Vessel
Vessel (Kinit Inc.) is a developer-first embedded integrations platform for go-to-market software. It gives a product team one contract to read and write an end customer's CRM, sales engagement, chat, dialer and marketing automation tools, plus a drop-in browser component — Vessel Link — that handles the end user's authorization so the host application never touches downstream credentials. Three modules sit on an open-source integrations library: Unification (one normalized schema per vertical), Actions (typed, validated wrappers over a single provider's native API), and Managed ETL. An /api/passthrough endpoint forwards arbitrary authenticated requests for anything the modules do not cover. Vessel publishes 20 OpenAPI 3.1.0 definitions covering 376 operations in its own documentation repository. As of 2026-08-13 those contracts are still public but the operational surface is not: api.vessel.dev does not answer, api.vessel.land has no DNS record, and both docs.vessel.dev and app.vessel.dev are unreachable.
Solid contracts, transparent operations, and an easy start — typically complete on four or five facets with one clear soft spot.
API Evangelist profiles Vessel the way a machine reads it — 55 machine-readable artifacts across 20 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Vessel scores 64.0/100 (strong), with a separate agent-readiness read of 33/100 (agent ready). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance. Every facet and dimension name is a link: it opens that measurement's page on APIs.io, where the rating runs across the whole catalog — the exact checks that feed it, how every profiled provider distributes on it, and who is at the top of it.
Kin Score
How this is scored →scored 2026-09-08 · rubric v0.20.0
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How we profile Vessel
Each block below is one kind of artifact we hold for Vessel. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 37
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Vessel Accounts API
The accounts API from Vessel — 7 operation(s) for accounts.
Vessel Actions API
The Actions API from Vessel — 115 operation(s) for actions.
Vessel Attendees API
The attendees API from Vessel — 5 operation(s) for attendees.
Vessel Auth API
The Auth API from Vessel — 6 operation(s) for auth.
Vessel Connection API
The Connection API from Vessel — 1 operation(s) for connection.
Vessel Connections API
The connections API from Vessel — 5 operation(s) for connections.
Vessel Contact Custom Fields API
The contactCustomFields API from Vessel — 1 operation(s) for contactcustomfields.
Vessel Contacts API
The contacts API from Vessel — 5 operation(s) for contacts.
Vessel CRM API
The Crm API from Vessel — 9 operation(s) for crm.
Vessel Deals API
The deals API from Vessel — 5 operation(s) for deals.
Vessel Emails API
The emails API from Vessel — 5 operation(s) for emails.
Vessel Eng Accounts API
The engAccounts API from Vessel — 2 operation(s) for engaccounts.
Vessel Eng Accountss API
The engAccountss API from Vessel — 1 operation(s) for engaccountss.
Vessel Eng Actions API
The engActions API from Vessel — 3 operation(s) for engactions.
Vessel Eng Calls API
The engCalls API from Vessel — 2 operation(s) for engcalls.
Vessel Eng Contacts API
The engContacts API from Vessel — 3 operation(s) for engcontacts.
Vessel Eng Custom Fields API
The engCustomFields API from Vessel — 2 operation(s) for engcustomfields.
Vessel Eng Dispositions API
The engDispositions API from Vessel — 1 operation(s) for engdispositions.
Vessel Eng Emails API
The engEmails API from Vessel — 3 operation(s) for engemails.
Vessel Eng Mailboxes API
The engMailboxes API from Vessel — 1 operation(s) for engmailboxes.
Vessel Eng Passthrough API
The engPassthrough API from Vessel — 1 operation(s) for engpassthrough.
Vessel Eng Sequences API
The engSequences API from Vessel — 4 operation(s) for engsequences.
Vessel Eng Tasks API
The engTasks API from Vessel — 3 operation(s) for engtasks.
Vessel Eng Users API
The engUsers API from Vessel — 2 operation(s) for engusers.
Vessel Events API
The events API from Vessel — 5 operation(s) for events.
Vessel Integrations API
The integrations API from Vessel — 2 operation(s) for integrations.
Vessel Lead Custom Fields API
The leadCustomFields API from Vessel — 1 operation(s) for leadcustomfields.
Vessel Leads API
The leads API from Vessel — 5 operation(s) for leads.
Vessel Links API
The links API from Vessel — 1 operation(s) for links.
Vessel Lists API
The lists API from Vessel — 2 operation(s) for lists.
Vessel Notes API
The notes API from Vessel — 5 operation(s) for notes.
Vessel Passthrough API
The passthrough API from Vessel — 2 operation(s) for passthrough.
Vessel Tasks API
The tasks API from Vessel — 5 operation(s) for tasks.
Vessel Tokens API
The tokens API from Vessel — 1 operation(s) for tokens.
Vessel Unifications API
The Unifications API from Vessel — 107 operation(s) for unifications.
Vessel Users API
The users API from Vessel — 5 operation(s) for users.
Vessel Webhooks API
The webhooks API from Vessel — 5 operation(s) for webhooks.
Scroll within the panel for all 37 ·
Pricing Plans 1
Pricing is part of the interface. Machine-readable plans tell you what a tier costs and includes before you commit — one of the things the Kin Score reads for access clarity — renamed from commercial clarity in rubric 0.12, because a free statutory interface has access terms and no commercial ones.
Published pricing tiers and plan structures.
Vessel Plans Pricing
PLANSRate Limits 1
Rate limits are the difference between a demo that works and a production integration that doesn't fall over. Publishing them is an operational-transparency signal — and a hard requirement for any agent that plans its own throughput.
Documented rate limits and quota policies.
Vessel Rate Limits
RATE LIMITSFinOps 1
Cost, billing, and metering signals let a buyer model the financial operations of an API before it's live. We profile them for the same reason we profile pricing: the money is part of the contract.
Cost, billing, and metering signals for API financial operations.
Vessel Finops
FINOPSEvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Vessel Webhooks
ASYNCAPISemantic Vocabularies 1
JSON-LD contexts give the data shared meaning across APIs. We profile them because semantics are what let a machine reconcile 'customer' here with 'customer' somewhere else.
JSON-LD contexts and semantic vocabularies used across these APIs.
Vessel Context
JSON-LDSpectral Rules 2
Governance rulesets we run against this provider's specs — the automated checks behind parts of the score. Profiling them makes the quality bar explicit and re-runnable, not a matter of opinion.
Vessel API Rules
SPECTRALVessel API Rules
SPECTRALJSON Schema 3
Standalone JSON Schema definitions describe the data models behind the API. We profile them so the shapes are validatable on their own — useful long after a single request is forgotten.
Standalone JSON Schema definitions for this provider's data models.
JSON Structure 1
JSON Structure captures the data shapes in a form built for tooling — a complement to JSON Schema that keeps the model machine-legible.
JSON Structure definitions describing this provider's data shapes.
Vessel Contact Structure
JSON STRUCTUREExamples 4
Real request and response payloads are what turn a spec from abstract into obvious — and they're one of the twelve things an agent needs to call an API correctly on the first try.
Example request and response payloads for these APIs.
Security Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Vessel — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 2
Portal, sign-up, and the first successful call
Documentation 5
Reference material describing how the API behaves
Agent Surfaces 3
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 12
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 12 ·
Build 7
SDKs, sample code, and the tooling you integrate with
Scroll within the panel for all 7 ·
Access & Security 3
Authentication, authorization, and security posture
Operate 4
Status, limits, changes, and where to get help
Commercial 6
Pricing, plans, and the legal terms of use
Company 3
The organization behind the API
Other 3
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/vessel · machine-readable index on apis.io
This is an independent, third-party profile of Vessel, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.
The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.
Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.
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