established ↑ 5.2

Deliverability

Score 27.0 / 100 29 providers 20 APIs Search apis.io →
Variants seen in the corpus: Deliverabilitydeliverability

Providers using this tag (29)

Ranked by API Evangelist rating — Exemplar and Strong are expanded by default.

Exemplar 13 Complete, well-documented, and agent-ready
Amazon SESEmailEmail DeliverabilityEmail ServiceMarketing Email17 APIs79.7SvixWebhookWebhooks As A ServiceWebhook DeliveryWebhook Sending21 APIs79.2SendGridEmailEmail APIMarketing EmailSMTP63 APIs77.0SendPulseMarketingMarketing AutomationEmailTransactional Email19 APIs75.7SMTP2GOEmailEmail DeliveryTransactional EmailSMTP11 APIs73.6MailboxlayerEmailEmail VerificationEmail ValidationSMTP2 APIs73.4DeBounceEmail ValidationEmail VerificationDisposable Email Detection6 APIs71.8PostmarkEmailsMessagingTransactional Email47 APIs71.1MailosaurEmail TestingSMS TestingDeveloper ToolsQA Automation7 APIs71.0lemlistEmail OutreachSales EngagementCold EmailSales Automation22 APIs68.3Snov.ioSales AutomationEmail FinderEmail VerificationLead Generation17 APIs67.8Lob.comCompanyDirect MailPrintAddress Verification32 APIs67.5InstantlyCold EmailOutboundSales2 APIs67.0
Strong 9 Solid coverage with minor gaps
Benchmark EmailEmail MarketingCampaignsContactsAutomation30 APIs64.6MailerSendEmailTransactional EmailSMTPMarketing8 APIs64.6ValimailEmail AuthenticationDMARCEmail SecuritySPF17 APIs64.6SmartleadCold EmailOutboundSales11 APIs63.6NeverBounceEmail VerificationEmail ValidationEmail Hygiene5 APIs62.2KickboxEmail VerificationEmail ValidationData Quality5 APIs57.9EnchargeEmail MarketingMarketing AutomationTransactional EmailSoftware-as-a-Service16 APIs57.3PabblyAutomationEmail MarketingSubscription BillingBilling7 APIs57.3Email Verifier APIEmail VerificationSMTP CheckBounce Prevention1 API56.8
Developing 5 Usable, with meaningful gaps to close
Google Maps PlatformEnvironmentGeocodingGeolocationMaps41 APIs49.8EmailRepSecurityEmailEmail ReputationThreat Intelligence2 APIs48.4uCheckerEmail VerificationEmailSMTPDNS3 APIs48.0Google WorkspaceCalendarCollaborationEmailProductivity29 APIs47.5Return PathCompanyMarTechEmailEmail Deliverability1 API41.4
Thin 1 Limited public surface area
MailgunEmailTransactional EmailSMTPEmail Validation8 APIs34.0
Emerging 1 Early or largely undocumented
InboxEmailInboxMessaging2 APIs13.4

APIs with this tag (20)

Ranked by the provider's API Evangelist rating — the Kin Score is scored per provider, not per API, so every API of a provider shares its band. How the rating works →

