Loops

Loops is an email platform built for software companies, combining marketing campaigns, product and lifecycle automation, and transactional email on one contact model. Its REST API v1 exposes 64 operations across contacts, contact properties, mailing lists, audience segments, events and event patterns, campaigns, transactional emails, email messages authored in its own LMX markup, themes, components, uploads and workflow graphs, plus a 17-event signed webhook surface. Loops publishes its OpenAPI 3.1 document openly, ships first-party SDKs for JavaScript, Go, PHP, Ruby and Nuxt, a Go CLI, four versioned Agent Skills, and a hosted OAuth-protected MCP server at mcp.loops.so. Pricing is based on stored subscribed contacts rather than send volume, with a permanent free tier. The operating company is Astrodon Corporation.

Loops publishes 19 APIs on the APIs.io network, including API key API, Audience segments API, Campaign groups API, and 16 more. Tagged areas include Email, Email API, Marketing Automation, Transactional Email, and Lifecycle Email.

The Loops catalog on APIs.io includes 1 event-driven AsyncAPI specification.

Loops’ developer surface includes authentication, code examples, CLI, changelog, documentation, API reference, getting-started guide, and 38 more developer resources.

🌐 Visit website 📡 Source on GitHub

72.0/100 exemplar ▬ flat Agent 60/100 agent native Full breakdown ↓
scored 2026-08-20 · rubric v0.12.0

AccessFreemiumSelf serve⚡ Free to try

20 APIs 1 MCP Servers

Email Email API Marketing Automation Transactional EmailLifecycle EmailWebhook Software-as-a-Service Communications Developer Tools MCP Agents Campaigns

Kin Score

Kin Score How this is scored →
scored 2026-08-20 · rubric v0.12.0

Composite quality — 72.0/100 · exemplar

Contract Quality 16.0 / 25

Developer Ergonomics 15.7 / 20

Access Clarity 17.9 / 20

Operational Transparency 9.6 / 13

Contract Governance 3.6 / 12

Discoverability 9.3 / 10

Agent readiness — 60/100 · agent native

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 12 / 12

Machine-Readable Auth 10 / 10

Idempotency 9 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 6 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/loops: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 20

Individual APIs this provider publishes, each with its own machine-readable definition.

Open Collections 12

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

MCP Servers 1

Model Context Protocol servers that expose these APIs to AI agents.

Rate Limits 1

Documented rate limits and quota policies.

Loops Rate Limits

8 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Scopes 1

OAuth scopes governing access to this provider's APIs.

Loops Scopes

OAuth 2.0 · no documented scopes

0 scopes

SCOPES

Get Started 5

Portal, sign-up, and the first successful call

DeveloperPortal

GettingStarted

Quickstart

SignUp

Login

Documentation 3

Reference material describing how the API behaves

AsyncAPI

AsyncAPI

Documentation

Documentation

APIReference

APIReference

Agent Surfaces 5

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

MCPServer

AgentSkill

WellKnown

LLMsTxt

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Conventions

Idempotency

ErrorCatalog

DataModel

Webhooks

Lifecycle

Conformance

Scroll for all 7

Build 6

SDKs, sample code, and the tooling you integrate with

Examples

Packages

SDKs

CLI

ToolCrosswalk

GitHubOrganization

GitHubOrganization

Access & Security 5

Authentication, authorization, and security posture

Authentication

OAuthScopes

Compliance

TrustCenter

DomainSecurity

Operate 4

Status, limits, changes, and where to get help

RateLimits

StatusPage

ChangeLog

Support

Commercial 6

Pricing, plans, and the legal terms of use

Plans

FinOps

Pricing

TermsOfService

PrivacyPolicy

DataProcessingAgreement

DataProcessingAgreement

Company 3

The organization behind the API

Website

Website

Blog

Blog

LinkedIn

Other 1

Properties that don't map to a standard resource type

Glossary

Glossary

Source (apis.yml)

