Emailio website screenshot

Emailio

Emailio is a Y Combinator (Winter 2014) and Thiel Fellowship-backed startup building "email built for wellness" — a consumer email client for iPhone, iPad, and Mac that centers user wellbeing and mental health rather than traditional inbox-productivity metrics. Its pre-launch landing page describes inbox management, email batching, mood tracking, one-click unsubscribe, and Smart Rule Suggestions, with early access gated behind a waitlist. Founded by Martin Stoyanov and Teo Teodosiev with a roughly five-person team, Emailio sits at the intersection of the productivity and health & wellness categories. It was surfaced as a Y Combinator portfolio company and added to the API Evangelist network as a stub for enrichment; as of this pass it exposes a consumer product only — no public API, developer portal, documentation, or SDKs could be found.

Emailio is profiled on the APIs.io network. Tagged areas include Company, Email, Email Client, Productivity, and Health and Wellness.

Emailio’s developer surface includes signup flow and 2 more developer resources.

🌐 Visit website 📡 Source on GitHub
9.4/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-07-27 · rubric v0.5
AccessApproval
0 APIs
CompanyEmailEmail ClientProductivityHealth and WellnessConsumerY CombinatorThiel Fellowship

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-27 · rubric v0.5
Composite quality — 9.4/100 · minimal
Contract Quality 0.0 / 25
Developer Ergonomics 0.0 / 20
Commercial Clarity 2.6 / 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/emailio: 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.

Emailio Domain Security

TLSv1.2

SECURITY

Resources

Get Started 1

Portal, sign-up, and the first successful call

SignUp
SignUp

Access & Security 1

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity

Company 1

The organization behind the API

Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: emailio
accessModel:
  pricing: unknown
  onboarding: approval
  trial: false
  try_now: false
  public: false
  label: Requires approval
  confidence: medium
  source: []
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/emailio.png
name: Emailio
description: Emailio is a Y Combinator (Winter 2014) and Thiel Fellowship-backed startup building "email built for wellness"
  — a consumer email client for iPhone, iPad, and Mac that centers user wellbeing and mental health rather than traditional
  inbox-productivity metrics. Its pre-launch landing page describes inbox management, email batching, mood tracking, one-click
  unsubscribe, and Smart Rule Suggestions, with early access gated behind a waitlist. Founded by Martin Stoyanov and Teo Teodosiev
  with a roughly five-person team, Emailio sits at the intersection of the productivity and health & wellness categories.
  It was surfaced as a Y Combinator portfolio company and added to the API Evangelist network as a stub for enrichment; as
  of this pass it exposes a consumer product only — no public API, developer portal, documentation, or SDKs could be found.
url: https://raw.githubusercontent.com/api-evangelist/emailio/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- y-combinator
- thiel-fellowship
x-yc-batch: W2014
x-founders:
- Martin Stoyanov
- Teo Teodosiev
x-status: no-public-api
x-tier: stub
x-tier-reason: portfolio-lead
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-19'
tags:
- Company
- Email
- Email Client
- Productivity
- Health and Wellness
- Consumer
- Y Combinator
- Thiel Fellowship
apis: []
common:
- type: DomainSecurity
  url: security/emailio-domain-security.yml
- type: Website
  url: https://www.emailio.com
  name: Emailio Website
- type: SignUp
  url: https://www.emailio.com
  name: Request Access
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
x-enrichment:
  date: '2026-07-19'
  status: backfilled
  pass: local-v1
  note: backfilled from .gitignore signal + verified work evidence