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 13 Complete, well-documented, and agent-ready

HubSpot Leads APIThe leads API enables you to manage lead records in HubSpot. Leads are contacts or companies that are poten...82.4 Adobe Marketo Engage APIAutomate marketing processes and manage leads, campaigns, and assets via REST APIs.80.4 Leadping Leads APIManages lead intake, records, assignment, routing, and lifecycle operations. Use these endpoints to ingest ...72.2 Vessel CRM Unified APIThe Vessel CRM Unified API (v2) normalizes CRM objects across Salesforce, HubSpot, Zoho, Pipedrive, Close, ...72.1 Vessel Engagement API (v1, legacy)The first-generation Vessel Sales Engagement API, published under /engagement/* on api.vessel.land. Covers ...72.1 Hunter Leads APIManage leads stored in Hunter.71.4 Adobe Marketo Engage APIAccess and manage marketing automation data including leads, accounts, opportunities, campaigns, and assets...71.2 Microsoft Dynamics 365 Sales Leads APISales lead records69.9 Cvent Event Cloud Leads API* **Leads -** Leads include leads gathered by LeadCapture, Appointments, and Inbound Leads. Use this API to...69.6 Unbounce Leads APILead submissions captured by pages68.7 Unbounce REST APIREST API for Unbounce providing programmatic access to accounts, sub-accounts, domains, pages, page groups,...68.7 lemlist Leads APILeads inside campaigns - create with optional enrichment, update, pause, resume, mark interested, custom va...68.3 Instantly API v2The full Instantly REST API v2 — 129 paths, 173 operations across 28 resource groups, published as OpenAPI ...67.0

Strong 16 Solid coverage with minor gaps

ServiceNow Lead APIThe ServiceNow Lead API provides REST endpoints to create, update, and retrieve marketing leads and their a...64.8 SmartLead APIThe complete SmartLead REST API as published by SmartLead — OpenAPI 3.1.1, 85 paths and 98 operations acros...63.6 Smartlead Leads APIEndpoints to add leads to a campaign in bulk, fetch leads, update lead status (interested, replied, unsubsc...63.6 Nutshell Competitors APICompetitor records and the lead-to-competitor relationships (competitor maps) attached to a lead. 6 operati...60.8 Nutshell Leads APISales opportunities: create, read, update, close, reopen, watch, stage and stageset assignment, installment...60.8 Nutshell REST APINutshell's primary REST API — 87 paths and 112 operations across 24 resource families (accounts, contacts, ...60.8 Zendesk Sell (Sales CRM) APIOAuth 2.0-authenticated REST API for managing leads, contacts, deals, accounts, notes, tasks, calls, source...60.3 Zendesk Sell Leads APIPre-qualified sales prospects.60.3 Hustle Leads APIThe Leads API from Hustle — 1 operation(s) for leads.59.8 LeadSquared Leads APILead create, get, and search58.3 Zendesk Sell Leads APIThe Zendesk Sell Leads API provides a simple interface to manage leads. A lead represents an individual or ...58.1 Hunter Leads APILead management.56.8 Supaglue Leads APIThe `Lead` Common Object represents a "potential customer" in CRMs.56.3 Apideck Leads APIThe Lead resource represents individuals or businesses that have shown interest in a company's products or ...55.9 Facebook Lead Ads Leads APIThe Leads API from Facebook Lead Ads — 2 operation(s) for leads.55.9 Marketo Engage Lead Database APIThe core Marketo Engage REST surface — person ("lead") records, activity and data-value-change feeds, compa...55.7

