Andreessen Horowitz
Andreessen Horowitz (a16z) is a Silicon Valley venture capital firm founded in July 2009 by Marc Andreessen and Ben Horowitz and headquartered in Menlo Park, California. The firm invests across the full lifecycle from seed to venture to growth-stage technology companies, deploying stage-based checks that range from roughly $1M-$5M into early application bets up to hundreds of millions of dollars into its largest AI positions. a16z organizes around dedicated practice areas: AI, American Dynamism, Bio + Healthcare, Consumer, Crypto, Enterprise, Fintech, Games, Infrastructure, plus specialty vehicles including the Cultural Leadership Fund, Perennial, and the Speedrun accelerator. With over $90B-$100B+ in assets under management as of early 2026 and a public portfolio of more than 1,000 companies, a16z is one of the largest and most influential venture firms in the world, known for its operator-led platform model and notable investments including Airbnb, Coinbase, GitHub, Figma, Stripe, Databricks, Anduril, and OpenAI.
Andreessen Horowitz has 1,100 portfolio companies tracked on the APIs.io network, of which 380 (35%) publish APIs indexed here. The remaining 717 are tracked as profiles without a published API on the network.
Its highest-rated API providers on the network are Stripe, OpenAI, ElevenLabs, Svix, Optimizely.
Portfolio on the Network
Portfolio companies that publish APIs indexed on APIs.io, grouped by their API Evangelist rating. Exemplar and Strong are expanded by default.
Exemplar 23 Complete, well-documented, and agent-ready
Strong 39 Solid coverage with minor gaps
Developing 122 Usable, with meaningful gaps to close
Thin 124 Limited public surface area
Emerging 63 Early or largely undocumented
Unrated 2 Not yet scored
Rest of Portfolio
3 further portfolio companies that don’t yet have a provider page on the network.
Scroll for all 3
Properties
Portfolio
Where the firm publishes its investments
Content
Blog, podcast, newsletter, and research
Firm
The firm itself
Cohort brief
Auto-generatedThe 747 portfolio companies with APIs in the catalog, backed by Andreessen Horowitz, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.
| Facet | This cohort | Catalog | Difference | Scored |
|---|---|---|---|---|
| Developer Ergonomics | 26.8 | 23.8 | +3 | 747 |
| Access Clarity | 28.6 | 27.2 | +1.4 | 747 |
| Operational Transparency | 15.6 | 14.4 | +1.2 | 747 |
| Discoverability | 62.1 | 61.5 | +0.6 | 747 |
| Contract Quality | 20.4 | 20.4 | 0 | 747 |
| Contract Governance | 6 | 6.6 | -0.6 | 747 |
A facet is averaged over the members that carry it, not over the whole cohort — the “Scored” column is that count. Averaging an absent facet as zero would score our own coverage gaps as the providers’ posture.
| Artifact | This cohort | Catalog | Difference |
|---|---|---|---|
| MCP server (any) | 11% | 11% | 0 |
| MCP server (first-party) | 14% | 13% | +1 |
| Agent Skills | 0% | 0% | 0 |
| OAuth scopes | 8% | 12% | -4 |
| Security | 89% | 96% | -7 |
| Arazzo workflows | 4% | 2% | +2 |
| Governance rules | 12% | 13% | -1 |
mcp_pct counts any mcp/ artifact including ones API Evangelist derived from the provider OpenAPI; mcp_first_party_pct counts only servers the provider publishes. Prefer the latter.
- 1 Stripe 87.9
- 2 OpenAI 82.9
- 3 ElevenLabs 82.3
- 4 Svix 80.4
- 5 Optimizely 78
- 6 Twilio 77.8
- 7 Mux 77.7
- 8 Ghost 77.2
- 9 GitHub 77.2
- 10 Doordash 75.8
Source (apis.yml)
Work with this as data
Every firm here is available over the APIs.io API and to AI agents over MCP.