From Two Repos to One: Migrating bfpinvest.com to a Monorepo

How we restructured two separate GitHub repositories into a single monorepo, reconfigured three Vercel projects, and set up path-scoped build triggers.

We recently consolidated two GitHub repositories — lockezhou18/bfp (the Next.js marketing site) and lockezhou18/bfp-invest (company ops and tooling) — into a single monorepo. Notes on what we did and what we ran into.

Why a Monorepo?

The split made sense early on. The website was a standalone Next.js project; the ops tooling (Prometheus exporter, Vercel DNS manager, credential aggregator) lived separately. But as the project grew, the friction mounted:

PRs that spanned both repos required coordination across two repositories
No shared git history made it hard to trace “what changed around the same time as X”
Vercel was pointing at lockezhou18/bfp — a repo that had nothing to do with the company’s operational layer

The tipping point was adding a backend: we wanted Supabase, API routes, and eventually authenticated tooling. That needed a shared workspace, not two separate codebases.

The Structure

The new layout:

bfp-invest/
├── web/          # Next.js 15 — www.bfpinvest.com
├── blog/         # Astro — blog.bfpinvest.com (this site)
├── services/     # Future Python workers
├── tools/        # bfp_auth.py, vercel_dns.py, exporter.py
├── ops/          # company-profile.md, DNS runbooks
└── tests/e2e/    # Future Playwright tests

web/ and blog/ are fully independent deployables — different frameworks, different package.json files, different Vercel projects. The monorepo doesn’t force them to share dependencies; it just gives them a shared git history and a single place to land PRs.

Pulling in the Old Repo

We used git subtree to bring lockezhou18/bfp history into bfp-invest/web/ without losing commits:

# In bfp-invest/
git remote add bfp https://github.com/lockezhou18/bfp.git
git fetch bfp
git merge -s ours --no-commit --allow-unrelated-histories bfp/main
git read-tree --prefix=web/ -u bfp/main
git commit -m "refactor: pull lockezhou18/bfp into web/ subtree"

This replays the full history from the old repo into the web/ subdirectory. The old repo now lives at lockezhou18/bfp-archive.

Reconfiguring Vercel

The tricky part. Three projects (bfp, bfp-mvp, bfp-work) all pointed at lockezhou18/bfp. We needed to:

Reconnect each project to lockezhou18/bfp-invest
Set rootDirectory: web so Vercel builds from the right subdirectory
Add an ignored build step so pushes to tools/ or ops/ don’t trigger a deploy

The Vercel API doesn’t let you update link via PATCH /v9/projects/{id} — that returns a bad_request: should NOT have additional property link error. You have to disconnect first:

# Disconnect from old repo
DELETE /v9/projects/{id}/link

# Reconnect to new repo
POST /v9/projects/{id}/link
{
  "type": "github",
  "repo": "lockezhou18/bfp-invest",
  "repoId": 1217681571
}

Then set rootDirectory and commandForIgnoringBuildStep via a separate PATCH:

PATCH /v9/projects/{id}
{
  "rootDirectory": "web",
  "commandForIgnoringBuildStep": "git diff HEAD^ HEAD --quiet -- web/"
}

The counterintuitive part: git diff --quiet exits 0 when there are no changes — which Vercel treats as “skip the build.” So a push that only modifies tools/ will make git diff HEAD^ HEAD --quiet -- web/ exit 0 (no web/ changes) and Vercel skips. A push that touches web/ exits 1 (changes exist) and Vercel builds. This is exactly what you want, but the logic feels backwards at first.

We also took the opportunity to clean up: bfp-mvp (a stale project with messy deploy history from the old repo) was deleted and recreated as bfp-staging. bfp-work was deleted entirely.

What Vercel Shows as “CANCELED”

One thing that confused us: deploys that were skipped by the ignored build step show up as CANCELED in the Vercel API — not SKIPPED. This is expected behavior. Don’t panic when you see it.

Result

One repo, one PR flow, shared git history
www.bfpinvest.com and blog.bfpinvest.com both deploy from bfp-invest with path-scoped triggers
The old lockezhou18/bfp repo is preserved at lockezhou18/bfp-archive for reference
TypeScript build error in the evaluate page (pre-existing, uncovered by the migration) was caught and fixed as part of the process

The monorepo isn’t magic — it’s just a better container for work that belongs together.