Exemplar 10 Complete, well-documented, and agent-ready
Amazon SES v2 APIThe full Amazon Simple Email Service v2 API (API version 2019-09-27) — 86 operations across email sending, ...79.7SendPulse SMTP APITransactional email sending, delivery and bounce tracking, unsubscribe management and sender-domain identity.75.7SendPulse Verifier APIEmail address verification and mailing-list cleaning to identify invalid, disposable or high-risk contacts ...75.7SMTP2GO Email APIREST API for sending transactional emails and SMS, managing sender domains, SMTP users, API keys, templates...73.6Mailboxlayer Email Validation APIREST/JSON API for real-time email validation: syntax check, typo suggestions, MX-record lookup, SMTP verifi...73.4lemlist Deliverability Alerts APIThreshold alerts on deliverability metrics - create, read, update and delete.68.3lemlist Email Accounts APIConnect, test and disconnect custom SMTP/IMAP sending accounts.68.3lemlist lemwarm APIlemwarm mailbox warm-up - start, pause, and read or update warm-up settings per mailbox.68.3Snov.io Email Warm-up APICreate and manage email warm-up campaigns to improve deliverability scores. Supports full CRUD operations o...67.8Instantly API v2The full Instantly REST API v2 — 129 paths, 173 operations across 28 resource groups, published as OpenAPI ...67.0
Strong 6 Solid coverage with minor gaps
SmartLead APIThe complete SmartLead REST API as published by SmartLead — OpenAPI 3.1.1, 85 paths and 98 operations acros...63.6Smartlead Email Warmup APIEndpoints for managing Smartlead's deliverability warmup engine — enabling warmup per mailbox, configuring ...63.6NeverBounce API v4RESTful JSON API for email verification. Provides single email verification (`/single/check`), bulk job ver...62.2Kickbox Email Verification APIREST API for verifying the deliverability of email addresses in real time. Returns a result (deliverable, u...57.9Encharge Email Domain Settings APIThe email settings API from Encharge — 5 operation(s) for adding and verifying sending domains.57.3Pabbly Email Verification APIREST API for Pabbly Email Verification. A single operation, POST /email-lists/verify-single, returning a de...57.3
Developing 2 Usable, with meaningful gaps to close
Address Validation APIValidate and standardize addresses, returning deliverability verdicts, geocodes, and address component deta...49.8Gmail Postmaster Tools APIGather statistics on bulk emails sent to Gmail users including spam reports and delivery errors.47.5
Thin 1 Limited public surface area
Mailgun Email Validation APIREST API for verifying email addresses in real time, bulk list validation, and deliverability scoring to re...34.0
Emerging 1 Early or largely undocumented
Mailgun Email APIMailgun provides a programmable email API for sending, receiving, tracking, and validating email at scale. ...13.4

Score breakdown

Frequency
43.7
log-scaled weighted occurrences
Breadth
0.8
spread across providers
Quality lift
74.5
mean composite of providers using it
Cohesion
6.3
strength of nearest seed neighbor

Related tags

SMTP 11 co-occurrences Email Verification 11 co-occurrences Email Validation 7 co-occurrences Transactional Email 10 co-occurrences Data Quality 6 co-occurrences Email 15 co-occurrences Email Marketing 5 co-occurrences Campaigns 8 co-occurrences

Where this tag comes from

Api tag20
Provider tag21

Cohort brief

Auto-generated

The 29 providers in the APIs.io catalog tagged Deliverability, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.

Providers
29
all scored
Mean Kin Score
61.2
+40.5 vs catalog 20.7
Mean Agent Readiness
37.5
+27.8 vs catalog 9.7
Spread
13.4–79.7
median 64.6 · σ 14.5
How the 29 split by band
Exemplar 13Strong 9Developing 5Thin 1Emerging 1Minimal 0
Facet averages, against the whole catalog
FacetThis cohortCatalogDifferenceScored
Access Clarity 76.4 22.3 +54.1 29
Developer Ergonomics 64.5 17.9 +46.6 29
Contract Quality 59.3 17.5 +41.8 29
Operational Transparency 48.9 11.3 +37.6 29
Contract Governance 27.5 6.4 +21.1 29
Discoverability 78.8 60.4 +18.4 29

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.

What this cohort publishes
ArtifactThis cohortCatalogDifference
MCP server (any) 76% 16% +60
MCP server (first-party) 62% 7% +55
Agent Skills 0% 0% 0
OAuth scopes 34% 9% +25
Security 100% 88% +12
Arazzo workflows 17% 2% +15
Governance rules 45% 13% +32

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.

Top by Kin Score
  1. 1 Amazon SES 79.7
  2. 2 Svix 79.2
  3. 3 SendGrid 77
  4. 4 SendPulse 75.7
  5. 5 SMTP2GO 73.6
  6. 6 Mailboxlayer 73.4
  7. 7 DeBounce 71.8
  8. 8 Postmark 71.1
  9. 9 Mailosaur 71
  10. 10 lemlist 68.3
Top by Agent Readiness
  1. 1 DeBounce 69
  2. 2 lemlist 63.9
  3. 3 Instantly 62.7
  4. 4 SendPulse 55.8
  5. 5 MailerSend 50.2
  6. 6 Svix 49.9
  7. 7 Amazon SES 41.6
  8. 8 SendGrid 41.2
  9. 9 SMTP2GO 39.4
  10. 10 Postmark 38.7
All 29 members of this roster resolve to a scored provider in the catalog.Generated from the catalog build of 25 August 2026, across 26891 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.

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  • find_cohortsEvery scored population of providers in the catalog.
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