Primitive
Primitive is email infrastructure built for AI agents. It lets an agent send and receive email with a single authenticated HTTP call — no SMTP credentials, DNS, or mail servers — and hosts each agent at a managed *.primitive.email address that runs a JavaScript handler on every inbound message. The `primitive chat` verb sends a message and returns the threaded reply in one round trip. The v1 REST API (96 paths, 129 operations) covers domains, sending, inbound emails, threads, search, webhook endpoints, filters, routing, hosted Functions, durable Memories, an agent registry, wake scheduling, and non-custodial x402 USDC payments over email. Primitive ships a published hosted MCP server, an A2A agent card, a read-only GraphQL surface, official Node/Python/Go SDKs and a CLI, and a rich agent-native discovery surface (llms.txt, /.well-known/*, packaged Agent Skills). Backed by Y Combinator (Spring 2026).
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Primitive the way a machine reads it — 28 machine-readable artifacts across 22 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 — Primitive scores 58.2/100 (developing), with a separate agent-readiness read of 87/100 (agent native). 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.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Primitive
Each block below is one kind of artifact we hold for Primitive. 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 22
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.
Primitive Account API
Manage your account settings, storage, and webhook secret
Primitive Agent API
Agent signup and authentication
Primitive CLI API
Browser-assisted CLI authentication
Primitive Demo API
Public, no-account sandbox operations that mirror authenticated endpoints with synthetic data so an agent can learn the request and response shapes before signing up.
Primitive Discovery API
Unauthenticated entry point that lists the API base URL, how to obtain credentials, and the operations callable without a token.
Primitive Domains API
Claim, verify, and manage email domains
Primitive Emails API
List, inspect, and manage received emails
Primitive Endpoints API
Manage webhook endpoints that receive email events
Primitive Filters API
Manage whitelist and blocklist filter rules
Primitive Functions API
Deploy JavaScript handlers that run on inbound mail. Each function is a single ESM module whose default export is an object with an async `fetch(request, env)` method, in the sh...
Primitive Inbox API
Check inbound email setup and processing readiness
Primitive Memories API
Durable org-scoped or function-scoped JSON key-value storage for agents and functions. Keys are caller-defined. Function scope is always addressed by the function id UUID, not b...
Primitive Payments API
Collect and pay stablecoin (USDC) payments with x402. Settlement is non-custodial: funds move directly from payer to payee on-chain via an EIP-3009 authorization the payer signs...
Primitive Registries API
The Agent Registry: ownable directories of agents, addressable by a registry-scoped handle. A registry's publish policy (owner_only, request, or open) decides whether a publish ...
Primitive Routes API
Recipient routing: route inbound mail to a single destination per recipient address. Rules bind an address pattern (exact or wildcard) to an endpoint; `function_id` routes an ad...
Primitive Search API
Semantic and hybrid search across received and sent mail
Primitive Sending API
Send outbound emails through the Primitive API
Primitive Service API
Operational endpoints such as the unauthenticated health/liveness probe.
Primitive Templates API
Public Function template registry reads used to browse installable agent templates.
Primitive Threads API
Conversation threads spanning received and sent emails
Primitive Wake API
Wake scheduling: schedule and send typed wake commands to your own functions over real DKIM-signed email on a cron cadence, and manage the per-target allowlist that authorizes w...
Primitive Webhook Deliveries API
View and replay webhook delivery attempts
Scroll within the panel for all 22 ·
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
primitive-mcp.yml
MCP SERVEREvent 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.
Primitive Webhooks
ASYNCAPISecurity Posture 3
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 Primitive — 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 4
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 8
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 8 ·
Build 4
SDKs, sample code, and the tooling you integrate with
Access & Security 5
Authentication, authorization, and security posture
Operate 2
Status, limits, changes, and where to get help
Commercial 3
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
Other 1
Properties that don't map to a standard resource type
← All providers · Data indexed from github.com/api-evangelist/primitive · machine-readable index on apis.io