established ↑ 6.0

Newsletters

Score 24.8 / 100 26 providers 10 APIs Search apis.io →

Providers using this tag (26)

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

Exemplar 11 Complete, well-documented, and agent-ready
Customer.ioBehavioral DataBroadcastsCampaignsCDP27 APIs87.3KitEmail MarketingCreator EconomySubscribersAutomation14 APIs85.6MailchimpCampaignsEmail MarketingMarketing Automation120 APIs81.5MailerLiteEmail MarketingAutomationSubscribers9 APIs77.2GhostPublishingMembershipsSubscription19 APIs74.4GetResponseEmail MarketingMarketing AutomationLanding PagesWebinars50 APIs74.1AWeberEmail MarketingMarketing AutomationEmail12 APIs73.5ButtondownAnalyticsAutomationsEmailMarkdown30 APIs71.5Campaign MonitorEmail MarketingCampaignsSubscribersTransactional Email1 API71.4MoosendEmail MarketingMarketing AutomationCampaignsMailing Lists1 API67.9Dow JonesFinancialMarket DataNewsPublishing18 APIs66.8
Strong 4 Solid coverage with minor gaps
FactivaArtificial IntelligenceBusiness IntelligenceContent AggregationEnterprise Data11 APIs61.9ParagraphCompanyPublishingWeb310 APIs60.8EmailOctopusEmailEmail MarketingCampaigns6 APIs60.5HashnodeBloggingDeveloper PlatformGraphQLContent Management1 API57.0
Developing 2 Usable, with meaningful gaps to close
MailOptinCompanyEmail MarketingMarketing AutomationLead Generation1 API46.5KitEmail MarketingCreator EconomyAutomation4 APIs43.2
Thin 4 Limited public surface area
JeengCompanyAdvertisingPublishingEmail3 APIs37.6SubstackPublishingCreator EconomySubscription3 APIs32.2National Tsing Hua UniversityEducationHigher EducationUniversityTaiwan9 APIs30.9backstitchCompanyContent CurationEmployee CommunicationsInternal Communications1 API30.2
Emerging 4 Early or largely undocumented
BetaListStartupsBeta TestingProduct DiscoveryEarly Adopters1 API23.8SmoreCompanyEducationEdTech15.1PicoCompanyCreator EconomyCRMMemberships1 API14.2ReDEFCompanyMediaCuration13.1
Minimal 1 Almost no public developer surface
FanbridgeCompanyEmail MarketingSMS MarketingMusic5.0

APIs with this tag (10)

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 7 Complete, well-documented, and agent-ready
Customer.io App APIThe Customer.io App API is the workspace-management and outbound-messaging surface: trigger broadcasts, sen...87.3Customer.io Newsletters APIRetrieve information about newsletters and newsletter variants.87.3GetResponse API v3The complete GetResponse API v3 — a JSON REST API of 220 operations across 141 paths and 42 product areas, ...74.1GetResponse Newsletters APINewsletters API documentation The Newsletters area of the GetResponse API v3 — 10 operation(s) across 8 pat...74.1Buttondown Newsletter PlatformThe Buttondown hosted newsletter platform provides a markdown-based composition experience, subscriber mana...71.5Buttondown Newsletters APIThe Newsletters API from Buttondown — 7 operation(s) covering newsletter settings, branding, locale, and cu...71.5Dow Jones Factiva Newsletters APIRetrieve Factiva newsletter editions and collections.66.8
Strong 1 Solid coverage with minor gaps
DJ Factiva Newsletters APIRetrieve the Factiva newsletters available to an account, walk each newsletter's editions and deliveries, a...61.9
Thin 2 Limited public surface area
Jeeng Email Monetization — Publishers APIPublisher-side inventory reporting for the Jeeng / OpenWeb Email Monetization platform. Retrieve container ...37.6National Tsing Hua University Newsletters APIThe Newsletters API from National Tsing Hua University — 2 operation(s) for newsletters.30.9

Score breakdown

Frequency
44.1
log-scaled weighted occurrences
Breadth
0.7
spread across providers
Quality lift
63.7
mean composite of providers using it
Cohesion
5.9
strength of nearest seed neighbor

Related tags

Subscribers 9 co-occurrences Email Marketing 12 co-occurrences Transactional Email 7 co-occurrences Landing Pages 5 co-occurrences Segments 8 co-occurrences Marketing Automation 8 co-occurrences Publishing 7 co-occurrences Creator Economy 5 co-occurrences

Where this tag comes from

Provider tag22
Api tag10
Openapi tag4
Openapi op tag20

Cohort brief

Auto-generated

The 26 providers in the APIs.io catalog tagged Newsletters, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.

Providers
26
all scored
Mean Kin Score
52.4
+31.7 vs catalog 20.7
Mean Agent Readiness
29.6
+19.9 vs catalog 9.7
Spread
5–87.3
median 60.7 · σ 24.6
How the 26 split by band
Exemplar 11Strong 4Developing 2Thin 4Emerging 4Minimal 1
Facet averages, against the whole catalog
FacetThis cohortCatalogDifferenceScored
Access Clarity 63.9 22.3 +41.6 26
Developer Ergonomics 50.4 17.9 +32.5 26
Operational Transparency 42.6 11.3 +31.3 26
Contract Quality 45.3 17.5 +27.8 26
Discoverability 77.6 60.4 +17.2 26
Contract Governance 20.8 6.4 +14.4 26

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) 54% 16% +38
MCP server (first-party) 35% 7% +28
Agent Skills 0% 0% 0
OAuth scopes 46% 9% +37
Security 96% 88% +8
Arazzo workflows 4% 2% +2
Governance rules 27% 13% +14

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 Customer.io 87.3
  2. 2 Kit 85.6
  3. 3 Mailchimp 81.5
  4. 4 MailerLite 77.2
  5. 5 Ghost 74.4
  6. 6 GetResponse 74.1
  7. 7 AWeber 73.5
  8. 8 Buttondown 71.5
  9. 9 Campaign Monitor 71.4
  10. 10 Moosend 67.9
Top by Agent Readiness
  1. 1 Kit 61
  2. 2 Customer.io 50.4
  3. 3 GetResponse 50.4
  4. 4 MailerLite 49.1
  5. 5 Dow Jones 48.4
  6. 6 Mailchimp 44.8
  7. 7 Factiva 43.3
  8. 8 Paragraph 42.3
  9. 9 Buttondown 41.2
  10. 10 AWeber 37.2
All 26 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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Tools for tags

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  • 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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