aid: loops
url: https://raw.githubusercontent.com/api-evangelist/loops/refs/heads/main/apis.yml
name: Loops
kind: company
description: Loops is an email platform built for software companies, combining marketing campaigns, product and lifecycle
  automation, and transactional email on one contact model. Its REST API v1 exposes 64 operations across contacts, contact
  properties, mailing lists, audience segments, events and event patterns, campaigns, transactional emails, email messages
  authored in its own LMX markup, themes, components, uploads and workflow graphs, plus a 17-event signed webhook surface.
  Loops publishes its OpenAPI 3.1 document openly, ships first-party SDKs for JavaScript, Go, PHP, Ruby and Nuxt, a Go CLI,
  four versioned Agent Skills, and a hosted OAuth-protected MCP server at mcp.loops.so. Pricing is based on stored subscribed
  contacts rather than send volume, with a permanent free tier. The operating company is Astrodon Corporation.
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: true
  label: Free plan, self-serve signup
  confidence: high
  source:
  - https://loops.so/pricing
  - https://loops.so/docs/api-reference/intro
  generated: '2026-08-13'
  method: searched
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/loops.png
tags:
- Email
- Email API
- Marketing Automation
- Transactional Email
- Lifecycle Email
- Webhook
- Software-as-a-Service
- Communications
- Developer Tools
- MCP
- Agents
- Campaigns
tags_raw:
- Email
- Email API
- Marketing Automation
- Transactional Email
- Lifecycle Email
- Webhooks
- SaaS
- Communications
- Developer Tools
- MCP
- Agents
- Campaigns
created: '2026-05-08'
modified: '2026-08-13'
specificationVersion: '0.23'
apis:
- aid: loops:loops-api-key-api
  name: Loops API key API
  description: Validate a Loops API key and discover which team it belongs to. 1 operation(s) in the Loops REST API v1 (OpenAPI
    1.21.6).
  humanURL: https://loops.so/docs/api-reference/api-key
  baseURL: https://app.loops.so/api/v1
  tags:
  - APIKeys
  tags_raw:
  - API key
  properties:
  - type: OpenAPI
    url: openapi/loops-api-key-api-openapi.yml
  - type: Overlay
    url: overlays/loops-api-key-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/api-key
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-audience-segments-api
  name: Loops Audience segments API
  description: Read and create saved audience segments used to target campaigns and workflows. 3 operation(s) in the Loops
    REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-audience-segments
  baseURL: https://app.loops.so/api/v1
  tags:
  - Audience Segments
  tags_raw:
  - Audience segments
  properties:
  - type: OpenAPI
    url: openapi/loops-audience-segments-api-openapi.yml
  - type: Overlay
    url: overlays/loops-audience-segments-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-audience-segments
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-campaign-groups-api
  name: Loops Campaign groups API
  description: Organize campaigns into groups. 4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-campaign-groups
  baseURL: https://app.loops.so/api/v1
  tags:
  - Campaign groups
  properties:
  - type: OpenAPI
    url: openapi/loops-campaign-groups-api-openapi.yml
  - type: Overlay
    url: overlays/loops-campaign-groups-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-campaign-groups
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-campaigns-api
  name: Loops Campaigns API
  description: Create, target, schedule and update email campaigns. 4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-campaigns
  baseURL: https://app.loops.so/api/v1
  tags:
  - Campaigns
  properties:
  - type: OpenAPI
    url: openapi/loops-campaigns-api-openapi.yml
  - type: Overlay
    url: overlays/loops-campaigns-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-campaigns
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-components-api
  name: Loops Components API
  description: Create, read and update reusable LMX email components. 4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-components
  baseURL: https://app.loops.so/api/v1
  tags:
  - Components
  properties:
  - type: OpenAPI
    url: openapi/loops-components-api-openapi.yml
  - type: Overlay
    url: overlays/loops-components-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-components
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-configuration-api
  name: Loops Configuration API
  description: Read team configuration, including dedicated sending IP addresses. 1 operation(s) in the Loops REST API v1
    (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/dedicated-sending-ips
  baseURL: https://app.loops.so/api/v1
  tags:
  - Configuration
  properties:
  - type: OpenAPI
    url: openapi/loops-configuration-api-openapi.yml
  - type: Overlay
    url: overlays/loops-configuration-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/dedicated-sending-ips
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-contact-properties-api
  name: Loops Contact properties API
  description: Create and list the custom properties available on contacts. 2 operation(s) in the Loops REST API v1 (OpenAPI
    1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-contact-properties
  baseURL: https://app.loops.so/api/v1
  tags:
  - Contact properties
  properties:
  - type: OpenAPI