Developing 39 Usable, with meaningful gaps to close

Makinari REST APICore Makinari platform API covering Visitors (tracking and identification), Finder (contact and company sea...54.2 ServiceTitan Leads APIPre-customer lead records53.5 Lawmatics OAuth APIRESTful OAuth API for managing leads, matters, contacts, intake forms, pipelines, and automated client foll...52.7 Housecall Pro Leads APIThe Leads API from Housecall Pro — 1 operation(s) for leads.52.6 PersistIQ Leads APILeads (prospects)51.9 Nimble Contacts Pipelines APIContact pipelines — the lead-progression surface for contacts, distinct from deal pipelines. 8 operation(s).51.2 Nimble Leads APILead transitions through contact pipelines — move a lead between stages, mark it exited successfully or uns...51.2 Nimble REST APIThe Nimble CRM REST API — 89 operations across contacts, contact custom fields, contact and deal pipelines,...51.2 Tripleseat Leads APICapture and retrieve leads, including the public lead form.51.1 Zoopla Leads APISwagger 2.0 poll API for retrieving applicant leads and appraisal (valuation) leads generated on the Zoopla...50.1 AutoLeadStar Leads APIOperations related to leads49.5 Nomos Leads APIThe Leads API from Nomos — 2 operation(s) for leads.49.5 SharpSpring Open APIThe SharpSpring (Constant Contact Lead Gen & CRM) Open API — a single HTTPS POST endpoint that accepts a JS...48.4 Eruditus Leads APIEnrollment lead submission.48.3 LendKey leads APIThe leads API from LendKey — 1 operation(s) for leads.48.3 Mobly REST API v0The Mobly REST API (v0) gives programmatic access to events, leads, lead activity events, activations, qual...48.2 Microsoft Leads APIManage leads47.8 Buildxact WebhooksBuildxact's webhook surface lets partner and customer integrations receive real-time notifications when eve...47.6 Flowise leads APIThe leads API from Flowise — 2 operation(s) for leads.47.5 Conversica Integrations APIJSON-over-HTTPS integration surface for the Conversica Platform. A customer system posts Lead objects to a ...46.6 Instapage Form Submissions APIRetrieve and permanently delete the lead records captured by forms on Instapage landing pages, paged with a...46.4 Pipedrive Leads APILeads are potential deals stored in Leads Inbox before they are archived or converted to a deal. Each lead ...45.7 WeTravel Leads APIThe Leads API from WeTravel — 2 operation(s) for leads.45.5 Oracle Fusion Cloud Applications Leads APIManage sales leads and qualification45.3 Fixture Leads APICreate, read, update, and convert Leads.44.3 Dealer.com Leads APILead generation and management capability - pre-qualification, messaging, and customer-engagement tools tha...44.1 Avoca Leads APIUnified leads (v0) and the canonical leads feed (v1)44.0 Copper Leads APILead records and conversion43.3 REALTOR.ca DDF Lead APIThe DDF Lead API is a single documented POST endpoint, /v1/Lead/CreateLead, on the same ddfapi.realtor.ca h...42.1 Proton.ai Leads APIThe Leads API from Proton.ai — 3 operation(s) for leads.40.9 Root Insurance Leads APIThe Leads API from Root Insurance — 2 operation(s) for leads.40.6 Chatbase Leads APIRetrieve leads captured by a chatbot.40.0 Unstoppable Domains Leads APIDomain conversations and messaging between buyers and sellers (requires authentication)39.5 Anywhere Agent Recruiting APIAn endpoint for third-party CRM integration partners to deliver recruiting activities into Anywhere's iPros...39.3 Anywhere Leads Engine APIHandles ingestion, routing and assignment of leads for Anywhere brands. Listed on the developer portal home...39.3 Anywhere Leads Management APIPowers third-party CRM applications to sync lead data with Anywhere source systems so agents can manage lea...39.3 Anywhere Referral Leads APISubmit a new lead to Anywhere's referral platform for a specific real estate referral program and share sta...39.3 Anywhere Referral Partner Integration APISubmit a new lead to Anywhere's referral platform for a specific real estate referral program, creating a c...39.3 Rentberry Leads APILeads39.3

Thin 24 Limited public surface area

Z League Leads APIThe Leads API from Z League — 2 operation(s) for leads.38.7 Zoho CRMThe Zoho CRM API provides REST endpoints and client libraries for Java, PHP, Python, and Node.js, allowing ...38.5 Phorest Leads APIMarketing leads and lead statistics.38.3 REALTOR.ca DDF Lead APIThe DDF® Lead API accepts an email lead for a REALTOR® from a downstream site. Because member email address...38.3 Zoopla Leads APIPoll-based REST API used by Zoopla member agents to retrieve consumer leads generated on the portal. Applic...37.9 Brightcove Leads APIGet leads for a Video Cloud account.37.2 Microsoft Dynamics Leads APIThe Leads API from Microsoft Dynamics — 2 operation(s) for leads.36.1 Thumbtack Leads APIThe Leads API from Thumbtack — 2 operation(s) for leads.36.1 Zillow Tech ConnectZillow Tech Connect is the partner program that lets approved real-estate software vendors integrate with Z...35.0 Workiz Leads APIProspective work that can be converted into jobs.34.7 Apex27 CRM APIThe Apex27 CRM API is the vendor's REST interface over the estate agency CRM, covering contacts, leads, lis...31.9 AlterEstate Leads APIInbound lead submission into the CRM31.8 freshworks Leads APIManage sales leads before they are converted to contacts or accounts.31.6 USADATA Leads Engine Service (SOAP)Publicly served SOAP 1.1 / 1.2 web service behind the USADATA Leads Portal and Leads Module. The WSDL is se...31.0 Insightly Leads APIThe Leads API from Insightly — 1 operation(s) for leads.30.7 Insightly REST API v3.1REST API for managing contacts, organizations, leads, opportunities, projects, tasks, events, products, pri...30.7 Swapcard Exhibitor Leads APIExhibitor-facing GraphQL API to list accessible booths (myExhibitors), export event leads with cursor pagin...30.3 DealerSocket CRM & Leads APILead and CRM integration surface. Includes the outbound Lead Forwarding Service (forwards incoming and proc...30.0 SmartMoving Leads APISales pipeline leads and their statuses.29.6 Realtor.com Connections Plus APIThe Realtor.com Connections Plus API provides a direct connection between the Realtor.com lead delivery sys...29.2 Realtor.com Lead Delivery APIThe Realtor.com Lead Delivery API is an end-to-end integration layer that delivers real estate leads direct...29.2 Allianz Leads APIOperations for submitting insurance leads to the Allianz sales team27.4 AgencyZoom Leads APIThe Leads API from AgencyZoom — 8 operation(s) for leads.27.2 Wodify Leads APIProspective members and their conversion to clients.26.2

