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Comparison

OpenCap Stack vs Carta

OpenCap Stack and Carta both land on Depends.

OpenCap Stack

opencapstack.com

Depends

Confidence: Low

A reasonable free option for technical, pre-Series A founders who will self-host or accept an early-stage product.

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Carta

Depends

Confidence: Medium

Buy if you're a venture-backed startup or VC fund that needs the market-standard cap table and fund-admin suite.

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OpenCap Stack versus Carta
Compare	OpenCap Stack	Carta
Verdict	Depends	Depends
Best for	Pre-seed to Series A startups	Venture-backed startups with complex cap tables
Who it's not for	Non-technical founders wanting hands-off hosted service	Pre-seed startups with a simple cap table . use a spreadsheet
Privacy	No known public vulnerabilities found in the sources reviewed.^⁷	Carta runs a public trust center and bug bounty, but had a 2024 customer-data privacy breach that forced it to shut its trading platform.¹⁴
Support quality	No user support evidence found	Complaints on Software Advice and Trustpilot
Public sentiment	No independent third-party reviews or verbatim user quotes were found in the sources reviewed.¹¹	G2 ratings are solid but Reddit, Trustpilot, and Software Advice surface pricing, support, and trust complaints.¹²
Biggest gotcha	Hosted pricing not clearly published; free applies to self-hosting . verify before committing^⁹	2024 breach: customer data was misused to contact other customers' investors; trading platform shut down.¹⁴

Pick OpenCap Stack when

Pre-seed to Series A startups
Cost-sensitive founders avoiding Carta fees
Technical teams comfortable self-hosting
Accountants doing 409A reviews

When OpenCap Stack is not a fit

Non-technical founders wanting hands-off hosted service
Late-stage companies needing audited vendor SLAs
Teams requiring phone support and compliance guarantees
Buyers who need a mature product with real user reviews

Pick Carta when

Venture-backed startups with complex cap tables
VC funds needing fund administration
Companies running tender offers or IPO prep

When Carta is not a fit

Pre-seed startups with a simple cap table . use a spreadsheet
Budget-sensitive teams wanting flat, predictable pricing
Anyone unwilling to trust Carta with sensitive data post-breach
Teams expecting responsive, hands-on support

Sources

OpenCap Stack . Open Source Cap Table & Equity Managementopencapstack.com
official
Cap Table Management Software | Free, Open Sourceopencapstack.com
official
Earn as a 409A Reviewer . OpenCap Stack for Accountantsopencapstack.com
official
Open-Cap-Stack/opencap GitHub repositorygithub.com
official
Open Cap Stack GitHub organizationgithub.com
official
OpenCap Stack Overview . OCTA schema docsdocs.ainative.studio
official
OpenCap Stack security pageopencapstack.com
official
Carta vs Pulley vs OpenCap Stack comparison (vendor blog)opencapstack.com
review
Best Cap Table Software for Startups in 2026 (vendor blog)opencapstack.com
review
Ranveer Deshmukh . OpenCapStack MongoDB to ZeroDB migrationin.linkedin.com
news
Private Equity vs Venture Capital (third-party mention)ainative.ax
review
Carta Products | 296 Reviews on G2g2.com
review
Carta Equity Suite Pricing Overview . G2g2.com
review
Carta shuts trading platform after data privacy breach . FTft.com
news
VC world rocked by allegations against Carta . Fast Companyfastcompany.com
news
Carta pricing plans (+ hidden costs explained) . Spendflospendflo.com
review