mailfloss

mailfloss provides an automated email verification service that cleans email lists on autopilot, preventing bot sign‑ups, typos, and bounces. Founded to solve deliverability problems, it integrates with major ESPs, offers real‑time typo fixing, and supports teams of any size. The platform runs continuously, protecting sender reputation and reducing ad spend by ensuring only valid addresses remain in marketing lists.

mailfloss publishes 8 API contracts indexed on the APIs.io network, including Account API, Batch API, Integrations API, and 5 more. Tagged areas include Email Verification, Marketing, Software-as-a-Service, Automation, and Deliverability.

The mailfloss catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

mailfloss’ developer surface includes authentication, documentation, API reference, getting-started guide, support, engineering blog, pricing, and 29 more developer resources.

🌐 Visit website 📡 Profile data on GitHub

51.2/100 developing Agent 59/100 agent native Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

1 published contract

Email Verification Marketing Software-as-a-Service Automation Deliverability

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 51.2/100 · developing

Contract Quality 11.9 / 21

Developer Ergonomics 7.1 / 17

Access Clarity 9.2 / 17

Operational Transparency 4.7 / 11

Contract Governance 3.6 / 10

Discoverability 5.6 / 9

Regulatory Posture 4.0 / 15

Agent readiness — 59/100 · agent native

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 4 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 6 / 6

Protected Resource Metadata 5 / 5

Registration Without a Human 6 / 6

Agentic Commerce Well-Known Document 0 / 5

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks
Documented Reversibility +6 pts — a reversal operation in the contract, graded up when a window is documented too
Agent Skills +5 pts — skills artifact present, graded by who authored it
Agentic Commerce Well-Known Document +5 pts — a parsing /.well-known/ucp.json or acp.json declaring a version and at least one service, OR (0.27) a live x402 payment challenge from _data/x402-adoption.json — `self` when its endpoints are on the provider's own domain, `platform` when they are on a vendor's

2 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Developer Ergonomics scores 41.7 — up to +11.7 composite points
Contract Quality scores 56.1 — up to +11.0 composite points
Access Clarity scores 53.9 — up to +9.2 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from the provider profile at artifacts.apis.io/mailfloss/apis.yml: open an issue on github.com/api-evangelist/mailfloss to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Standards implemented 3

Standards this provider implements or carries. De facto ones are profiled and measured by the API Commons; formal ones come from the standards directory and are linked by the provider's own tags. The evidence column says how each claim was established — not that it was made.

OAuth 2.0 Protected Resource Metadata

measured — observed by APIs.io (verified)

Dynamic Client Registration

measured — observed by APIs.io (published)

OpenAPI

measured — observed by APIs.io (published)

APIs 8

Individual APIs this provider publishes, each with its own machine-readable definition.

mailfloss Account API

Account info, credits, API key management

mailfloss Batch API

Asynchronous batch verification jobs

mailfloss Integrations API

ESP connections — connect, list, manage, and configure email-platform integrations (incl. per-connection keyword rules)

mailfloss Privacy API

Data privacy / erasure API

mailfloss Reports API

Verification usage analytics

mailfloss Team API

Organization members / seats

mailfloss Verification API

Single-email verification endpoints

mailfloss Webhooks API

Webhook subscriptions — event notifications POSTed to your endpoints

Scroll for all 8

mailfloss API pricing

Prices published by mailfloss, read 2026-11-03 from mailfloss.com/pricing/.

Plan	Price
Pro	$209/ month
Business	$59/ month
Lite	$29/ month

Plan details, limits and sources →

Rate limits

mailfloss API (current): 10,000 requests per minute
mailfloss Legacy API (email verification): 50 requests per minute

Rate-limit details →

Pricing Plans 1

Published pricing tiers and plan structures.

