# MarketSizer - Full Technical Reference for LLMs

  > This document provides comprehensive technical detail about MarketSizer's platform, API, data model, and integration capabilities.

  ## Platform Overview

  MarketSizer is a subscription intelligence platform for B2B SaaS go-to-market teams. It monitors real-time SaaS subscription changes (trials,
  upgrades, downgrades, cancellations, competitive switches) across 50M+ companies and 200+ tracked vendors, then scores accounts using a
  proprietary Opportunity Score combining:

  1. **ICP Match** - Behavioural fit based on subscription patterns, tech stack composition, and historical win data (not just firmographic
  attributes)
  2. **Purchase Intent** - Active buying signals from subscription changes, trial starts, vendor evaluations
  3. **Win Probability** - Likelihood of conversion calculated from 70M+ historical subscription outcomes

  ### Data Scale
 - 50M+ companies tracked globally
 - 17M+ active subscriptions monitored
 - 200+ SaaS vendors with trial detection
 - 70M+ historical subscription outcomes for win probability
 - Daily refresh cycle from BigQuery

  ### Key Differentiation
  MarketSizer uses **actual subscription transaction data** as its signal source. Most intent data providers (Bombora, 6sense, TechTarget) rely on
  anonymous web visit aggregation or keyword co-occurrence, which measures _research interest_ but not _buying action_. MarketSizer detects when a
  company literally starts a trial, switches vendors, or cancels a subscription - a fundamentally different signal.

  ---

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## Key Pages

Top-level entry points on https://www.marketsizer.io for orientation:

 - [Platform](https://www.marketsizer.io/platform): How MarketSizer surfaces qualified B2B accounts ranked by Purchase Intent, ICP Fit, and Win Probability.
 - [Our Data](https://www.marketsizer.io/our-data): The live data behind every opportunity, refreshed daily.
 - [Integrations](https://www.marketsizer.io/integrations): Native connections to HubSpot, Pipedrive, Zoho CRM, Instantly, Brevo, Gmail, Google Sheets, Google Calendar, Slack and Microsoft Teams, plus a public API, webhooks and CSV import/export.
 - [Compare](https://www.marketsizer.io/compare): How MarketSizer works alongside tools like Apollo and Clay, and how it compares head-to-head with ZoomInfo, 6sense, Bombora and HG Insights.
 - [Features](https://www.marketsizer.io/features): Index of feature pages.
 - [Solutions](https://www.marketsizer.io/solutions): Role and vertical solutions for sales, marketing, RevOps, CS, CRM, ITSM, CX, lead-gen agencies, and SaaS vendors.
 - [Pricing](https://www.marketsizer.io/pricing): Credit-based pricing with a free trial and no per-seat multiplier.
 - [FAQ](https://www.marketsizer.io/faq): Product, data, pricing, integrations, and security FAQs.
 - [Blog](https://www.marketsizer.io/blog): Articles on subscription intelligence, GTM timing, and signal-based selling.
 - [Book a Demo](https://www.marketsizer.io/book-a-demo): Live Opportunity Scores on your own accounts in a 30-minute call.
 - [Full content for LLMs](https://www.marketsizer.io/llms-full.txt): Generated extract of every marketing page, feature, solution, blog post, and FAQ.

---

## Comparison Pages

Tools MarketSizer works alongside (different job, no budget overlap):

 - [MarketSizer & Amplemarket](https://www.marketsizer.io/compare/amplemarket): How MarketSizer works with Amplemarket: what each does well on AI outbound and buying signals, where they differ, and how teams run them together.
 - [MarketSizer & Apollo](https://www.marketsizer.io/compare/apollo): How MarketSizer works with Apollo: what each tool does well, where they differ on contact data, buying signals and pricing, and how teams run them together.
 - [MarketSizer & BuiltWith](https://www.marketsizer.io/compare/builtwith): MarketSizer and BuiltWith do different jobs: technographic breadth versus subscription-timing signals. What each is best at, and how teams run both.
 - [MarketSizer & Clay](https://www.marketsizer.io/compare/clay): How MarketSizer works with Clay: what each tool does well, where they differ on enrichment, buying signals and workflow, and how teams run them together.
 - [MarketSizer & Cognism](https://www.marketsizer.io/compare/cognism): How MarketSizer works with Cognism: what each does well on contact data, compliance and buying signals, and how teams layer them in one workflow.
 - [MarketSizer & Lusha](https://www.marketsizer.io/compare/lusha): How MarketSizer works with Lusha: what each does well on contact data, buying signals and pricing, and how teams layer them in one workflow.
 - [MarketSizer & RB2B](https://www.marketsizer.io/compare/rb2b): How MarketSizer works with RB2B: person-level visitor identification plus market-level buying signals, and how teams layer the two into one pipeline.
 - [MarketSizer & Wappalyzer](https://www.marketsizer.io/compare/wappalyzer): MarketSizer and Wappalyzer do different jobs: instant tech-stack lookups versus subscription-timing signals. What each is best at, and how teams use both.

