Polar Typescript SDK

What it does

When your agent uses it

• Implementing Polar customers and external IDs
• Customer portal sessions
• Customer-state entitlement checks
• Webhook validation and processing

Example prompts

• “/polar-typescript-sdk”

Requirements

• A credential in POLAR_ACCESS_TOKEN

Workflow steps

5 steps, taken from the first numbered list in SKILL.md.

1. 1Identify the installed @polar-sh/sdk version and preserve the API version already selected by the application.
2. 2Inspect generated service signatures, model interfaces, response types, and endpoint-specific errors before writing calls.
3. 3Use createPolar for the full service client. Use createPolarCore with individual service functions when bundle size or tree-shaking matters.
4. 4Identify whether the access token is scoped to an organization. When the selected token does not imply one, create the client with…
5. 5Keep client, webhook, and environment configuration in trusted server-side code.

What it can do on your machine

Read from SKILL.md and the folder at commit e4fc909. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names these keys or tokens, usually read from environment variables:

  • POLAR_ACCESS_TOKEN

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Polar Typescript SDK loads about 2k tokens when it runs, and up to ~5.1k if it reads all its reference files. Until then it costs about 115 tokens; SKILL.md has 719 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~115

When it runs · the whole SKILL.md, loaded when a task matches

~2k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~5.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from polarsource/polar at commit e4fc909, republished under its Apache-2.0 licence (© polarsource). 719 words, ~1,989 tokens.

name

polar-typescript-sdk

description

Integrate Polar billing in server-side TypeScript applications using the versioned createPolar and createPolarCore clients. Use when implementing Polar customers and external IDs, checkout or customer portal sessions, customer-state entitlement checks, webhook validation and processing, API error handling, tree-shakable SDK calls, usage-event ingestion and metered billing, or migrating an application from the old Polar TypeScript SDK.

import { createPolar } from "@polar-sh/sdk/2026-10";

const accessToken = process.env.POLAR_ACCESS_TOKEN;
if (!accessToken) {
  throw new Error("POLAR_ACCESS_TOKEN is required");
}

const polar = createPolar({
  accessToken,
  environment: "sandbox",
});

const customerState = await polar.customers.getStateExternal("usr_123");

import { createPolarCore } from "@polar-sh/sdk/2026-10";
import { getStateExternalCustomers } from "@polar-sh/sdk/2026-10/services/customers";

const polarCore = createPolarCore({ accessToken });
const getCustomerState = getStateExternalCustomers(polarCore);
const customerState = await getCustomerState("usr_123");

for await (const customer of polar.customers.iterList({
  sorting: ["email"],
})) {
  console.log(customer.id);
}

const customer = await polar.customers.create({
  external_id: "usr_123",
  email: "user@example.com",
});
const customerState = await polar.customers.getStateExternal("usr_123");

const productId = process.env.POLAR_PRODUCT_ID;
if (!productId) {
  throw new Error("POLAR_PRODUCT_ID is required");
}

const checkout = await polar.checkouts.create({
  products: [productId],
  external_customer_id: "usr_123",
  success_url: "https://example.com/billing/success?checkout_id={CHECKOUT_ID}",
  return_url: "https://example.com/settings/billing",
});
redirect(checkout.url);

const session = await polar.customerSessions.create({
  external_customer_id: "usr_123",
  return_url: "https://example.com/settings/billing",
});
redirect(session.customer_portal_url);

const benefitId = process.env.POLAR_BENEFIT_ID;
if (!benefitId) {
  throw new Error("POLAR_BENEFIT_ID is required");
}

const customerState = await polar.customers.getStateExternal("usr_123");
const enabled = customerState.granted_benefits.some(
  (grant) => grant.benefit_id === benefitId,
);

await setFeatureAccess({
  customerExternalId: "usr_123",
  enabled,
});

© polarsource, Apache-2.0. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 4 other files (references) in sdk/typescript/.agents/skills/polar-typescript-sdk of polarsource/polar.

• SKILL.md
• agents/openai.yaml
• references/migration-from-v0.md
• references/usage-events.md
• references/webhooks.md

Open the folder on GitHubat commit e4fc909