Sailthru is a cross-channel relationship-marketing and personalization platform built for media, publishing, retail and e-commerce brands, unifying email, SMS, mobile push, in-app and on-site messaging around a single customer profile with predictive segmentation and 1:1 content personalization. Founded in New York in 2008, it was acquired by CM Group (later Marigold) in 2018 and became part of Zeta Global in November 2025 when Zeta bought Marigold's enterprise software business; the product is now documented as Sailthru by Zeta. Its public HTTPS API lives at api.sailthru.com and covers users, lists, content, templates, blasts (campaigns), transactional sends, triggers, purchases, events, includes, ad plans and stats, authenticated with an api_key plus an MD5 signature computed over the request parameters. It is complemented by the Zephyr template language, a JavaScript on-site personalization tag, mobile SDKs, and API postbacks (webhooks) for opt-out, hardbounce, verify and profile-update events.
Sailthru publishes 2 APIs on the APIs.io network. Tagged areas include Company, Email Marketing, Marketing Automation, Personalization, and Customer Data Platform.
The Sailthru catalog on APIs.io includes 1 event-driven AsyncAPI specification.
Sailthru’s developer surface includes documentation, API reference, getting-started guide, support, engineering blog, signup flow, changelog, and 24 more developer resources.
Regulatory Posture applies to this provider. Its tags matched the
Telecommunications regime, so
Regulatory Posture carries 15 points of the composite.
If this regime is wrong for your business, say so on your
provider repo — the
applicability map is public and we will correct it.
The six quality facets above are damped to 85 points between them,
because the conditional facet above carries the other
15. That is why each facet's contribution is shown against a damped
maximum: raising a quality facet moves the composite by 85% of its nominal
weight, not 100%. The full arithmetic is at apis.io/rating/.
The core Sailthru HTTPS API. All requests are GET, POST or DELETE calls to https://api.sailthru.com/, authenticated with api_key, an MD5 sig over the sorted parame...
The client-side Sailthru JavaScript tag (spm.v1.min.js, served from ak.sail-horizon.com) used for on-site behavior tracking, content-library sync, userSignUp/userSignUpConfirm c...
aid: sailthru
name: Sailthru
description: Sailthru is a cross-channel relationship-marketing and personalization platform built for media, publishing,
retail and e-commerce brands, unifying email, SMS, mobile push, in-app and on-site messaging around a single customer profile
with predictive segmentation and 1:1 content personalization. Founded in New York in 2008, it was acquired by CM Group (later
Marigold) in 2018 and became part of Zeta Global in November 2025 when Zeta bought Marigold's enterprise software business;
the product is now documented as Sailthru by Zeta. Its public HTTPS API lives at api.sailthru.com and covers users, lists,
content, templates, blasts (campaigns), transactional sends, triggers, purchases, events, includes, ad plans and stats,
authenticated with an api_key plus an MD5 signature computed over the request parameters. It is complemented by the Zephyr
template language, a JavaScript on-site personalization tag, mobile SDKs, and API postbacks (webhooks) for opt-out, hardbounce,
verify and profile-update events.
image: https://zetaglobal.com/wp-content/uploads/2025/12/ZetaMarigold-Landing-page-images-09-1.png
url: https://raw.githubusercontent.com/api-evangelist/sailthru/refs/heads/main/apis.yml
x-type: company
x-source: harvest:marketing-integration-graph
x-tier: profiled
x-tier-reason: enrichment
x-parent-company: 'Zeta Global Holdings Corp. (NYSE: ZETA)'
specificationVersion: '0.20'
created: '2026-08-12'
modified: '2026-08-12'
tags:
- Company
- Email Marketing
- Marketing Automation
- Personalization
- Customer Data Platform
- Transactional Email
- SMS
- Push Notifications
- Retail
- Media and Publishing
apis:
- aid: sailthru:sailthru-api
name: Sailthru API
description: The core Sailthru HTTPS API. All requests are GET, POST or DELETE calls to https://api.sailthru.com/<endpointName>,
authenticated with api_key, an MD5 sig over the sorted parameter values, and a format parameter (json or xml). Endpoints
cover user profiles, lists, content, templates, blasts (campaigns), transactional send, trigger, purchase, event, include,
ad-plan, preview, settings, stats and bulk job operations.
