emerging · -2.6 market domain

Deliverability

Score 23.5 / 100 28 providers +12 via APIs 20 APIs Search apis.io →
Business capabilities this tag reaches
Application Communications 2

Providers using this tag (28)

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

Exemplar 9 Complete, well-documented, and agent-ready
InstantlyCold EmailOutboundSales2 APIs67.8DeBounceEmail VerificationDisposable Email DetectionMX Records3 APIs67.0SendGridEmailEmail APIMarketing EmailSMTP44 APIs84.0lemlistEmail OutreachSales EngagementCold EmailSales Automation2 APIs76.0SvixWebhookWebhooks As A ServiceWebhook DeliveryWebhook Sending1 API74.7SMTP2GOEmailEmail DeliveryTransactional EmailSMTP1 API71.1PostmarkEmailMessagingTransactional Email3 APIs70.5MailosaurEmail TestingSMS TestingDeveloper ToolsQA Automation1 API68.0MailboxlayerEmailEmail VerificationSMTPMX Records2 APIs67.8
Strong 9 Solid coverage with minor gaps
KickboxEmail VerificationData QualityEmail2 APIs61.1CommsHarborEmailTransactional EmailEmail MarketingCommunications1 API60.4MailflossEmail VerificationMarketingSoftware-as-a-ServiceAutomation2 APIs60.3SmartleadCold EmailOutboundSales1 API60.2ValimailEmail AuthenticationDMARCEmail SecuritySPF3 APIs65.6NeverBounceEmail VerificationEmail HygieneMarketing1 API63.0Benchmark EmailEmail MarketingCampaignsContactsAutomation2 APIs62.7MailerSendEmailTransactional EmailSMTPMarketing1 API57.5EmailRepSecurityEmailEmail ReputationThreat Intelligence1 API55.7
Developing 8 Usable, with meaningful gaps to close
Email Verifier APIEmail VerificationSMTP CheckBounce Prevention1 API52.1SendBridgeEmailVerificationValidation1 API50.1Return PathCompanyMarTechEmailEmail Deliverability11 APIs44.5adbtdEmail InfrastructureSMTPIMAPDedicated IP1 API43.9Free Email Spam TesterEmailSpamTesting1 API40.1ClearBounceEmail VerificationList CleaningForm Validation2 APIs39.5uCheckerEmail VerificationEmailSMTPDNS1 API49.4tryverifyemail-comCompanyEmail VerificationData Validation1 API48.7
Thin 1 Limited public surface area
SendHQEmail APITransactional EmailInbound Email1 API33.1
Emerging 1 Early or largely undocumented
GlockAppsEmailSoftware-as-a-ServiceMarketing1 API23.7

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 11 Complete, well-documented, and agent-ready
lemlist Deliverability Alerts APIThreshold alerts on deliverability metrics - create, read, update and delete.76.0lemlist Email Accounts APIConnect, test and disconnect custom SMTP/IMAP sending accounts.76.0lemlist Lemwarm APIlemwarm mailbox warm-up - start, pause, and read or update warm-up settings per mailbox.76.0Address Validation APIValidate and standardize addresses, returning deliverability verdicts, geocodes, and address component deta...73.6Encharge Email Domain Settings APIThe email settings API from Encharge — 5 operation(s) for adding and verifying sending domains.71.8Gmail Postmaster Tools APIGather statistics on bulk emails sent to Gmail users including spam reports and delivery errors.70.7Live Direct Marketing Deliverability APIThe Deliverability API from Live Direct Marketing — 11 operation(s) for deliverability.68.7Snov.io Email Warm-up APICreate and manage email warm-up campaigns to improve deliverability scores. Supports full CRUD operations o...68.5kawaa-com Deliverability APIHow a domain is set up to send mail.68.0Mailboxlayer Email Validation APIREST/JSON API for real-time email validation: syntax check, typo suggestions, MX-record lookup, SMTP verifi...67.8sendly-now Deliverability APIWhy mail from one of your domains is or is not arriving: DNS identity, recent delivery outcomes, and one re...67.4
Strong 5 Solid coverage with minor gaps
NeverBounce API v4RESTful JSON API for email verification. Provides single email verification (`/single/check`), bulk job ver...63.0groundmail-dev Deliverability APIBest-effort metrics computed from stored email events61.3Kickbox Email Verification APIREST API for verifying the deliverability of email addresses in real time. Returns a result (deliverable, u...61.1agentisend-com Deliverability APIThe deliverability API from agentisend-com — 4 operation(s) for deliverability.60.4Smartlead Email Warmup APIEndpoints for managing Smartlead's deliverability warmup engine — enabling warmup per mailbox, configuring ...60.2
Developing 2 Usable, with meaningful gaps to close
Pabbly Email Verification APIREST API for Pabbly Email Verification. A single operation, POST /email-lists/verify-single, returning a de...53.6Deeplead Deliverability APIThe Deliverability API from Deeplead — 2 operation(s) for deliverability.45.6
Thin 2 Limited public surface area
SendHQ Deliverability APIInspect events, reputation outcomes, and blocked recipients.33.1Mailgun Email Validation APIREST API for verifying email addresses in real time, bulk list validation, and deliverability scoring to re...31.6

