Key points we’ll cover in this article
- Cost model: Instantly = flat fee with unlimited email accounts, Apollo = per‑seat ($49–$119/user/mo). Instantly scales predictably, Apollo costs climb with your team and client roster.
- Deliverability: Instantly’s AI warm‑up + 4.2 million account network and SISR (Server & IP Sharding & Rotation) protect sender reputation at scale. Apollo offers warm‑up and ramp‑up, but you’ll still manage per‑user limits.
- Agency ops: Instantly has white‑label client portals (custom domain, branded access) and a Unibox to manage all client replies in one place.
- Data: Instantly’s Lead Finder surfaces 450M+ contacts inside the app. Apollo’s database is 210M+ verified contacts with robust intent signals.
- Best fit: If your agency lives on cold email economics (more accounts, more volume, consistent inboxing), Instantly wins. If you need a broader sales stack with heavy CRM workflows and multichannel tasks, Apollo is compelling.
Why agencies struggle with cold email at scale
As your client list grows, three things start to hurt:
- Costs compound: every new sender, SDR, or client seat increases your monthly bill.
- Deliverability risk: 2024+ Gmail/Yahoo rules require authenticated sending, easy one‑click unsubscribes, and keeping spam complaints low (Gmail calls out a complaint‑rate threshold).
- Ops friction: juggling multiple domains, mailboxes, and client threads across tools.
The right platform should remove those limits, not magnify them. Let's take a look at how Instantly and Apollo compare.
How Instantly is built for agency scalability
1) Flat‑fee pricing with unlimited accounts
On Growth/Hypergrowth, you can connect unlimited email accounts under one subscription - no per‑seat tax. For agencies, that’s the difference between “we can add three more client domains today” versus “let’s get approval for more user licenses and hurt our margins.”
2) Deliverability that scales with you
Instantly’s warm‑up runs on a 4.2M+ account network to build reputation using human‑like engagement (opens/replies/threads), with headless browsers for realistic patterns. Pair that with SISR (Server & IP Sharding & Rotation) for isolation and proactive IP management, and you get inbox placement that holds at volume.
3) Agency‑ready collaboration (white‑label)
Spin up a branded client portal on your own subdomain and share only what clients need (Campaigns, Unibox, Analytics, CRM). It’s how you package your outbound as a clean, on‑brand service.
4) Lead sourcing inside the same workspace
The integrated Lead Finder lists 450M+ contacts (with “pay only for verified leads”), so your team sources, verifies, and launches campaigns without hopping tools. We think it's crazy that some platforms charge for unverified leads.
5) Automation and personalization in minutes
Instantly's new AI Copilot helps you automatically produce multi-step sequences and safe copy variations at scale, with a chat-based module so you can 'talk' with your campaigns to understand performance and get advice on campaign improvements. Less repetitive writing, more deliverability-optimized campaigns created for you.
What Apollo does well (and where trade‑offs appear)
Apollo is an impressive sales intelligence + engagement platform:
- Database: 210M+ verified contacts, plus Buying Intent signals (Bombora‑powered) for timing outreach.
- Multichannel sequences: Combine email, calls, and LinkedIn tasks in one workflow - strong for SDR teams running full sequences.
- CRM depth: Native integrations with Salesforce, HubSpot, and Pipedrive - good field mapping and bi‑directional sync.
- Deliverability: Email warm‑up and Inbox Ramp‑Up are available; however, mailbox counts are per user (up to 15 mailboxes per user, plan‑dependent).
Trade‑off for agencies: Apollo’s per‑seat pricing ($49 / $79 / $119 per user per month, paid annually) plus data credits makes costs scale with people instead of performance. For multi‑client agencies, that usually means higher, less‑predictable spend as you grow.
"Compared to other outbound tools - it's an expensive tool" - Apollo user on G2 (08/16/2025)
Read the full view on G2
Head‑to‑head for agencies
Pricing & scale
- Instantly: Flat fee (e.g., $97/mo Hypergrowth) with unlimited email accounts - add as many client domains/mailboxes as needed without adding seats.
- Apollo: Per‑seat plans ($49–$119/user/mo). If you add 5 SDRs or grant clients access, your cost rises linearly and export/data credits add variability.
A practical example to model: A 6‑person delivery team & 10+ client mailboxes
- Instantly: still $97/mo on Hypergrowth.
- Apollo: at $79/user (typical mid‑tier), $474/mo just in seats before any overages or add‑ons and that's on their annual subscription, monthly would cost $594/mo (Illustrative math based on listed plan rates.)
