TellApart

TellApart was a predictive-marketing and cross-device retargeting technology company founded in 2009 by former Google AdWords-API engineers Josh McFarland and Mark Ayzenshtat. Its cloud-based customer data platform unified shopper profiles across channels and devices and used machine-learning scoring to power dynamic product ads and direct-response retargeting for retailers such as Neiman Marcus, Wayfair, Sur La Table and Pottery Barn. TellApart was acquired by Twitter in April 2015 for roughly $533M in stock and folded into Twitter's advertising business; it no longer operates as an independent company and the tellapart.com domain is now parked with no live developer or API surface. Surfaced as a Greylock portfolio company and added to the API Evangelist network as a stub for enrichment.

TellApart is profiled on the APIs.io network. Tagged areas include Company, Applications, Advertising, Marketing, and Retargeting.

🌐 Visit website 📡 Source on GitHub
6.8/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-07-27 · rubric v0.5
0 APIs
CompanyApplicationsAdvertisingMarketingRetargetingMachine LearningCustomer Data PlatformAcquired

Kin Score

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scored 2026-07-27 · rubric v0.5
Composite quality — 6.8/100 · minimal
Contract Quality 0.0 / 25
Developer Ergonomics 0.0 / 20
Commercial Clarity 0.0 / 20
Operational Transparency 0.0 / 13
Governance 0.0 / 12
Discoverability 6.8 / 10
Agent readiness — 0/100 · human only
Machine-Readable Contract 0 / 18
Agentic Access Contract 0 / 15
MCP Server 0 / 12
Machine-Readable Auth 0 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 0 / 7
Rate-Limit Signaling 0 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
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/tellapart: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

Resources

Company 1

The organization behind the API

Website
Website

Source (apis.yml)

apis.yml Raw ↑ 
aid: tellapart
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source: []
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/tellapart.png
name: TellApart
description: TellApart was a predictive-marketing and cross-device retargeting technology company founded in 2009 by former
  Google AdWords-API engineers Josh McFarland and Mark Ayzenshtat. Its cloud-based customer data platform unified shopper
  profiles across channels and devices and used machine-learning scoring to power dynamic product ads and direct-response
  retargeting for retailers such as Neiman Marcus, Wayfair, Sur La Table and Pottery Barn. TellApart was acquired by Twitter
  in April 2015 for roughly $533M in stock and folded into Twitter's advertising business; it no longer operates as an independent
  company and the tellapart.com domain is now parked with no live developer or API surface. Surfaced as a Greylock portfolio
  company and added to the API Evangelist network as a stub for enrichment.
url: https://raw.githubusercontent.com/api-evangelist/tellapart/refs/heads/main/apis.yml
x-type: company
x-source: vc-portfolio
x-backed-by:
- greylock
x-tier: stub
x-tier-reason: portfolio-lead
x-status: defunct
x-acquired-by: twitter
x-acquired-date: 2015-04
x-acquired-amount-usd: 533000000
specificationVersion: '0.20'
created: '2026-07-17'
modified: '2026-07-21'
tags:
- Company
- Applications
- Advertising
- Marketing
- Retargeting
- Machine Learning
- Customer Data Platform
- Acquired
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://tellapart.com
x-enrichment:
  date: '2026-07-21'
  status: nochange
  artifacts_added: 0
  pass: local-v1