What are the ways to reduce dependencies in a fast website infrastructure?

Short answer: The rule of fast infrastructure is simple: the fastest byte is the one never loaded. Dependency reduction runs on two fronts: third-party scripts and your own bundle tree.

On the third-party side

• Build an inventory: assign an owner, a purpose, and a review date to every script in Tag Manager and templates; remove the orphans.
• Defer the rest: loading after visibility or interaction frees the main thread.
• Deduplicate measurement: never run two analytics or heatmap tools doing the same job.

In your own code

• Run a bundle analysis and question the heaviest dependencies: date, utility, and UI libraries often have built-in replacements.
• Fix imports that break tree-shaking, and prune polyfill weight against your target browser list.
• Subset fonts and serve them from your own domain.

Validate the effect through LCP and INP in Lighthouse and field data against the pre-change baseline; the gain varies by site and should never be reported without measurement.