Mayfield Fund
Mayfield Fund is an early-stage venture capital firm founded in 1969 and headquartered on Sand Hill Road in Menlo Park, California, with a presence in Mumbai, India. One of the oldest continuously active Silicon Valley firms, Mayfield describes itself as "people first, from inception" and reports that roughly 70% of its investments begin at company inception, positioning it as the first institutional investor for early-stage founders. The firm invests primarily at the Seed, Series A, and Series B stages across artificial intelligence, enterprise software, cloud and cybersecurity infrastructure, semiconductors, consumer and social commerce, and human and planetary health. Mayfield reports approximately $3B in assets under management (and states it has committed $3B to AI investments), has backed more than 550 companies over its history, and counts 120+ IPOs and 225+ M&A exits including Genentech, Lyft, HashiCorp, Poshmark, Marketo, Couchbase, SolarCity, Intuitive Surgical, and Compaq. In 2023 the firm raised $955M across two new funds dedicated to early-stage investing.
Mayfield Fund has 143 portfolio companies tracked on the APIs.io network, of which 49 (34%) publish APIs indexed here. The remaining 94 are tracked as profiles without a published API on the network.
Its highest-rated API providers on the network are Outreach, Big Panda, Couchbase, F5, Scrunch Ai.
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.
Strong 6 Solid coverage with minor gaps
Developing 14 Usable, with meaningful gaps to close
Thin 14 Limited public surface area
Emerging 11 Early or largely undocumented
Properties
Portfolio
Where the firm publishes its investments
Content
Blog, podcast, newsletter, and research
Firm
The firm itself
Cohort brief
Auto-generatedThe 103 portfolio companies with APIs in the catalog, backed by Mayfield Fund, 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 | 26.5 | 23.1 | +3.4 | 103 |
| Access Clarity | 28.6 | 26.4 | +2.2 | 103 |
| Contract Governance | 7.3 | 6.3 | +1 | 103 |
| Discoverability | 58.6 | 58.2 | +0.4 | 103 |
| Operational Transparency | 11.3 | 13.6 | -2.3 | 103 |
| Contract Quality | 15 | 17.6 | -2.6 | 103 |
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) | 19% | 15% | +4 |
| MCP server (first-party) | 19% | 12% | +7 |
| Agent Skills | 0% | 0% | 0 |
| OAuth scopes | 14% | 11% | +3 |
| Security | 95% | 98% | -3 |
| Arazzo workflows | 1% | 2% | -1 |
| Governance rules | 11% | 13% | -2 |
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 Outreach 76.9
- 2 BigPanda 71.8
- 3 F5 66.6
- 4 Scrunch AI 61.3
- 5 InfluxData 60.7
- 6 Cube 60.2
- 7 Couchbase 58.1
- 8 TrustRadius 58
- 9 Marketo 57.9
- 10 Basis 54.2
- 1 Scrunch AI 56.8
- 2 Outreach 54
- 3 BigPanda 52.8
- 4 F5 49.1
- 5 Alchemy 42
- 6 Revefi 41.9
- 7 Basis 40.8
- 8 Cube 36.4
- 9 Lyft 35.7
- 10 InfluxData 33.2
Coverage caveat. 89 of 103 scored members had under half their catalog-attributable points satisfied at all (catalog_earned / catalog_max < 0.5). They are INCLUDED in the mean above. A large share here means the cohort mean is partly a measurement of how far our enrichment reached, not only of how these providers publish.Generated from the catalog build of 3 October 2026, across 28834 providers, using the same computation served by the APIs.io cohort API. Briefs are published for rosters of 5 or more scored providers; below that a distribution is not meaningful.
Source (apis.yml)
Work with this as data
Every firm here is available over the APIs.io API and to AI agents over MCP.