Topograph

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#Why I built this

Ownership data across a VC portfolio is split between Carta (cap tables) and AngelList (deal records). Answering "what's our current ownership in company X after their Series B?" meant pulling multiple Carta reports and cross-referencing spreadsheets. I wanted a single dashboard that modelled ownership through every financing event across all funds.

#What it does

Topograph pulls live cap table data from Carta and AngelList, models ownership through each financing event, and computes current stakes and follow-on exposure across the full portfolio. A unified dashboard surfaces ownership percentages, cost basis, MOIC, and dilution history — all in one place.

#Data integration

#Carta API

Carta provides cap table data per company: share classes, outstanding shares, option pools, and conversion terms. Topograph pulls:

• Stakeholder positions — fund's shares by class, with vesting schedules and conversion rights
• Financing rounds — pre/post-money valuation, new shares issued, price per share
• Cap table snapshots — fully-diluted ownership at each round close

The API returns data per fund entity, so Topograph aggregates across Fund 1, 2, and 3 to compute total exposure per company.

#AngelList API

AngelList provides deal-level data that Carta doesn't: investment amount, deal terms (pro-rata rights, liquidation preferences), and syndicate co-investors. This fills in the financial picture that Carta's equity-focused view misses.

#Reconciliation

Carta and AngelList don't always agree — rounding differences, timing mismatches on round closes, and occasional data entry errors. Topograph runs a reconciliation step that flags discrepancies above a configurable threshold (default: 0.5% ownership difference) for manual review.

#Equity modelling

#Dilution waterfall

For each company, Topograph models the ownership waterfall:

1. Start with initial investment position (shares + cost basis)
2. Apply each subsequent financing round: new shares issued → dilution to existing holders
3. Factor in option pool expansions and convertible note conversions
4. Compute current fully-diluted ownership percentage

The model handles standard and weighted-average anti-dilution provisions, pay-to-play clauses, and participation rights on liquidation preferences.

#Portfolio metrics

Metric	Computation
MOIC	Current fair value ÷ total invested capital
IRR	Time-weighted return using investment dates and current valuation
Ownership %	Fully-diluted shares held ÷ total fully-diluted shares
Unrealised gain	(Current valuation × ownership %) - cost basis
Follow-on exposure	Pro-rata allocation needed to maintain ownership in next round

All metrics are computed per-company and aggregated per-fund, with a portfolio-wide roll-up.

#Quarterly snapshots

Topograph stores quarterly snapshots of all metrics, enabling trend analysis: MOIC over time, ownership drift, and valuation multiples. The snapshot diff view highlights which companies moved the most quarter-over-quarter — useful for LP reporting and internal reviews.

#Technical decisions

• Quarterly sync over real-time — cap table data changes at most a few times per year (financing rounds, option grants). A quarterly sync with manual trigger for round closes is sufficient. Real-time would add complexity for no practical benefit.
• Computed columns over pre-aggregated tables — ownership percentages and MOIC are computed on read, not stored. This means the dashboard always reflects the latest data model without migration headaches when the calculation logic changes.
• Server-side rendering for financial data — all portfolio data stays server-side. The client never receives raw ownership numbers or valuations — only the rendered dashboard. This is a security requirement for LP-sensitive data.

#Stack

Next.js 15, Carta API, AngelList API, Supabase PostgreSQL, Tailwind CSS, Vercel