Napkin Math

Napkin Math is a personalized AI food journal from Paper Star (a Y Combinator company, founded 2026 in San Francisco by Manuel Castro, Claire Nord, and Jynnie Tang). Marketed as "an AI nutrition coach in your pocket," it is a simple, beautiful food diary that helps people log meals and understand their eating habits over time. The product is a consumer mobile application rather than a developer platform: as of this profile Napkin Math publishes no public API, developer documentation, SDKs, OpenAPI, MCP server, or /.well-known discovery surface. This entry is maintained in the API Evangelist network as a company profile and enrichment lead; it will be upgraded to carry API artifacts if and when Napkin Math or Paper Star exposes a public API surface.

Napkin Math is profiled on the APIs.io network. Tagged areas include Company, Nutrition, Food Journal, Health, and Diet.

🌐 Visit website 📡 Source on GitHub
13.9/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-07-27 · rubric v0.5
0 APIs
CompanyNutritionFood JournalHealthDietArtificial IntelligenceConsumer ApplicationMobile ApplicationiOS

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 13.9/100 · minimal
Contract Quality 0.0 / 25
Developer Ergonomics 0.0 / 20
Commercial Clarity 4.2 / 20
Operational Transparency 0.0 / 13
Governance 0.0 / 12
Discoverability 6.8 / 10
Agent readiness — 0/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/napkin-math: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Security Posture 1

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Napkin Math Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Resources

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy

Company 1

The organization behind the API

Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: napkin-math
name: Napkin Math
description: 'Napkin Math is a personalized AI food journal from Paper Star (a Y Combinator company, founded 2026 in San Francisco
  by Manuel Castro, Claire Nord, and Jynnie Tang). Marketed as "an AI nutrition coach in your pocket," it is a simple, beautiful
  food diary that helps people log meals and understand their eating habits over time. The product is a consumer mobile application
  rather than a developer platform: as of this profile Napkin Math publishes no public API, developer documentation, SDKs,
  OpenAPI, MCP server, or /.well-known discovery surface. This entry is maintained in the API Evangelist network as a company
  profile and enrichment lead; it will be upgraded to carry API artifacts if and when Napkin Math or Paper Star exposes a
  public API surface.'
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://napkinmath.club/opengraph-image.png
url: https://raw.githubusercontent.com/api-evangelist/napkin-math/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
x-parent-company: Paper Star
x-tier: stub
x-tier-reason: consumer-app-no-api
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-20'
tags:
- Company
- Nutrition
- Food Journal
- Health
- Diet
- Artificial Intelligence
- Consumer Application
- Mobile Application
- iOS
common:
- url: https://napkinmath.club
  type: Website
- url: https://www.paperstar.cc/napkin-math/terms
  type: TermsOfService
- url: https://www.paperstar.cc/napkin-math/terms
  type: PrivacyPolicy
- url: security/napkin-math-domain-security.yml
  type: DomainSecurity
apis: []
x-enrichment:
  date: '2026-07-20'
  status: nochange
  artifacts_added: 0
  pass: local-v1
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io