    url: openapi/loops-contact-properties-api-openapi.yml
  - type: Overlay
    url: overlays/loops-contact-properties-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-contact-properties
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-contacts-api
  name: Loops Contacts API
  description: Create, update, find and delete contacts, and manage suppression status. 6 operation(s) in the Loops REST API
    v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/create-contact
  baseURL: https://app.loops.so/api/v1
  tags:
  - Contacts
  properties:
  - type: OpenAPI
    url: openapi/loops-contacts-api-openapi.yml
  - type: Overlay
    url: overlays/loops-contacts-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/create-contact
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-email-messages-api
  name: Loops Email messages API
  description: Read, update, preview and Guardian-validate the LMX body of campaigns, workflow emails and transactional templates.
    4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/get-email-message
  baseURL: https://app.loops.so/api/v1
  tags:
  - Email messages
  properties:
  - type: OpenAPI
    url: openapi/loops-email-messages-api-openapi.yml
  - type: Overlay
    url: overlays/loops-email-messages-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/get-email-message
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-event-patterns-api
  name: Loops Event patterns API
  description: Read the event patterns Loops has detected from incoming events, including their observed properties. 3 operation(s)
    in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-event-patterns
  baseURL: https://app.loops.so/api/v1
  tags:
  - Event patterns
  properties:
  - type: OpenAPI
    url: openapi/loops-event-patterns-api-openapi.yml
  - type: Overlay
    url: overlays/loops-event-patterns-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-event-patterns
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-events-api
  name: Loops Events API
  description: Send events that update contact activity and trigger published workflows. 1 operation(s) in the Loops REST
    API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/send-event
  baseURL: https://app.loops.so/api/v1
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/loops-events-api-openapi.yml
  - type: Overlay
    url: overlays/loops-events-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/send-event
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-mailing-lists-api
  name: Loops Mailing lists API
  description: List the mailing lists in your account. 1 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-mailing-lists
  baseURL: https://app.loops.so/api/v1
  tags:
  - Mailing Lists
  tags_raw:
  - Mailing lists
  properties:
  - type: OpenAPI
    url: openapi/loops-mailing-lists-api-openapi.yml
  - type: Overlay
    url: overlays/loops-mailing-lists-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-mailing-lists
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-themes-api
  name: Loops Themes API
  description: Create, read and update reusable email themes. 4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-themes
  baseURL: https://app.loops.so/api/v1
  tags:
  - Themes
  properties:
  - type: OpenAPI
    url: openapi/loops-themes-api-openapi.yml
  - type: Overlay
    url: overlays/loops-themes-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-themes
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-transactional-emails-api
  name: Loops Transactional emails API
  description: Create, edit, publish, list and send transactional email templates with data variables. 8 operation(s) in the
    Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/send-transactional-email
  baseURL: https://app.loops.so/api/v1
  tags:
  - Transactional Emails
  tags_raw:
  - Transactional emails
  properties:
  - type: OpenAPI
    url: openapi/loops-transactional-emails-api-openapi.yml
  - type: Overlay
    url: overlays/loops-transactional-emails-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/send-transactional-email
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-transactional-groups-api
  name: Loops Transactional groups API
  description: Organize transactional emails into groups. 4 operation(s) in the Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-transactional-groups
  baseURL: https://app.loops.so/api/v1
  tags:
  - Transactional groups
  properties:
  - type: OpenAPI
    url: openapi/loops-transactional-groups-api-openapi.yml
  - type: Overlay
    url: overlays/loops-transactional-groups-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-transactional-groups
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-uploads-api
  name: Loops Uploads API
  description: Upload image assets for use in emails via a presigned-URL flow. 2 operation(s) in the Loops REST API v1 (OpenAPI
    1.21.6).
  humanURL: https://loops.so/docs/api-reference/create-upload
  baseURL: https://app.loops.so/api/v1
  tags:
  - Uploads
  properties:
  - type: OpenAPI
    url: openapi/loops-uploads-api-openapi.yml
  - type: Overlay
    url: overlays/loops-uploads-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/create-upload
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-workflow-nodes-api
  name: Loops Workflow nodes API