Mailfloss Plans Pricing

3 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Mailfloss Rate Limits

2 limits

RATE LIMITS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Mailfloss Context

1 classes · 1 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

mailfloss API Rules

62 rules · 55 errors 4 warnings 3 info

SPECTRAL

Security Posture 3

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

Mailfloss Authentication

2 schemes

SECURITY

Mailfloss Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Mailfloss Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Mailfloss Agentic Access

33 operations · 14 acting

AGENTIC

Resources

Get Started 3

Portal, sign-up, and the first successful call

Login

DeveloperPortal

DeveloperPortal

GettingStarted

GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

LLMsTxt

LLMsTxt

WellKnown

WellKnown

Design & Contract 9

Pagination, idempotency, versioning, errors, and events

Spectral

JSONLD

Vocabulary

DataModel

Idempotency

Conventions

Lifecycle

ErrorCatalog

Conformance

Scroll for all 9

Build 3

SDKs, sample code, and the tooling you integrate with

Packages

Packages

SDKs

SDKs

GitHubOrganization

GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

Security

Security

Authentication

Authentication

SecurityTxt

SecurityTxt

VulnerabilityDisclosure

VulnerabilityDisclosure

DomainSecurity

DomainSecurity

Operate 3

Status, limits, changes, and where to get help

RateLimits

RateLimits

Deprecation

Deprecation

Support

Support

Commercial 4

Pricing, plans, and the legal terms of use

Plans

Pricing

TermsOfService

PrivacyPolicy

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Hosts

Hosts

Vendors

Vendors

Source (apis.yml)

