# Polar

Merchant-of-record billing and checkout for digital products, with an official hosted MCP and SDKs.

Hosted platform for selling digital products, subscriptions, usage-based billing, and license keys, acting as merchant of record for tax. The Builder publishes a REST API, JS and Python SDKs, and an MCP server at mcp.polar.sh (production and sandbox). Source is Apache-2.0 on GitHub but the Builder does not document self-hosting.

Alternative to: Gumroad, Lemon Squeezy, Paddle

- Capabilities: operable
- Vertical: ecommerce
- Shape: product
- Form factor: api
- Execution model: deterministic
- Provenance: human-written (recorded, never ranked)
- Repo: https://github.com/polarsource/polar (Apache-2.0), 10229 stars, last commit 2026-09-02
- Last activity: 2026-09-02
- Page: apps/polarsource--polar.html
- JSON: apps/polarsource--polar.json

## Use it when

- I sell software, courses, or API credits and want someone else to handle VAT and sales tax
- my agent should create products, checkout links, and discounts and read orders through an official API or MCP

## Gotchas

- Fees are per transaction: Starter 5% + 50c, Pro 3.8% + 40c, Growth 3.6% + 35c, Scale 3.4% + 30c; no flat monthly price
- MCP docs give endpoints and client setup but no tool list; treat MCP coverage as the API's until verified
- Self-hosting is not documented; the repo is for contribution

## Editions

- Starter: Free, closed source
  - hosted: https://polar.sh
- Pro: Free, closed source
  - hosted: https://polar.sh/docs/documentation/polar-as-merchant-of-record/fees
- Growth: Free, closed source
- Scale: Free, closed source

## Operable: what an agent can drive

Operability: official. Interface: api at https://polar.sh/docs/api-reference (published by the builder, remote).

### Reach (partial coverage)

- Create and manage products and prices: reachable. API reference: Products
- Create checkout sessions and links: reachable. API reference: Checkouts
- List and manage orders and refunds: reachable. API reference: Orders, Refunds
- Manage subscriptions: reachable. API reference: Subscriptions
- Manage customers: reachable. API reference: Customers
- Benefits and license keys: reachable. API reference: Benefits, License Keys
- Discounts: reachable. API reference: Discounts
- Usage meters and events: reachable. API reference: Meters
- Webhooks: reachable. API reference: Webhooks
- Payout and tax filing: not reachable. handled by Polar as merchant of record; dashboard only

## Code stack

- Languages: Python, TypeScript
- Frameworks: FastAPI, Next.js
- Package manager: none
- Database: PostgreSQL
- Hosting target: polar.sh

## Skills

contributor: Repo tooling for Polar contributors: billing review, API surface review, local environment, ADR checks.
- Paths: .agents/skills/*/SKILL.md

## Evidence and confidence

- formFactor: hosted service with REST API, SDKs, and MCP (confidence 0.9)
- executionModel: no model at runtime (confidence 0.95)
- operability: polar.sh/docs/integrate/mcp lists mcp.polar.sh endpoints; API reference and SDKs under polarsource (confidence 0.9)
- effort: no supported self-host; customization null (confidence 0)
- editions: README Pricing section lists Starter free plus fees and paid tiers (confidence 0.85)
- active: pushedAt 2026-09-02
- reach:  (confidence 0.8)

## Open questions

- Tool names exposed by mcp.polar.sh and its auth flow
- Whether self-hosting is supported at all (DEVELOPMENT.md is for contributors)

## Sources

- https://github.com/polarsource/polar (sourcing:ecommerce:vendor)
- https://polar.sh/docs/integrate/mcp (sourcing:ecommerce:vendor)
- https://polar.sh/docs/llms.txt (analysis)