  description: Create, read, update, delete and reroute the nodes of a workflow graph. 7 operation(s) in the Loops REST API
    v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/get-workflow-node
  baseURL: https://app.loops.so/api/v1
  tags:
  - Workflow nodes
  properties:
  - type: OpenAPI
    url: openapi/loops-workflow-nodes-api-openapi.yml
  - type: Overlay
    url: overlays/loops-workflow-nodes-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/get-workflow-node
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-workflows-api
  name: Loops Workflows API
  description: List, create, inspect and update automation workflows and their mailing-list targeting. 5 operation(s) in the
    Loops REST API v1 (OpenAPI 1.21.6).
  humanURL: https://loops.so/docs/api-reference/list-workflows
  baseURL: https://app.loops.so/api/v1
  tags:
  - Workflows
  properties:
  - type: OpenAPI
    url: openapi/loops-workflows-api-openapi.yml
  - type: Overlay
    url: overlays/loops-workflows-overlay.yaml
  - type: Documentation
    url: https://loops.so/docs/api-reference/list-workflows
  - type: APIReference
    url: https://loops.so/docs/api-reference/intro
- aid: loops:loops-mcp-server
  name: Loops MCP Server
  description: Remote Model Context Protocol server for Loops, reachable at https://mcp.loops.so over Streamable HTTP with
    OAuth 2.0 (PKCE, scope "mcp"). Exposes four meta-tools — search, describe, execute and teams — that let an agent discover
    and run any operation in the Loops REST API for any team the signed-in user can access.
  humanURL: https://loops.so/docs/mcp-server
  baseURL: https://mcp.loops.so
  tags:
  - MCP
  - Agents
  - Email
  properties:
  - type: MCPServer
    url: mcp/loops-mcp.yml
  - type: ToolCrosswalk
    url: mcp/loops-tool-crosswalk.yml
  - type: OAuthScopes
    url: scopes/loops-scopes.yml
  - type: Documentation
    url: https://loops.so/docs/mcp-server
- aid: loops:loops-webhooks
  name: Loops Webhooks
  description: Outbound event surface. Seventeen signed event types covering contact lifecycle, mailing-list membership, and
    email delivery, engagement and complaint signals, delivered by HTTP POST to one subscriber-configured endpoint per account
    and verified with an HMAC-SHA256 signature over {webhook-id}.{webhook-timestamp}.{raw-body}.
  humanURL: https://loops.so/docs/webhooks
  baseURL: https://app.loops.so/api/v1
  tags:
  - Webhook
  - Event
  - Email
  tags_raw:
  - Webhooks
  - Events
  - Email
  properties:
  - type: AsyncAPI
    url: asyncapi/loops-webhooks-asyncapi.yml
  - type: Webhooks
    url: asyncapi/loops-webhooks-asyncapi.yml
  - type: Documentation
    url: https://loops.so/docs/webhooks
common:
- type: AgenticAccess
  url: agentic-access/loops-agentic-access.yml
- type: Authentication
  url: authentication/loops-authentication.yml
- type: OAuthScopes
  url: scopes/loops-scopes.yml
- type: Conventions
  url: conventions/loops-conventions.yml
- type: Idempotency
  url: conventions/loops-conventions.yml
- type: ErrorCatalog
  url: errors/loops-problem-types.yml
- type: RateLimits
  url: rate-limits/loops-rate-limits.yml
- type: Plans
  url: plans/loops-plans-pricing.yml
- type: FinOps
  url: finops/loops-finops.yml
- type: DataModel
  url: data-model/loops-data-model.yml
- type: Examples
  url: examples/loops-examples.yml
- type: Packages
  url: packages/loops-packages.yml
- type: SDKs
  url: packages/loops-packages.yml
- type: CLI
  url: cli/loops-cli.yml
- type: MCPServer
  url: mcp/loops-mcp.yml
- type: ToolCrosswalk
  url: mcp/loops-tool-crosswalk.yml
- type: AgentSkill
  url: skills/_index.yml
- type: AsyncAPI
  url: asyncapi/loops-webhooks-asyncapi.yml
- type: Webhooks
  url: asyncapi/loops-webhooks-asyncapi.yml
- type: WellKnown
  url: well-known/loops-well-known.yml
- type: Lifecycle
  url: lifecycle/loops-lifecycle.yml
- type: StatusPage
  url: https://status.loops.so
- type: ChangeLog
  url: changelog/loops-changelog.yml
- type: Conformance
  url: conformance/loops-conformance.yml
- type: Compliance
  url: conformance/loops-conformance.yml
- type: TrustCenter
  url: security/loops-trust-center.yml
- type: DomainSecurity
  url: security/loops-domain-security.yml
- type: LLMsTxt
  url: llms/loops-llms.txt
- type: Website
  url: https://loops.so/
- type: DeveloperPortal
  url: https://loops.so/docs
- type: Documentation
  url: https://loops.so/docs
- type: APIReference
  url: https://loops.so/docs/api-reference/intro
- type: GettingStarted
  url: https://loops.so/docs/quickstart
- type: Quickstart
  url: https://loops.so/docs/quickstart-agents
- type: Support
  url: https://app.loops.so/settings?page=support
- type: Blog
  url: https://loops.so/engineering
- type: GitHubOrganization
  url: https://github.com/Loops-so
- type: Pricing
  url: https://loops.so/pricing
- type: SignUp
  url: https://app.loops.so/register
- type: Login
  url: https://app.loops.so/
- type: TermsOfService
  url: https://loops.so/terms
- type: PrivacyPolicy
  url: https://loops.so/privacy
- type: DataProcessingAgreement
  url: https://loops.so/dpa
- type: LinkedIn
  url: https://www.linkedin.com/company/sendwithloops
- type: Integrations
  url: https://loops.so/docs/integrations
- type: Glossary
  url: https://loops.so/glossary
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
x-enrichment:
  date: '2026-08-13'
  status: enriched
  artifacts_added: 49
  pass: local-v1