Tools MarketSizer competes with directly:

 - [MarketSizer vs 6sense](https://www.marketsizer.io/compare/6sense): MarketSizer vs 6sense compared on intent signals, workflow, pricing and setup. Where each is strong, when to choose 6sense, and how teams layer them.
 - [MarketSizer vs Bloomberry](https://www.marketsizer.io/compare/bloomberry): MarketSizer vs Bloomberry compared on tech-stack signals, category depth, workflow and pricing. Where each is strong and how to choose.
 - [MarketSizer vs Bombora](https://www.marketsizer.io/compare/bombora): MarketSizer vs Bombora compared on intent signal source, workflow, latency and pricing. Where each is strong and how teams layer them.
 - [MarketSizer vs Common Room](https://www.marketsizer.io/compare/common-room): MarketSizer vs Common Room compared on signal aggregation, workflow, pricing and category fit. Where each is strong and how they layer.
 - [MarketSizer vs HG Insights](https://www.marketsizer.io/compare/hg-insights): MarketSizer vs HG Insights compared on technographic depth, buying signals, workflow and pricing. Where each is strong, when to choose HG, and how teams layer them.
 - [MarketSizer vs PredictLeads](https://www.marketsizer.io/compare/predictleads): MarketSizer vs PredictLeads compared on event-based signals, workflow, pricing and category depth. Where each is strong and how they layer.
 - [MarketSizer vs Warmly](https://www.marketsizer.io/compare/warmly): MarketSizer vs Warmly compared on visitor identification, buying signals, workflow and pricing. Where each is strong and how they layer.
 - [MarketSizer vs ZoomInfo](https://www.marketsizer.io/compare/zoominfo): MarketSizer vs ZoomInfo compared on contact data, intent signals, setup, pricing and workflow. Where each is strong, when to choose ZoomInfo, and how teams layer them.

---

## Feature Pages

 - [ACV Estimates](https://www.marketsizer.io/features/acv-estimates): ACV Estimates gives your team account-level contract value projections before the first call - so reps prioritise by revenue opportunity, not just ICP fit.
 - [AI Agents](https://www.marketsizer.io/features/ai-agents): Use MarketSizer account intelligence directly in Claude, Cursor, and other AI tools. Ask any AI agent to qualify an account, surface intent signals, or check ICP fit - live data, no exports.
 - [Chrome Extension](https://www.marketsizer.io/features/chrome-extension): Copilot is a Chrome extension that surfaces MarketSizer account intelligence as a sidebar on LinkedIn, your CRM, and any website - Opportunity Score, ICP fit, and subscription signals without switching tabs.
 - [ICP Scoring](https://www.marketsizer.io/features/icp-scoring): ICP Scoring matches every account in your addressable market against your ideal customer profile in real time - so reps only work accounts worth working.
 - [Lead Qualification](https://www.marketsizer.io/features/lead-qualification): Lead Qualification overlays real-time ICP fit, purchase intent, and win likelihood onto every inbound lead the moment it arrives - so reps only work leads worth working.
 - [Market Intelligence](https://www.marketsizer.io/features/market-intelligence): Market Intelligence gives you a live view of evaluation activity, vendor movements, and buying patterns across your total addressable market - before it shows up in analyst reports.
 - [Opportunity Discovery](https://www.marketsizer.io/features/opportunity-discovery): Opportunity Discovery gives your team a daily ranked feed of accounts that fit your ICP, are actively evaluating, and are historically winnable.
 - [Purchase Intent](https://www.marketsizer.io/features/purchase-intent): Evaluation Signals detect real-time buying activity and switching propensity across your addressable market - so you reach buyers the moment they start looking.
 - [Retention and Expansion](https://www.marketsizer.io/features/retention-and-expansion): Retention and Expansion monitors your customer base for early churn risk and expansion readiness - so your CS team acts before the situation becomes irreversible.
 - [Win Likelihood](https://www.marketsizer.io/features/win-likelihood): Win Likelihood scores every account against 70M+ historical deal outcomes to give your team a real probability of winning - by scenario, competitor, and deal size.
 - [Winback Opportunities](https://www.marketsizer.io/features/winback-opportunities): Winback Opportunities identifies former customers who are back in an active evaluation cycle - ranked by win likelihood and time to decision, so you get there before a competitor does.