aid: mailfloss
name: mailfloss
accessModel:
  pricing: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: high
  probe_state: gated
  source:
  - plans
  - authentication
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://mailfloss.com/og-default.png
description: mailfloss provides an automated email verification service that cleans email lists on autopilot, preventing bot
  sign‑ups, typos, and bounces. Founded to solve deliverability problems, it integrates with major ESPs, offers real‑time
  typo fixing, and supports teams of any size. The platform runs continuously, protecting sender reputation and reducing ad
  spend by ensuring only valid addresses remain in marketing lists.
url: https://artifacts.apis.io/mailfloss/apis.yml
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-11-03 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-11-03'
modified: '2026-11-03'
tags:
- Email Verification
- Marketing
- Software-as-a-Service
- Automation
- Deliverability
tags_raw:
- Email Verification
- Marketing
- SaaS
- Automation
- Deliverability
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/mailfloss-agentic-access.yml
- type: RateLimits
  url: rate-limits/mailfloss-rate-limits.yml
- type: Plans
  url: plans/mailfloss-plans-pricing.yml
- type: Spectral
  url: rules/mailfloss-rules.yml
- type: JSONLD
  url: json-ld/mailfloss-context.jsonld
- type: Vocabulary
  url: vocabulary/mailfloss-vocabulary.yml
- type: DataModel
  url: data-model/mailfloss-data-model.yml
- type: Idempotency
  url: conventions/mailfloss-conventions.yml
- type: Conventions
  url: conventions/mailfloss-conventions.yml
- type: Security
  url: security/mailfloss-vulnerability-disclosure.yml
- type: Authentication
  url: authentication/mailfloss-authentication.yml
- type: Deprecation
  url: lifecycle/mailfloss-lifecycle.yml
- type: Lifecycle
  url: lifecycle/mailfloss-lifecycle.yml
- type: ErrorCatalog
  url: errors/mailfloss-problem-types.yml
- type: Conformance
  url: conformance/mailfloss-conformance.yml
- type: LLMsTxt
  url: llms/mailfloss-llms.txt
- type: SecurityTxt
  url: well-known/mailfloss-security.txt
- type: WellKnown
  url: well-known/mailfloss-well-known.yml
- type: Hosts
  url: hosts/mailfloss-hosts.yml
- type: Vendors
  url: vendors/mailfloss-vendors.yml
- type: Packages
  url: packages/mailfloss-packages.yml
- type: SDKs
  url: https://www.npmjs.com/package/@mailfloss/sdk
- type: Login
  url: https://app.mailfloss.com/login
- type: DeveloperPortal
  url: https://api.mailfloss.com\
- type: GitHubOrganization
  url: https://github.com/mailfloss
- type: VulnerabilityDisclosure
  url: security/mailfloss-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/mailfloss-domain-security.yml
- type: Website
  url: https://mailfloss.com/
- type: Documentation
  url: https://developers.mailfloss.com
- type: APIReference
  url: https://developers.mailfloss.com
- type: GettingStarted
  url: https://developers.mailfloss.com/quickstart
- type: Support
  url: https://status.mailfloss.com
- type: Blog
  url: https://mailfloss.com/blog
- type: Pricing
  url: https://mailfloss.com/pricing
- type: TermsOfService
  url: https://mailfloss.com/terms
- type: PrivacyPolicy
  url: https://mailfloss.com/privacy
apis:
- aid: mailfloss:mailfloss-account-api
  name: mailfloss Account API
  description: Account info, credits, API key management
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Account
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-account-api-openapi.yml
- aid: mailfloss:mailfloss-batch-api
  name: mailfloss Batch API
  description: Asynchronous batch verification jobs
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Batch
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-batch-api-openapi.yml
- aid: mailfloss:mailfloss-integrations-api
  name: mailfloss Integrations API
  description: ESP connections — connect, list, manage, and configure email-platform integrations (incl. per-connection keyword
    rules)
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Integration
  tags_raw:
  - Integrations
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-integrations-api-openapi.yml
- aid: mailfloss:mailfloss-privacy-api
  name: mailfloss Privacy API
  description: Data privacy / erasure API
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Privacy
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-privacy-api-openapi.yml
- aid: mailfloss:mailfloss-reports-api
  name: mailfloss Reports API
  description: Verification usage analytics
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Reports
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-reports-api-openapi.yml
- aid: mailfloss:mailfloss-team-api
  name: mailfloss Team API
  description: Organization members / seats
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Team
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-team-api-openapi.yml
- aid: mailfloss:mailfloss-verification-api
  name: mailfloss Verification API
  description: Single-email verification endpoints
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Verification
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-verification-api-openapi.yml
- aid: mailfloss:mailfloss-webhooks-api
  name: mailfloss Webhooks API
  description: Webhook subscriptions — event notifications POSTed to your endpoints
  humanURL: https://mailfloss.com/email-verification-api/
  baseURL: https://api.mailfloss.com
  tags:
  - Webhook
  tags_raw:
  - Webhooks
  properties:
  - type: OpenAPI
    url: openapi/mailfloss-webhooks-api-openapi.yml
x-submission-notes: apis.json at mailfloss.com/apis.json
x-submission-probe: docs 200 on 2026-11-03
x-submitted-by: hello@mailfloss.com (apis.io/add, 2026-11-03)
x-coverage:
  state: gated
  reason: partner-login
  method: derived
  generated: '2026-11-03'
  generator: derive-coverage.py (pre-flight evidence)
  detail: the company serves an API surface but requires credentials before any description of it can be read
  evidence:
  - url: https://developers.mailfloss.com/mcp
    status: null
  - url: https://api.mailfloss.com/swagger.json
    status: null
  - url: https://api.mailfloss.com/mcp
    status: 401
  - url: https://mailfloss.com/
    status: 200
x-enrichment:
  date: '2026-11-03'
  status: enriched
  artifacts_added: 29
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

mailfloss API — frequently asked questions

Does mailfloss have an API?

Yes. APIs.io lists 8 APIs from mailfloss, including mailfloss Account API, mailfloss Batch API and mailfloss Integrations API, and 5 more.

Is there an OpenAPI specification for the mailfloss API?

Yes. APIs.io indexes 8 OpenAPI specifications for mailfloss, each linked for download from this page.

How do I authenticate with the mailfloss API?

mailfloss documents its authentication (2 schemes). The details are profiled on APIs.io as Mailfloss Authentication.

How much does the mailfloss API cost?

mailfloss publishes its prices; its Pro plan is $209/ month as of 2026-11-03. APIs.io lists 3 pricing plans for mailfloss, with each plan's price, limits and inclusions under Pricing on this page.

Is the mailfloss API ready for AI agents?

mailfloss has a Kin Score of 51.2 out of 100 (developing) and an Agent Readiness score of 58.5 (agent-native), scored by API Evangelist on 2026-11-06.

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