Deliverability
- Instantly: 4.2M+ account warm‑up network + SISR for IP isolation & rotation, plus inbox rotation across unlimited accounts - designed for high‑volume, multi‑client sending.
- Apollo: Email warm‑up/inbox ramp‑up available, but mailbox counts are per user and warm‑up volume is capped by recommended daily settings.
"Getting unreal open rates on the outbound due to the various features they have to increase deliverability, this platform is the one. Try it out for yourself, you won't be disappointed." - Instantly user on G2 (07/24/2025)
Read the full view on G2
Lead generation
- Instantly: 450M+ contacts inside the app with “only pay for verified leads.” which minimizes budget waste.
- Apollo: 210M+ verified contacts (+ intent). If you need advanced filtering and intent‑led targeting across a full sales cycle, Apollo shines.
"I noticed that one of them had a crazy high bounce rate of 80%. The weird part is that those email addresses were from Apollo.io's verified leads database." - Apollo user on Reddit (December 2024)
Read the full view on Reddit
Agency operations
- Instantly: White‑label client portal on your domain - Unibox consolidates every client reply in one place (with AI reply labels/macros), native CRM and integrations with popular CRMs like HubSpot, Pipedrive and Salesforce
- Apollo: Strong multichannel SDR workflows and CRM integrations - excellent if your team lives in Salesforce/HubSpot and phones + LinkedIn are core motions
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Feature comparison (at a glance)
| Capability | Instantly | Apollo |
|---|---|---|
| Pricing model | Flat fee: unlimited email accounts on all plans | Per‑seat tiers ($49–$119/user/mo) |
| Deliverability engine | AI warm‑up via 4.2M+ account network, SISR for IP sharding & rotation | Warm‑up + inbox ramp‑up, mailbox caps per user (up to 15) |
| Lead database | 450M+ contacts in Lead Finder (pay for verified only) | 210M+ verified contacts + Buying Intent |
| Agency tooling | White‑label client portal, Unibox across accounts, share global credits across clients, native CRM | CRM integrations, multichannel sequences |
| Multichannel outreach | Email (plus reply automation via Unibox) | Email + calls + LinkedIn tasks in one sequence |
When to choose which
Pick Instantly if you:
- Need predictable economics to add more domains/mailboxes as clients grow.
- Want out‑of‑the‑box deliverability (AI warm‑up + SISR) tuned for cold email at volume
- Value white‑label client experiences and a clean shared inbox for your team
Consider Apollo if you:
- Need a broader GTM platform (data + engagement + dialer + LinkedIn tasks).
- Live deeply inside Salesforce/HubSpot, where bi‑directional sync is critical
- Are okay with per‑seat licensing and mailbox caps as you scale the team
Practical pricing scenario
Agency A runs 12 domains across 8 clients and has 6 team members:
- Instantly (Hypergrowth): $97/mo total, add more mailboxes without extra costs
- Apollo (Professional @ $79/user): $474/mo in seats, before any export/mobile credits
Takeaway: If your unit economics hinge on more mailboxes, Instantly compounds margin as you scale and has better ROI.
My verdict
If your agency’s pipeline relies on high‑volume, deliverability‑first cold email, Instantly is the strategic pick. The unlimited‑account model and SISR‑backed deliverability remove the two biggest ceilings: cost per seat and inbox placement, so you can scale client campaigns confidently. Use Apollo when your requirement tilts toward full‑stack sales engagement across phone/LinkedIn with deep CRM ops.
Ready to test it with your own numbers?
Start your free Instantly trial and connect a few client domains. See how quickly you can warm up and launch without paying extra for headcount.
Frequently Asked Questions
Q: Is Instantly really unlimited accounts on a flat fee?
A: Yes - on Growth and higher you can connect unlimited email accounts under one subscription. That’s the core agency advantage.
Q: Does Apollo have warm‑up?
A: Yes. Apollo provides Email Warmup and Inbox Ramp‑Up with configurable daily volumes; note mailbox caps are per user (up to 15 per plan).
Q: What database sizes should I plan around?
A: Instantly Lead Finder advertises 450M+ contacts; Apollo lists 210M+ verified contacts. Your best choice depends on workflows and targeting needs.
Q: Do I get agency‑friendly client access with Instantly?
A: Yes - white‑label client portals on your own subdomain let you share selected dashboards and inboxes with clients. Instantly is a popular choice for agencies.