---

## Solution Pages

 - [CRM](https://www.marketsizer.io/solutions/crm)
 - [Customer Success Teams](https://www.marketsizer.io/solutions/customer-success-teams)
 - [CX Live Chat](https://www.marketsizer.io/solutions/cx-live-chat)
 - [Enterprise](https://www.marketsizer.io/solutions/enterprise)
 - [Implementation Partners](https://www.marketsizer.io/solutions/implementation-partners)
 - [ITSM](https://www.marketsizer.io/solutions/itsm)
 - [Lead Gen Agencies](https://www.marketsizer.io/solutions/lead-gen-agencies)
 - [Marketing Automation](https://www.marketsizer.io/solutions/marketing-automation)
 - [Marketing Teams](https://www.marketsizer.io/solutions/marketing-teams)
 - [Revenue Operations](https://www.marketsizer.io/solutions/revenue-operations)
 - [RevOps Consultancies](https://www.marketsizer.io/solutions/revops-consultancies)
 - [SaaS Vendors](https://www.marketsizer.io/solutions/saas-vendors)
 - [Sales Enablement](https://www.marketsizer.io/solutions/sales-enablement)
 - [Sales Teams](https://www.marketsizer.io/solutions/sales-teams)

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  ## API Reference

  **Base URL**: `https://api.marketsizer.io`
  **OpenAPI Spec**: `https://api.marketsizer.io/openapi.json` (OpenAPI 3.0.0)
  **Interactive Docs**: `https://api.marketsizer.io/api-docs/`
  **Authentication**: Bearer token obtained via `POST /usertoken`
  **Alternative Auth**: `mskey` header or `x-api-key` header

  ### Enrichment Endpoints

  | Endpoint | Method | Description |
  |---|---|---|
  | `/enrich` | POST | Primary company enrichment - tech stack, subscriptions, Opportunity Score, competitive context. Supports pagination. |
  | `/subscription` | POST | Subscription-specific enrichment data |
  | `/company` | POST | Company enrichment with pagination |
  | `/company-history` | POST | Historical company data and trend analysis |
  | `/company-data/batch` | POST | Batch company data retrieval (multiple domains) |
  | `/vendor-offering` | POST | Vendor offering details |
  | `/vendor` | POST | Vendor data with pagination |
  | `/vendor-offerings/list` | POST | List vendor offerings with search |
  | `/vendor-offerings/{id}` | GET | Specific offering details |
  | `/subscription-arrs` | POST | Subscription ARR data |

  ### Discovery Endpoints

  | Endpoint | Method | Description |
  |---|---|---|
  | `/discovery` | POST | Primary discovery - filter by vendor stack, intent, ICP tier, country, traffic band, subscription state. Supports sorting
  and pagination. |
  | `/discovery/counts` | POST | Count matching records before pulling full data |
  | `/discovery/health` | GET | Discovery service health check |
  | `/discovery/warm-cache` | POST | Pre-warm discovery cache for faster queries |
  | `/discovery/warm` | POST | Trigger cache warming |
  | `/discovery/warm-status` | GET | Cache warming progress |

  ### Competitive Intelligence Endpoints

  | Endpoint | Method | Description |
  |---|---|---|
  | `/vendor-competitive-intel` | POST | Competitive intelligence analysis for a vendor |
  | `/vendor-competitive-recommendations` | POST | AI-powered competitive recommendations with type/limit filters |
  | `/vendor-competitor` | POST | Competitor vendor relationship data |

  ### Customer Intelligence Endpoints

  | Endpoint | Method | Description |
  |---|---|---|
  | `/customer-intel` | POST | Query customer intelligence data - health, signals, risk |
  | `/customer-intel/refresh` | POST | Refresh intelligence data |
  | `/customer-intel/refresh/status` | GET | Refresh operation status |
  | `/customer-intel/warm` | POST | Warm customer intel cache |
  | `/customer-intel/events` | GET | Customer events timeline |
  | `/customer-intel/health` | POST | Health metrics for customer accounts |
  | `/customer-intel/signal-summary` | GET | Summary of active intelligence signals |

  ### CRM Integration Endpoints

  **HubSpot** (Native OAuth):
  | Endpoint | Method | Description |
  |---|---|---|
  | `/hubspot/status` | GET | Connection status |
  | `/hubspot/check` | POST | Validate domain exists in HubSpot |
  | `/hubspot/push` | POST | Push enriched data to HubSpot |
  | `/hubspot/enrich` | POST | Enrich via HubSpot integration |
  | `/hubspot/workflow-enrich` | POST | HubSpot workflow-triggered enrichment |

  **Zoho CRM** (Native OAuth):
  | Endpoint | Method | Description |
  |---|---|---|
  | `/zoho/auth` | GET | Initiate Zoho OAuth flow |
  | `/zoho/callback` | GET | OAuth completion callback |
  | `/zoho/status` | GET | Connection status |
  | `/zoho/check` | POST | Validate domain in Zoho |
  | `/zoho/push` | POST | Push enriched data to Zoho |
  | `/zoho/enrich` | POST | Enrich via Zoho integration |

