or try PlusVibe.

3. Instantly: best for agencies with a few large clients

Instantly includes white label on its Hypergrowth ($97) and Light Speed ($358) plans with no extra fee listed. Clients log in on your subdomain after you point a CNAME record to Instantly's agency host.

What clients can access: Campaigns (view or edit), Unibox, Analytics, CRM and Blocklist, granted individually or all together.

The key limit: each workspace supports one agency portal, and clients with campaign access see every campaign in that workspace. Instantly's help center recommends separate workspaces for clients who need separate data, and each workspace needs its own subscription.

Strengths for agencies: a 450M+ contact database through Credits, AI reply and sales agents, and a September 2026 redesign that added multi-workspace management with combined reporting. Hyper Credits and Inbox Placement plans can be shared across sub-workspaces.

Watch out for: cost per client climbs fast if every client needs isolation, and lead data, CRM and placement testing are separate subscriptions.

Best for: Agencies with a handful of high-volume clients. Read our Instantly review or try Instantly.

4. Email Bison: best for high-volume agencies

Email Bison sells one plan at $599 per month that includes 500,000 emails, unlimited workspaces and unlimited teammates. The homepage promises complete data isolation for every client and routing across dedicated IP pools.

Agency features: unlimited client workspaces, isolated infrastructure with dedicated IPs, private warmup, full API access and an EmailGuard integration for placement testing. A third-party directory describes a white-label interface with a custom domain and logo, but Email Bison's own homepage does not mention white label, so confirm it on a demo.

Watch out for: no lead database and no published free trial. Below a few hundred thousand emails a month, the flat price is hard to justify.

Best for: Agencies already sending at scale that want one predictable bill.

5. Woodpecker: best for billing per client

Woodpecker has a dedicated Agency Panel at $27 per active client per month, plus white label at $5 per active client. The panel includes a separate prospect database per client, bulk campaign actions, bulk mailbox upload, a global blacklist, view-only client access, automated domain audits and centralized billing.

Pricing as of October 2026: the base plan is priced by contacted prospects with a calculator (it showed $7 per 100 contacted prospects per month when we checked) and includes unlimited email accounts. Clients can connect their mailboxes without sharing passwords.

Watch out for: only 4 warmups are included, with more at $5 per mailbox per month, which adds up across many client inboxes.

Best for: Agencies whose clients send to small, targeted lists.

6. Reply.io: best for multichannel agencies

Reply.io offers agency plans that are not priced per seat. Agency Core is listed from $210 per month (the summary card on the same page shows $166) with unlimited clients, users and mailboxes, and LinkedIn at $69 per account.

Agency features: white label as an option on Agency Core (price on request), and an Agency AI SDR plan from $500 per month per client.

Watch out for: the white label price is not published, and the two Agency Core prices on one page make it worth confirming in writing.

Best for: Agencies selling email plus LinkedIn programs.

7. Saleshandy: best budget option for many small clients

Saleshandy says you can manage unlimited clients and connect unlimited email accounts at no extra cost. Starter is $41 per month and Pro is $99, both with lead finder credits included.

Agency features: a central dashboard for all clients and teams, shareable performance analytics and white label with your brand, logo, colors and custom domain. The pricing page places white label on the custom-priced Enterprise plan.

Watch out for: white label requires a sales conversation, and the free trial is 7 days.

Best for: Agencies with many low-volume clients on a tight budget.

8. lemlist: best for agencies built on LinkedIn plus email

lemlist runs agencies through an Agency Cockpit, where each client is a separate team with its own campaigns, leads and unsubscribe lists. Each team gets its own monthly invoice and can use its own payment card.

Pricing as of October 2026: Email $69 per user per month and Multichannel $109, billed per paid seat. Admin seats are free if the user connects no mailbox and sends no campaigns, and external users get passwordless, report-only access.

Watch out for: per-seat pricing across many clients, and no white label in lemlist's agency documentation.

Best for: Agencies whose offer depends on LinkedIn steps.

How to set up client separation the right way

Whatever tool you pick, the structure matters more than the brand:

1. One workspace or team per client. Keep leads, block lists and reports apart so nothing leaks.
2. Separate domains and mailboxes per client. Never send two clients' campaigns from the same domain.
3. Separate tracking domains. Most tools let you set a custom tracking domain per workspace or sending domain.
4. Client-level block lists. Load each client's customers and open deals before the first send.
5. Reply routing. Decide who answers replies, then use client access, a client app or CRM webhooks to deliver them.

Our guide to cold email infrastructure covers domain and mailbox setup in detail, and the full best cold email software roundup covers non-agency picks.

Rather not run it yourself?

If you run a marketing or sales agency and want to offer outbound without building the delivery team, Koldify can run campaigns behind the scenes. Book a 30-minute call with David at Koldify through the Koldify intro calendar to talk it through.

The verdict

Start with Smartlead if you want the most complete agency toolkit in one account. Pick PlusVibe if your clients are smaller and you want the lowest cost per email under 150,000 a month. Move to Email Bison once total volume nears 500,000 emails, and use Instantly when a few big clients each need their own space and you value its data and AI features.

Sources

• Smartlead pricing
• Smartlead pricing.md
• Smartlead white labelling
• Smartlead University: Client access and white labeling
• Smartlead cold email infrastructure
• Smartlead APIs and automation
• Smartlead Fair Use Policy
• PlusVibe pricing
• PlusVibe Help: White Label Client App FAQ
• PlusVibe Help: New features, March 2026
• PlusVibe Help: Workspaces and member roles
• PlusVibe Help: Email placement test FAQ
• Instantly pricing
• Instantly Help: Agency white labeling
• Instantly Help: Outreach plans comparison
• Instantly changelog
• Email Bison
• Email Bison pricing
• The GTM Directory: Email Bison
• Woodpecker
• Woodpecker pricing
• Reply.io
• Reply.io pricing
• Saleshandy
• Saleshandy pricing
• Saleshandy for agencies
• lemlist
• lemlist pricing
• lemlist Help: Agency Cockpit and roles
• lemlist: Why agencies love lemlist