Return Path

Return Path is an email-deliverability and inbox-intelligence brand that pioneered sender reputation, inbox-placement monitoring, and email fraud protection for marketers and email senders. Founded in 1999 and backed by Sapphire Ventures and Union Square Ventures, Return Path was acquired by Validity in 2019 and now ships as the Validity Everest email-success platform; returnpath.com 301-redirects to validity.com. The platform draws on signals from billions of global mailboxes to measure inbox placement, sender reputation, and deliverability across major mailbox providers. The Return Path product line's surviving API surface is the Everest API at api.everest.validity.com — 170 published operations across inbox placement, sender reputation and Sender Score, blocklist and spam-trap monitoring, DMARC infrastructure reporting, engagement analytics, list validation and certification. Validity publishes no OpenAPI, but it does publish a complete public Postman collection at developer.everest.validity.com, which is the machine-readable contract this profile is built from.

Return Path publishes 11 APIs on the APIs.io network, including Account Services API, Apps & Integrations API, Certification API, and 8 more. Tagged areas include Company, MarTech, Email, Email Deliverability, and Email Marketing.

The Return Path catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Return Path’s developer surface includes engineering blog, support, documentation, API reference, authentication, and 29 more developer resources.

🌐 Visit website 📡 Source on GitHub

42.6/100 developing ▬ flat Agent 34/100 agent ready saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessEnterpriseApproval

11 APIs

Company MarTech Email Email Deliverability Email MarketingSender ReputationInbox PlacementDeliverability DMARC Email Authentication Email Validation Analytics

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 42.6/100 · developing

Contract Quality 5.7 / 23

Developer Ergonomics 9.3 / 18

Access Clarity 9.0 / 18

Operational Transparency 4.6 / 12

Contract Governance 0.5 / 11

Discoverability 7.3 / 9

Create-or-Update Ergonomics 2.8 / 10

Agent readiness — 34/100 · agent ready

Machine-Readable Contract 18 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

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 github.com/api-evangelist/return-path: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 11

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

Return Path Account Services API

The Account Services API from Return Path — 13 operation(s) for account services.

Return Path Apps & Integrations API

The Apps & Integrations API from Return Path — 12 operation(s) for apps & integrations.

Return Path Certification API

The Certification API from Return Path — 2 operation(s) for certification.

Return Path Competitive Intel API

The Competitive Intel API from Return Path — 7 operation(s) for competitive intel.

Return Path Engagement API

The Engagement API from Return Path — 35 operation(s) for engagement.

Return Path Inbox Placement API

The Inbox Placement API from Return Path — 17 operation(s) for inbox placement.

Return Path Infrastructure (DMARC) API

The Infrastructure (DMARC) API from Return Path — 10 operation(s) for infrastructure (dmarc).

Return Path Legacy API (1.0) API

The Legacy API (1.0) API from Return Path — 6 operation(s) for legacy api (1.0).

Return Path List Validation API

The List Validation API from Return Path — 6 operation(s) for list validation.

Return Path Reputation API

The Reputation API from Return Path — 18 operation(s) for reputation.

Return Path View Time Optimization API

The View Time Optimization API from Return Path — 4 operation(s) for view time optimization.

Scroll for all 11

Pricing Plans 1

Published pricing tiers and plan structures.

Return Path Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Return Path Rate Limits

1 limits

RATE LIMITS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

Return Path Webhooks

ASYNCAPI

Security Posture 4

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

Return Path Authentication

apiKey · 1 scheme

SECURITY

Return Path Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Return Path Vulnerability Disclosure

Hackerone · contact published

SECURITY

Return Path Trust Center

SOC 2 Type 2, ISO/IEC 27001, ISO/IEC 27701, GDPR, CCPA, EU-US Data Privacy Framework, Microsoft SSPA, Standard Contractual Clauses

