Vercel Speed Audit Skill

---

name: vercel-speed-audit

description: Optimize Vercel build and deploy speed — audit checklist for new and existing projects.

---

# Vercel Speed Audit Skill

Optimize Vercel build and deploy speed for any project. Run as a checklist when starting new projects or auditing existing ones.

When to Use

Triage First (Don't Blindly Run All 10)

Before running the full checklist, **measure and assess**:

# 1. Check current build times
cd <project> && npx vercel ls --limit 5

# 2. Check team/plan tier
npx vercel team ls

**Decision tree:**

| Build Time | Action |

|-----------|--------|

| **< 20s** | Only do items 0, 1, 3-5, 10. Skip GitHub Actions (#8), skip barrel file audit (#6) unless codebase is large. |

| **20-60s** | Do items 0-7, 10. GitHub Actions (#8) is optional. |

| **60s+** | Do everything. GitHub Actions (#8) becomes high-value. |

**Auth-gated app?** (All pages behind login)

→ **Skip ISR (#9)** entirely. ISR caches one response for all users — incompatible with per-user content.

**Framework:**

→ SvelteKit: Also read `docs/sveltekit.md` — includes adapter-vercel switch, prerendering, $env tips.

→ Next.js/Nuxt/Other: `docs/general.md` covers framework-agnostic items.

Checklist (Ordered by Impact)

| # | Optimization | Impact | CLI-checkable? | Plan Required |

|---|-------------|--------|:-:|:-:|

| **0** | **Use explicit adapter** (e.g., `adapter-vercel` not `adapter-auto`) | Faster, no detection overhead | ✅ Check config | Any |

| **1** | **Turbo Build Machines** | 50-70% faster builds | ❌ Dashboard only | Pro+ |

| **2** | **On-Demand Concurrent Builds** | Eliminates deploy queue | ❌ Dashboard only | Pro+ |

| **3** | **Prerender Static Pages** | Fewer functions, faster TTFB | ✅ Audit code | Any |

| **4** | **Ignored Build Step** | Skip irrelevant builds | ✅ Check vercel.json | Any |

| **5** | **Prioritize Production Builds** | Prod deploys go first | ❌ Dashboard only | Pro+ |

| **6** | **Eliminate Barrel Files** | 10-30% build speedup | ✅ Audit code | Any |

| **7** | **Audit & Trim Dependencies** | Faster install + bundle | ✅ Run depcheck | Any |

| **8** | **GitHub Actions + `--prebuilt`** | Full cache control, skip Vercel build | ✅ Add workflow | Any |

| **9** | **ISR for Dynamic Pages** | Fewer cold starts | ✅ Audit routes | Any |

| **10** | **Instant Rollback** | Zero-downtime recovery | ✅ `vercel rollback` | Hobby: last only; Pro+: any |

**Pro plan items (#1, #2, #5):** If not on Pro, check team plan first. These are the highest-impact free wins on Pro.

Dashboard Links (Can't Check via CLI)

For a team called `<team-slug>`:

Docs

Lessons Learned

Real-world findings from running all 10 checks on a SvelteKit project with 16-18s builds:

1. **Half the checklist was overkill** — builds were already fast. Triage step now prevents wasted effort.

2. **ISR is irrelevant for auth-gated apps** — every page served per-user content. Added decision tree.

3. **`adapter-auto` → `adapter-vercel` was a missed win** — not in original 10 but came up in dep audit. Now item #0.

4. **Dashboard-only settings are the highest-impact items** (Turbo, concurrent, priority) but can't be verified via CLI. Added direct links.

5. **GitHub Actions + prebuilt only worth it at 60s+** — for fast builds, the Vercel Git integration is simpler and equally fast.

6. **The dep audit found the project was already lean** (11 deps, 84MB node_modules, 472K client bundle). Only one unused dep (clsx).

7. **Team/plan tier gates most high-impact items** — checking plan should be step 1.

Quick Start

1. **Triage:** Measure build times + check plan tier

2. **Run applicable items** from the checklist based on decision tree

3. If SvelteKit, also review `docs/sveltekit.md`

4. Track findings in a report file (e.g., `vercel-speed-report.md`)

5. For complex CI needs, follow `docs/github-actions-prebuilt.md`