Every B2B integration page says "connect in minutes". Almost none of them tell you the connection requires a plan tier that costs 4× your current one.
So I spent the last few weeks auditing the official pricing pages and developer docs of 20 popular B2B tools, and built StackMatrix — a free, open index of what integrations actually cost: https://stackcostmatrix.com
What each of the 55 pair pages includes
- An interactive True Cost of Ownership calculator (team-size slider, required-tier toggle, "I already pay for both apps" incremental mode)
- The hidden cost trap: the exact tier gate, API add-on, or webhook paywall behind the "free integration" claim
- A spec matrix (native vs API-only, sync direction, webhooks at the required tier)
- Native vs middleware (Zapier/Make) total cost, compared honestly
Deep dives
- HubSpot ecosystem cost matrix: https://stackcostmatrix.com/hubspot-integrations-cost/
- Salesforce ecosystem cost matrix: https://stackcostmatrix.com/salesforce-integrations-cost/
- CRM integration pricing guide (native vs Zapier/Make across CRMs): https://stackcostmatrix.com/crm-integration-pricing-guide/
Calculators worth trying
- HubSpot + Slack — the $20/seat trap hiding behind a "free" integration: https://stackcostmatrix.com/stack/hubspot-and-slack/
- Salesforce + Stripe — including the $25/user API add-on nobody mentions: https://stackcostmatrix.com/stack/salesforce-and-stripe/
- Pipedrive + Xero: https://stackcostmatrix.com/stack/pipedrive-and-xero/
Open by default
The dataset is public and source-linked (every figure traces to an official vendor pricing page or developer doc): https://github.com/rakeshrkrk56-sketch/stackmatrix
Feedback welcome — especially corrections. Every price is re-verified against live vendor docs, and mismatches get flagged, never silently rewritten.
Top comments (1)
Pricing-tier gotchas are the hidden cost nobody documents, good idea. We make Preetest, an AI website-testing platform. If you would like a free full scan of stackcostmatrix.com (broken links across all those guide pages, mobile layout, accessibility, security headers, performance), just say yes here and we will send you the report. We do not scan without the owner's permission. In return we would ask only for an honest review of the result, even a negative one.