Google designed Workspace to help companies collaborate internally. Email became a feature, not the product. When you send cold emails through Google Workspace, you face three structural problems:

• Filtering algorithms treat bulk sending as threats: Google built their infrastructure to protect Gmail users from unwanted messages. Their systems interpret volume as spam risk even for legitimate B2B outreach.

• No native warm-up features: Google explicitly prohibits automated warm-up tools in their Acceptable Use Policy, restricting methods that artificially inflate delivery metrics.

• Corporate architecture conflicts with outbound needs: You need to send volume to generate meetings, but the platform penalizes the exact behavior cold email requires.

Shared IP pools create "neighbor noise"

Here's the technical reality most agencies miss: Google Workspace routes your emails through massive shared IP pools. Your sending reputation depends not just on your behavior, but on every other sender using those same IP ranges.

Think of it like a carpool lane where you're affected by other drivers. When someone in your IP neighborhood starts sending spam or experiences high complaint rates, it negatively affects your deliverability. One bad actor triggers an entire range getting flagged, and your legitimate campaigns get caught in the crossfire.

This "neighborhood effect" explains those mysterious deliverability drops. Your campaigns haven't changed, but someone else's behavior contaminated your shared infrastructure. ISPs treat emails from flagged IPs with suspicion, routing them to spam folders or rejecting them entirely.

For a detailed breakdown of how this works, watch our video on Dedicated IP vs Shared IP Pools for Cold Email. The visual comparison makes the reputation isolation concept immediately clear.

The "Outbound Gateway" bottleneck

Some agencies try to work around Google's limitations by configuring Outbound Gateways. These gateways process outgoing messages before they reach recipients, theoretically giving you more control over deliverability.

The reality is more complicated. Google's Outbound Gateway documentation requires complex configuration that most agencies fail to implement correctly:

1. SPF record modifications: Your SPF record must include both Google Workspace mail servers and the outbound gateway

2. Routing rules: You need to create routing rules in Google Admin console for every domain

3. IP whitelisting: Your gateway must only accept email from Google's IP addresses to prevent becoming an open relay

4. Authentication alignment: DKIM and DMARC records require reconfiguration to match the new sending path

Miss any step, and your emails fail authentication checks. The technical complexity creates more problems than it solves for most agency teams.

Gmail's 2025 bulk sender updates

Google tightened the screws on bulk senders starting February 2024, with intensified enforcement announced in November 2025. Anyone sending more than 5,000 messages per day to Gmail accounts must now meet strict requirements:

• Full authentication: SPF, DKIM, and DMARC records properly configured on every sending domain

• Spam rate threshold: Keep reported spam rates below 0.30% in Postmaster Tools

• One-click unsubscribe: Marketing messages must include visible unsubscribe links

The permanent classification trap: once you exceed 5,000 emails in a 24-hour period even once, Google permanently classifies you as a bulk sender. Non-compliant messages face "temporary and permanent rejections." For agencies managing multiple client campaigns, hitting this threshold happens faster than you'd expect.

The Ultimate Cold Email Infrastructure Guide for 2025 covers how these requirements affect infrastructure decisions and what you need to prepare for.