humanURL: https://products.zetaglobal.com/sailthru/Content/developers/api-basics/introduction.html
baseURL: https://api.sailthru.com
tags:
- Email Marketing
- Transactional Email
- Marketing Automation
- Personalization
properties:
- type: Documentation
url: https://products.zetaglobal.com/sailthru/Content/developers/overview.html
- type: APIReference
url: https://products.zetaglobal.com/sailthru/Content/developers/api-basics/introduction.html
- type: GettingStarted
url: https://products.zetaglobal.com/sailthru/Content/developers/api-basics/technical.html
- type: Authentication
url: authentication/sailthru-authentication.yml
- type: RateLimits
url: rate-limits/sailthru-rate-limits.yml
- type: ErrorCatalog
url: errors/sailthru-error-codes.yml
- type: Conventions
url: conventions/sailthru-conventions.yml
- type: Webhooks
url: asyncapi/sailthru-postbacks-webhooks.yml
- aid: sailthru:sailthru-js-api
name: Sailthru JavaScript API (Personalization Engine)
description: The client-side Sailthru JavaScript tag (spm.v1.min.js, served from ak.sail-horizon.com) used for on-site behavior
tracking, content-library sync, userSignUp/userSignUpConfirm calls and on-site personalization. It is the browser counterpart
to the server-side API and is loaded as a script rather than called over REST.
humanURL: https://products.zetaglobal.com/sailthru/Content/developers/api-client/javascript.html
baseURL: https://ak.sail-horizon.com
tags:
- Personalization
- JavaScript
- Web
properties:
- type: Documentation
url: https://products.zetaglobal.com/sailthru/Content/developers/api-client/javascript.html
maintainers:
- FN: Kin Lane
email: kin@apievangelist.com
- FN: APIs.json
email: info@apis.io
common:
- type: TrustCenter
url: security/sailthru-trust-center.yml
- type: DomainSecurity
url: security/sailthru-domain-security.yml
- type: VulnerabilityDisclosure
url: security/sailthru-vulnerability-disclosure.yml
- type: Security
url: https://bugcrowd.com/engagements/cheetah-vdp
- type: Compliance
url: https://trust.zetaglobal.com/?product=sailthru
- type: Website
url: https://zetaglobal.com/sailthru/
- type: DeveloperPortal
url: https://products.zetaglobal.com/sailthru/Content/developers/overview.html
- type: Documentation
url: https://products.zetaglobal.com/sailthru/Content/LandingPage.htm
- type: APIReference
url: https://products.zetaglobal.com/sailthru/Content/developers/api-basics/introduction.html
- type: GettingStarted
url: https://products.zetaglobal.com/sailthru/Content/developers/api-basics/technical.html
- type: Support
url: https://zetaglobal.com/about/contact-us/
- type: Blog
url: https://zetaglobal.com/resource-center/
- type: GitHubOrganization
url: https://github.com/sailthru
- type: SignUp
url: https://my.sailthru.com/
- type: TermsOfService
url: https://zetaglobal.com/former-marigold-now-zeta-services-agreement/
- type: PrivacyPolicy
url: https://zetaglobal.com/privacy-policy
- type: ChangeLog
url: https://products.zetaglobal.com/sailthru/Content/ReleaseNotes/releasenotes-2026.htm
- type: ChangeLog
url: changelog/sailthru-changelog.yml
- type: Packages
url: packages/sailthru-packages.yml
- type: SDKs
url: packages/sailthru-packages.yml
- type: CLI
url: cli/sailthru-cli.yml
- type: Components
url: components/sailthru-components.yml
- type: Authentication
url: authentication/sailthru-authentication.yml
- type: Conventions
url: conventions/sailthru-conventions.yml
- type: ErrorCatalog
url: errors/sailthru-error-codes.yml
- type: RateLimits
url: rate-limits/sailthru-rate-limits.yml
- type: Plans
url: plans/sailthru-plans-pricing.yml
- type: Lifecycle
url: lifecycle/sailthru-lifecycle.yml
- type: Conformance
url: conformance/sailthru-conformance.yml
- type: Webhooks
url: asyncapi/sailthru-postbacks-webhooks.yml
- type: LLMsTxt
url: llms/sailthru-llms.txt
x-enrichment:
date: '2026-08-12'
status: enriched
artifacts_added: 17
pass: local-v1
x-coverage:
state: covered
reason: null
detail: Documentation is public, server-rendered and fully readable at products.zetaglobal.com/sailthru; seventeen artifacts
were harvested from it and from live probes. The one genuine gap is machine-readable contract — Sailthru publishes no
OpenAPI, AsyncAPI, GraphQL, MCP or /.well-known/ surface anywhere.
checked: '2026-08-12'
x-vouched-by:
- Lytics
- Persado
- Simon Data
- mParticle
x-vouch-count: 4
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