SECURITY

Resources

Get Started 2

Portal, sign-up, and the first successful call

DeveloperPortal

DeveloperPortal

Login

Documentation 2

Reference material describing how the API behaves

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 2

MCP servers, agent skills, and machine-readable catalogs

AgentSkill

AgentSkill

LLMsTxt

LLMsTxt

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

Webhooks

DataModel

Conformance

Build 2

SDKs, sample code, and the tooling you integrate with

Postman

Postman

Packages

Packages

Access & Security 9

Authentication, authorization, and security posture

TrustCenter

Compliance

Security

TrustCenter

Compliance

VulnerabilityDisclosure

VulnerabilityDisclosure

Security

Security

DomainSecurity

DomainSecurity

Authentication

Authentication

Scroll for all 9

Operate 4

Status, limits, changes, and where to get help

Support

HelpCenter

Community

RateLimits

Commercial 3

Pricing, plans, and the legal terms of use

PrivacyPolicy

PrivacyPolicy

TermsOfService

TermsOfService

Plans

Plans

Company 2

The organization behind the API

Website

Website

Blog

Blog

Other 2

Properties that don't map to a standard resource type

Overlay

Overlay

Product

Product

Source (apis.yml)

aid: return-path
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: enterprise
  onboarding: approval
  trial: false
  try_now: false
  public: false
  label: Enterprise, contact sales
  confidence: medium
  source:
  - https://www.validity.com/pricing/
  - https://developer.everest.validity.com/
  - url: https://www.returnpath.com/
    status: 301
    note: declared website redirects to https://www.validity.com/capabilities/engage-inbox-placement-and-deliverability/ —
      a different registrable domain (returnpath.com -> validity.com), possible rename or acquisition (probed 2026-09-03,
      roadmap#169)
  generated: '2026-08-13'
  method: searched
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/return-path.png
name: Return Path
description: Return Path is an email-deliverability and inbox-intelligence brand that pioneered sender reputation, inbox-placement
  monitoring, and email fraud protection for marketers and email senders. Founded in 1999 and backed by Sapphire Ventures
  and Union Square Ventures, Return Path was acquired by Validity in 2019 and now ships as the Validity Everest email-success
  platform; returnpath.com 301-redirects to validity.com. The platform draws on signals from billions of global mailboxes
  to measure inbox placement, sender reputation, and deliverability across major mailbox providers. The Return Path product
  line's surviving API surface is the Everest API at api.everest.validity.com — 170 published operations across inbox placement,
  sender reputation and Sender Score, blocklist and spam-trap monitoring, DMARC infrastructure reporting, engagement analytics,
  list validation and certification. Validity publishes no OpenAPI, but it does publish a complete public Postman collection
  at developer.everest.validity.com, which is the machine-readable contract this profile is built from.
url: https://raw.githubusercontent.com/api-evangelist/return-path/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- sapphire-ventures
- union-square-ventures
x-tier: profiled
x-tier-reason: published-api-surface
specificationVersion: '0.23'
created: '2026-07-17'
modified: '2026-08-13'
tags:
- Company
- MarTech
- Email
- Email Deliverability
- Email Marketing
- Sender Reputation
- Inbox Placement
- Deliverability
- DMARC
- Email Authentication
- Email Validation
- Analytics
tags_raw:
- Company
- Martech
- Email
- Email Deliverability
- Email Marketing
- Sender Reputation
- Inbox Placement
- Deliverability
- DMARC
- Email Authentication
- Email Validation
- Analytics
apis:
- aid: return-path:return-path-account-services-api
  name: Return Path Account Services API
  description: The Account Services API from Return Path — 13 operation(s) for account services.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Account Services
  properties:
  - type: OpenAPI
    url: openapi/return-path-account-services-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-apps-integrations-api
  name: Return Path Apps & Integrations API
  description: The Apps & Integrations API from Return Path — 12 operation(s) for apps & integrations.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Apps & Integrations
  properties:
  - type: OpenAPI
    url: openapi/return-path-apps-integrations-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-certification-api
  name: Return Path Certification API
  description: The Certification API from Return Path — 2 operation(s) for certification.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Certification
  properties:
  - type: OpenAPI
    url: openapi/return-path-certification-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-competitive-intel-api
  name: Return Path Competitive Intel API
  description: The Competitive Intel API from Return Path — 7 operation(s) for competitive intel.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Competitive Intel
  properties:
  - type: OpenAPI
    url: openapi/return-path-competitive-intel-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-engagement-api
  name: Return Path Engagement API
  description: The Engagement API from Return Path — 35 operation(s) for engagement.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Engagement