Emerging 8 Early or largely undocumented

Glofox Leads APICapture prospective members as leads and convert them into paying members through the "Lead Sale" integrati...21.8 Glofox Members APIAccess, create, and edit member records - the central pivot of the Glofox data model, spanning leads, activ...21.8 Follow Up Boss APIREST API for managing real estate leads, contacts, deals, notes, tasks, calls, text messages, events, and w...21.7 Hostfully REST APIHostfully Property Management Platform REST API v3.x covering properties (single and multi-unit), leads (in...18.9 OnTheMarket Real Time Datafeed (RTDF) APIOnTheMarket's member-only feed API for estate-agency CRM software. It is modelled on the Rightmove Real Tim...16.2 Angi Leads Delivery (Webhook) APINot a self-serve public API - there is no published base URL, API reference, or API key signup. Once a pro ...15.1 FranConnect Franchise Sales APIFranchise Sales / Development module (path segment "fs"). Import and export franchise development leads, pr...15.1 Contractor Foreman Zapier Automation APIA private, account-scoped REST API reached with an API key generated under Settings > Integration > Zapier,...13.8

Minimal 2 Almost no public developer surface

HomeLight Partner APIPartner-gated REST API for submitting buyer and seller leads to HomeLight, submitting Simple Sale cash-offe...9.0 MoveitPro Leads APISales leads captured from websites, lead providers, and Zillow. Modeled from the documented MoveitPro Zapie...7.0

Score breakdown

Frequency

63.2

log-scaled weighted occurrences

Breadth

2.4

spread across providers

Quality lift

55.1

mean composite of providers using it

Cohesion

11.8

strength of nearest seed neighbor

Where this tag comes from

Api tag100

Provider tag15

Openapi tag52

Openapi op tag220

Cohort brief

Auto-generated

The 89 providers in the APIs.io catalog tagged Leads, scored on the Kin Score. Every figure below is computed from the catalog — nothing here is written.

Providers

all scored

Mean Kin Score

44.5

+23.8 vs catalog 20.7

Mean Agent Readiness

+18.3 vs catalog 9.7

Spread

7–82.4

median 45.3 · σ 16.3

How the 89 split by band

Exemplar 11Strong 12Developing 33Thin 23Emerging 8Minimal 2

Facet averages, against the whole catalog

Facet	This cohort	Catalog	Difference	Scored
Contract Quality	48.9	17.5	+31.4	89
Developer Ergonomics	43	17.9	+25.1	89
Access Clarity	47.4	22.3	+25.1	89
Operational Transparency	34.2	11.3	+22.9	89
Discoverability	73.6	60.4	+13.2	89
Contract Governance	16.7	6.4	+10.3	89

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

Artifact	This cohort	Catalog	Difference
MCP server (any)	47%	16%	+31
MCP server (first-party)	22%	7%	+15
Agent Skills	0%	0%	0
OAuth scopes	38%	9%	+29
Security	100%	88%	+12
Arazzo workflows	9%	2%	+7
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 HubSpot 82.4
2 Adobe 80.4
3 Leadping 72.2
4 Vessel 72.1
5 Hunter 71.4
6 Adobe Suite 71.2
7 Microsoft Dynamics 365 Sales 69.9
8 Cvent Event Cloud 69.6
9 Unbounce 68.7
10 lemlist 68.3

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Leads

Providers using this tag (89)

APIs with this tag (102)