  **Salesforce** (Native OAuth):
  | Endpoint | Method | Description |
  |---|---|---|
  | `/salesforces-auth` | GET | Initiate Salesforce OAuth |
  | `/salesforces/callback` | GET | OAuth completion |
  | `/salesforces-enrich` | POST | Enrich via Salesforce |
  | `/salesforce/status` | GET | Connection status |

  **Freshworks**:
  | Endpoint | Method | Description |
  |---|---|---|
  | `/freshwork/callback` | GET | Freshworks callback |
  | `/freshsales/status` | GET | Connection status |

  **Cross-CRM**:
  | Endpoint | Method | Description |
  |---|---|---|
  | `/connections` | GET | List all active CRM connections |
  | `/auth/callback` | GET | Generic OAuth callback handler |

  ### Credit & Account Management

  | Endpoint | Method | Description |
  |---|---|---|
  | `/usertoken` | POST | Generate bearer token |
  | `/getPlanDetails` | POST | Retrieve plan and credit information |
  | `/store-usage` | POST | Log API usage |

  ### Campaign & Market Endpoints

  | Endpoint | Method | Description |
  |---|---|---|
  | `/smart-campaign-domains` | POST | Domain targeting for campaigns |
  | `/markets/summary` | GET | Market overview summary |
  | `/brand-dashboard` | POST | Brand dashboard data |

  ---

  ## Use Cases

  ### Signal-Based Selling
  **Problem**: Sales teams waste pipeline on accounts that match ICP firmographics but aren't actively buying.
  **Solution**: MarketSizer's Discovery engine filters by active subscription signals - trials, evaluations, competitive switches - so reps work
  accounts with real buying activity, not just demographic fit.
  **API**: `POST /discovery` with intent signal filters → `POST /enrich` for full account detail → `POST /hubspot/push` to update CRM.

  ### Competitive Displacement
  **Problem**: You know a competitor exists in an account but don't know if the account is happy, evaluating alternatives, or actively switching.
  **Solution**: MarketSizer detects actual subscription changes - when an account starts trialling your competitor's alternative, downgrades their
  competitor subscription, or adds your category vendor.
  **API**: `POST /vendor-competitive-intel` → `POST /vendor-competitive-recommendations` for actionable next steps.

  ### Churn Early Warning
  **Problem**: Customer success teams discover churn reactively - at renewal time or when usage drops.
  **Solution**: MarketSizer monitors your customers' subscription ecosystem - detects when they trial competitors, add complementary/replacement
  tools, or show subscription health degradation.
  **API**: `POST /customer-intel` → `GET /customer-intel/signal-summary` → `GET /customer-intel/events` for timeline.

  ### ABM Targeting
  **Problem**: ABM campaigns target accounts based on firmographic fit and anonymous web visit intent, leading to low conversion rates.
  **Solution**: MarketSizer layers real subscription intent (active trials, vendor evaluations) on top of ICP scoring for ABM lists with verified
  buying activity.
  **API**: `POST /discovery` with ICP + intent filters → `POST /discovery/counts` to size the audience → `POST /smart-campaign-domains` for
  activation.

  ---

  ## Integration Patterns

  ### Automation Platform Integration
  MarketSizer integrates with N8n, Zoho Flow, and Make via its REST API. Common patterns:
  1. **Signal-triggered workflow**: Poll `/customer-intel/signal-summary` → trigger Slack alert on new competitive signal
  2. **Enrichment on CRM update**: New HubSpot deal created → call `/enrich` → update deal properties
  3. **Scheduled discovery**: Daily `/discovery` query → push new high-intent accounts to sales sequence

  ### Chrome Extension
  The MarketSizer Chrome extension ("Copilot") provides inline enrichment on any webpage or LinkedIn profile. It connects to the same API backend
  and works independently of CRM integration.

  ---

  ## Data Freshness

  | Data Type | Refresh Cycle | Source |
  |---|---|---|
  | Subscription signals | Daily | BigQuery → Azure PostgreSQL |
  | Vendor catalogue | Daily | BigQuery → Azure PostgreSQL (307M rows) |
  | Opportunity Score | On-demand (cached) | Computed from subscription + ICP + win probability models |
  | CRM sync | On push (user-triggered) | Via OAuth connection |

  ---

  ## Company Information

 - **Company**: MarketSizer
 - **Location**: Dublin, Ireland
 - **Website**: https://www.marketsizer.io
 - **Contact**: hello@marketsizer.io
 - **App**: https://app.marketsizer.io
 - **API**: https://api.marketsizer.io