  properties:
  - type: OpenAPI
    url: openapi/return-path-engagement-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-inbox-placement-api
  name: Return Path Inbox Placement API
  description: The Inbox Placement API from Return Path — 17 operation(s) for inbox placement.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Inbox Placement
  properties:
  - type: OpenAPI
    url: openapi/return-path-inbox-placement-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-infrastructure-dmarc-api
  name: Return Path Infrastructure (DMARC) API
  description: The Infrastructure (DMARC) API from Return Path — 10 operation(s) for infrastructure (dmarc).
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Infrastructure (DMARC)
  properties:
  - type: OpenAPI
    url: openapi/return-path-infrastructure-dmarc-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-legacy-api-1-0-api
  name: Return Path Legacy API (1.0) API
  description: The Legacy API (1.0) API from Return Path — 6 operation(s) for legacy api (1.0).
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Legacy API (1.0)
  properties:
  - type: OpenAPI
    url: openapi/return-path-legacy-api-1-0-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-list-validation-api
  name: Return Path List Validation API
  description: The List Validation API from Return Path — 6 operation(s) for list validation.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - List Validation
  properties:
  - type: OpenAPI
    url: openapi/return-path-list-validation-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-reputation-api
  name: Return Path Reputation API
  description: The Reputation API from Return Path — 18 operation(s) for reputation.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - Reputation
  properties:
  - type: OpenAPI
    url: openapi/return-path-reputation-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
- aid: return-path:return-path-view-time-optimization-api
  name: Return Path View Time Optimization API
  description: The View Time Optimization API from Return Path — 4 operation(s) for view time optimization.
  humanURL: https://developer.everest.validity.com/
  baseURL: https://api.everest.validity.com/api
  tags:
  - View Time Optimization
  properties:
  - type: OpenAPI
    url: openapi/return-path-view-time-optimization-api-openapi.yml
  - type: Postman
    url: collections/return-path-everest-api.postman_collection.json
  - type: Documentation
    url: https://developer.everest.validity.com/
  - type: APIReference
    url: https://developer.everest.validity.com/
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Overlay
  url: overlays/return-path-everest-api-overlay.yaml
- type: Website
  url: https://www.returnpath.com/
- type: Product
  url: https://www.validity.com/capabilities/engage-inbox-placement-and-deliverability/
- type: Blog
  url: https://www.validity.com/blog/
- type: Support
  url: https://knowledge.validity.com/hc/en-us
- type: HelpCenter
  url: https://knowledge.validity.com/hc/en-us
- type: Community
  url: https://mycommunity.validity.com/
- type: PrivacyPolicy
  url: https://www.validity.com/privacy-policy/
- type: TermsOfService
  url: https://www.validity.com/legal/terms-of-service/
- type: DeveloperPortal
  name: Everest API developer portal
  url: https://developer.everest.validity.com/
- type: Documentation
  url: https://developer.everest.validity.com/
- type: APIReference
  url: https://developer.everest.validity.com/
- type: Postman
  name: Everest by Validity public Postman workspace
  url: https://www.postman.com/two50okay/workspace/everest-by-validity-s-public-workspace/overview
- type: Login
  name: Everest sign in
  url: https://everest.validity.com/login
- type: TrustCenter
  url: https://trust.validity.com/
- type: Compliance
  url: https://trust.validity.com/
- type: Security
  url: https://trust.validity.com/
- type: TrustCenter
  name: Trust Center (artifact)
  url: security/return-path-trust-center.yml
- type: Compliance
  name: Published compliance program (SOC 2, ISO 27001/27701)
  url: security/return-path-trust-center.yml
- type: VulnerabilityDisclosure
  url: security/return-path-vulnerability-disclosure.yml
- type: Security
  name: Security contact / disclosure
  url: security/return-path-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/return-path-domain-security.yml
- type: Authentication
  url: authentication/return-path-authentication.yml
- type: Conventions
  url: conventions/return-path-conventions.yml
- type: ErrorCatalog
  url: errors/return-path-problem-types.yml
- type: RateLimits
  url: rate-limits/return-path-rate-limits.yml
- type: Plans
  url: plans/return-path-plans-pricing.yml
- type: Lifecycle
  url: lifecycle/return-path-lifecycle.yml
- type: Webhooks
  name: Everest Universal Endpoint webhook surface
  url: asyncapi/return-path-webhooks.yml
- type: DataModel
  url: data-model/return-path-data-model.yml
- type: Conformance
  url: conformance/return-path-conformance.yml
- type: Packages
  url: packages/return-path-packages.yml
- type: AgentSkill
  url: skills/_index.yml
- type: LLMsTxt
  name: llms.txt served by validity.com, the host that now serves Return Path
  url: llms/return-path-llms.txt
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 16
  pass: local-v1

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