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Cold Email Infrastructure Google Workspace Instantly.ai Email Setup at Scale

600 Email Accounts Set Up in
Under One Week. 100% Health Score.

ClientOutboundBin · Cold Email Agency
Engagement TypeContractual · Client Fulfillment
ServicesCold Email Infrastructure Setup
Scale600 / 1,000 / 2,000 accounts
3,600

Total accounts set up across projects

300K

Emails/month capacity (600 setup)

100%

Health score on all accounts

80%+

Open rate from day one

The Challenge

Scale Fast. Don't Break Anything.

OutboundBin is a cold email agency that runs outreach campaigns at scale for clients. When they needed infrastructure built rapidly across multiple projects simultaneously, they brought me in on a contractual basis for client fulfillment. The brief was deceptively simple: set up hundreds of email accounts, fast, with every single one configured correctly and warming up cleanly before campaigns launched.

The challenge wasn't just the volume — it was maintaining quality under tight deadlines. At this scale, a single misconfigured DNS record, a wrong warmup setting, or a poorly structured workspace can cascade into deliverability failures across hundreds of accounts. Speed was required. So was precision. Both, at the same time.

The brief: Set up cold email infrastructure at scale — domains, Google Workspace, DNS records, Instantly.ai warmup — for multiple client projects. No compromises on health score or deliverability. Meet the deadline.

Projects Completed

Three Infrastructure Projects. Three Deadlines Met.

Across the OutboundBin engagement, I set up multiple cold email infrastructure projects — each at a different scale, each with its own deadline, each delivered with a 100% health score across all accounts.

600
Email accounts set up in under one week
300K emails/month capacity · 100% health score
1,000
Email accounts — second project
500K emails/month capacity · 100% health score
2,000
Email accounts — third project
1M emails/month capacity · 100% health score
600 Accounts — Instantly.ai Dashboard (Health Score 100%)
OutboundBin 600 email accounts in Instantly.ai with 100% health score
1,000 Accounts — Instantly.ai Dashboard (Health Score 100%)
OutboundBin 1,000 email accounts in Instantly.ai with 100% health score
2,000 Accounts — Instantly.ai Dashboard (Health Score 100%)
OutboundBin 2,000 email accounts in Instantly.ai with 100% health score
How I Did It

The Exact Process Behind 600 Accounts in One Week

Setting up cold email infrastructure at this scale isn't just clicking buttons — every layer has to be right before the next one begins. Here's the exact process I followed for the 600-account project, which became the template for the 1K and 2K setups that followed.

1
Domain Registration
Registered 150 domains via Namecheap — the most efficient registrar for bulk domain management. Namecheap's UI makes it fast to configure DNS records at scale without switching between multiple dashboards.
Math: 150 domains × 4 email accounts each = 600 accounts. All domains registered as .com for maximum deliverability trust signals.
2
Google Workspace Setup (Reseller Account)
Created 15 Google Workspace admin accounts — each with 10 domains and 40 email accounts. Used a reseller account rather than direct Google billing to save the client approximately 50% on monthly subscription costs.
Structure: 15 admin accounts × 10 domains × 4 mailboxes = 600 email accounts. Accounts split across 2 names for 2 separate client projects with shared inbox forwarding to 2 master inboxes.
3
DNS & Technical Records
Manually configured SPF, DKIM, DMARC, Custom Tracking Domain and domain redirections for every single domain. Each record verified individually for correct format and functionality before moving to the next domain.
No shortcuts: Every DNS record checked manually. A single misconfigured DMARC policy can blacklist an entire workspace. At 150 domains, there was no room for guesswork.
4
Instantly.ai Connection & Warmup
Connected all 600 accounts via OAuth (not App Password) for maximum connection stability and less disconnection risk. Set up warmup protocol: 25 maximum warmup limit, increasing by 1 per day for slow, natural warmup. Cold email sending started at 5 emails/day per account, increasing by 5 each week up to 25 by week 5.
Capacity: At full ramp (50 emails/day max per account), 600 accounts = 30,000 emails/day = 300,000 emails/month capacity. Achieved 80%+ open rates from the first campaigns launched.
5
Reply Management Setup
Configured 2 master inboxes with 299 accounts forwarded to each, keeping reply management centralised and efficient. This allowed the client's team to manage thousands of daily replies without needing to check hundreds of individual inboxes.
Capacity Built

What This Infrastructure Can Actually Send

600-Account Setup — Monthly Sending Capacity
600Email accounts
×25Max emails/day per account
×20Days per month
300,000 Maximum monthly email capacity (at full ramp) · Operational at 300K/month during warmup phase
600

Accounts — project 1

1,000

Accounts — project 2

2,000

Accounts — project 3

100%

Health score across all

Key Takeaways

Lessons From Setting Up 600 Email Accounts

Speed and quality are not opposites at scale — they're achieved through systematic process. Having a repeatable setup workflow for each layer (domains → workspace → DNS → warmup) is what allowed 600 accounts to be configured in under a week without errors.
Structure your workspace architecture before touching a single account. 15 admin accounts × 10 domains × 4 mailboxes is a deliberate choice — not a default. The structure determines how manageable the system is at scale.
OAuth over App Password every time at scale. More reliable connections, less disconnection risk, fewer interruptions to warmup continuity. At 600 accounts, even a 5% disconnection rate means 30 accounts losing warmup progress simultaneously.
Manual DNS verification is non-negotiable. Automated tools miss edge cases. At 150 domains, verifying each SPF, DKIM and DMARC record individually takes time — but a single misconfigured record on a shared workspace can damage the reputation of every account in that workspace.
Slow warmup protects the entire infrastructure investment. Starting at 5 emails/day and increasing by 5 per week feels slow — but it's what produces a 100% health score and 80%+ open rates on launch day. Rushing warmup burns the domains you just spent days configuring.

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