Companies reaching this through an API (12)

These companies publish an API, specification or operation carrying “Deliverability” but do not classify their business under it. Listed unranked and kept out of the count above, because one tagged operation is not a statement about what a company does.

agentisend-com Deeplead Encharge Google Maps Platform Google Workspace groundmail-dev kawaa-com Live Direct Marketing Mailgun Pabbly sendly-now Snov.io

Score breakdown

Frequency
44.3
log-scaled weighted occurrences
Breadth
0.4
spread across providers
Quality lift
57.8
mean composite of providers using it
Cohesion
5.2
strength of nearest seed neighbor

Related tags

SMTP 11 co-occurrences Email Verification 17 co-occurrences Transactional Email 11 co-occurrences DMARC 6 co-occurrences Cold Email 5 co-occurrences Email Marketing 6 co-occurrences Email 22 co-occurrences

Where this tag comes from

Provider tag28
Api tag20
Openapi tag5
Openapi op tag23

Cohort brief

Auto-generated

The 27 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
27
of 28 in the catalog
Mean Kin Score
58.1
+34.0 vs catalog 24.1
Mean Agent Readiness
41.9
+27.8 vs catalog 14.1
Spread
23.7–84
median 60.4 · σ 13.8
How the 27 split by band
Exemplar 9Strong 9Developing 7Thin 1Emerging 1Minimal 0
Facet averages, against the whole catalog
FacetThis cohortCatalogDifferenceScored
Access Clarity 71.7 30 +41.7 27
Developer Ergonomics 65.2 24.5 +40.7 27
Contract Quality 52.7 18.6 +34.1 27
Operational Transparency 41.5 13.2 +28.3 27
Contract Governance 24.9 9.7 +15.2 27
Discoverability 71.7 59.1 +12.6 27

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) 70% 18% +52
MCP server (first-party) 70% 16% +54
Agent Skills 0% 0% 0
OAuth scopes 26% 13% +13
Security 96% 99% -3
Arazzo workflows 11% 1% +10
Governance rules 96% 36% +60

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 SendGrid 84
  2. 2 lemlist 76
  3. 3 Svix 74.7
  4. 4 SMTP2GO 71.1
  5. 5 Postmark 70.5
  6. 6 Mailosaur 68
  7. 7 Instantly 67.8
  8. 8 Mailboxlayer 67.8
  9. 9 DeBounce 67
  10. 10 Valimail 65.6
Top by Agent Readiness
  1. 1 lemlist 65
  2. 2 Mailfloss 62.6
  3. 3 DeBounce 60.8
  4. 4 Instantly 60.5
  5. 5 MailerSend 56.3
  6. 6 Svix 53.1
  7. 7 tryverifyemail-com 49.9
  8. 8 CommsHarbor 47.7
  9. 9 NeverBounce 44.7
  10. 10 uChecker 44.3
All 28 members of this roster resolve to a provider in the catalog; 27 carry a score (96%). The figures above describe the scored members only.Generated from the catalog build of 14 November 2026, across 41591 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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Tools for tags

7 MCP tools reach this
  • find_tagsBrowse and filter every tag in the catalog.
  • get_cohortThis tag as a scored cohort — every provider carrying it, with scores.
  • cohort_statsPRO — the distribution across this tag: mean, median, band split, adoption rates.
  • cohort_rankingsPRO — the leaderboard, on composite AND agent-readiness axes.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
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