GTM stack
A GTM stack is the full set of tools a team runs to source, enrich, verify, and deliver outbound, plus the labor that wires them together, not just the tool with the biggest line item on the bill.
A GTM stack only does four jobs, no matter how many logos are duct-taped onto it. Sourcing finds the right accounts and contacts. Enrichment fills in the fields needed to reach and personalize to them. Verification confirms the contact info is real before anything sends. Delivery gets the message out and reports what happened. Every tool in the stack is doing one of those four jobs, and if a team can't say which one a given tool handles, that's the first sign it's dead weight.
Delivery is really three jobs wearing one name
Sourcing, enrichment, and verification map to one layer each. Delivery doesn't split that cleanly. Getting a message out and tracking what happened to it is one job. Holding the pipeline of record is a second. Watching whether the sending domain's reputation is still healthy is a third, and it runs on its own clock, not per send. In most real stacks, those three sit in three different tools, which means four jobs actually spread across six layers once delivery gets unbundled.
The cost most teams never price
Every published breakdown of what a GTM stack costs treats the tool bill as the whole number. It isn't. There's a fourth cost layer sitting on top of data, sending infrastructure, and deliverability monitoring: orchestration and labor, the person who designs the waterfall, decides what the routing logic should do, and rebuilds it when a vendor changes an API. Nobody sells that layer, which is exactly why it's the one every vendor comparison leaves out of the total.
In practice
The redundancy pattern shows up the same way in almost every stack: two tools with materially overlapping coverage, bought 'just in case' one of them comes up short. It usually starts as a trial nobody canceled. Six months later, a team is paying two subscriptions to solve the same coverage gap a single properly sequenced waterfall would have closed.
What people get wrong
People price a GTM stack by adding up subscription costs and stop there, missing the labor layer that's often the biggest line item once it's actually counted. The other common mistake is treating stack size as a proxy for capability. A smaller stack with clear ownership per layer beats a larger stack where several tools quietly do the same job twice.
