ChatGPT Tax ID & Invoices: OpenAI API Key and First Call

If OpenAI charges Taiwan VAT on a given transaction, its official notice says the eGUI will be sent to the account email. Entering a valid Taiwan VAT ID affects tax handling, but it does not mean every transaction will produce an eGUI. OpenAI Taiwan VAT/eGUI notice checked: 2026-09-24. OpenAI Taiwan VAT/eGUI official notice.

Applying for an OpenAI API Key and Making Your First ChatGPT API Call

The OpenAI API is a developer interface billed by model and token usage; ChatGPT subscriptions and API billing are kept separate. You create an API key in the project settings on OpenAI Platform, and once it is created you can send your first request with the Responses API. This article gets you connected first, then covers the Taiwan billing and invoice notes below.

Applying for an OpenAI API Key: Three Steps in Project Settings

1. Sign in to OpenAI Platform and select your organization and the project you want to use.
2. Open Settings → Project → API Keys, click "Create new secret key", name the key, and choose All, Restricted, or Read Only permissions depending on what the work requires. A project key can only be used within its own project.
3. Put the key into an environment variable in your terminal. Do not paste it into frontend code, a public repository, or a chat log.

OpenAI official project key management and quickstart documentation checked: 2026-09-24: Project API Keys, API quickstart.

First Request: OpenAI's Official Responses API

The example below uses the environment variable OPENAI_API_KEY and calls the official endpoint https://api.openai.com/v1/responses. The GPT-6 Sol Responses API and model support were checked against the official documentation on 2026-09-24.

export OPENAI_API_KEY="your-project-key"
curl https://api.openai.com/v1/responses \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-6-sol","input":"Explain in one sentence what an API key is."}'

Using an OpenAI-Compatible API

If your code uses the OpenAI Chat Completions format, you can point it at the BazaarLink API base URL. First create a key in your BazaarLink account and put it in BAZAARLINK_API_KEY; check the public models list for model IDs.

export BAZAARLINK_API_KEY="your-bazaarlink-key"
curl https://api.bazaarlink.ai/v1/chat/completions \
  -H "Authorization: Bearer $BAZAARLINK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-6-sol","messages":[{"role":"user","content":"Explain in one sentence what an API key is."}]}'

How OpenAI API Pricing Works

Prices are quoted per million tokens (MTok). The GPT-6 Sol standard prices checked on 2026-09-24 are US$2 for input and US$10 for output; cache reads are US$0.20 and cache writes are US$2.50. When a request exceeds the long-context threshold listed in the official documentation, a separate pricing rule applies to that request. BazaarLink's current catalog also lists GPT-6 Sol at US$2 / US$10. You can verify it on the GPT-6 Sol model page, find every callable ID in the public models list, and check cache and promotion fields in the public pricing catalog. Price check date: 2026-09-24. For comparisons across other models, see 2026 AI API Pricing Comparison.

Once you have a key, first confirm the API user, project, and usage records, then review the Taiwan VAT/eGUI, receipt, and company billing entry points below. Entering billing fields and receiving a particular transaction document are different questions, so check against the actual transaction page. You can also read the Claude API Taiwan Purchasing Guide and the Gemini API Application Guide.

OpenAI has an official eGUI notice for Taiwan, but it applies only when Taiwan VAT is charged on the transaction. Entering a Tax ID does not guarantee you will receive a VAT-inclusive electronic uniform invoice. Companies should first enter correct billing details, then confirm the actual buyer, purchase channel, tax amount, and documents before processing expense reports.

This article reflects official documentation checked on 2026-09-17. ChatGPT personal subscriptions, Business workspaces, the OpenAI API, and App Store transactions each have different billing entry points, so a single set of steps does not cover all of them.

Taiwan VAT and eGUI: First Check Whether the Transaction Was Taxed

According to the OpenAI Taiwan VAT and eGUI official notice, Taiwan customers who do not provide a Taiwan VAT ID are subject to OpenAI's 5% VAT arrangement. When VAT is charged, the eGUI is sent from noreply@tax.openai.com to the email associated with the account, and it can also be looked up on the Ministry of Finance e-invoice platform as described in the official notice.

A valid Taiwan VAT ID affects tax handling. You cannot treat it as both "entering a Tax ID means B2B" and "you will definitely get a deductible VAT-inclusive eGUI." What a company needs to confirm is the actual document and the buyer's identity, not merely whether a Tax ID field has been filled in. An invoice PDF from billing should also not be treated as an eGUI automatically.

How to Enter Your OpenAI Tax ID: By Account Type

The first three rows follow the OpenAI billing and Tax/VAT ID update notice. Fill in the company title, Tax ID, and billing address for the actual buyer. An invalid Tax ID may be removed and the applicable tax charged, so do not enter another buyer's details just to obtain a different document.

Updates only affect future invoices; documents already issued cannot be retroactively changed in settings. If you discover an error after paying, keep the invoice number and request a review or possible reissue from OpenAI support. Do not promise that the Tax ID can definitely be fixed, and do not pay again yourself to "get one more."

Where to Find Invoices, Receipts, and API Prepaid Billing

First check the seller and channel on the payment email, then locate the document. For ChatGPT on the website, use its billing entry point; for Business, the workspace owner checks billing; for store transactions, go to your Apple or Google purchase record. An eGUI, if the conditions for issuance are met, is a separately sent tax document; downloading a billing PDF alone does not mean you have found it.

For the API, check Billing history on the API platform. According to the OpenAI API invoice notice, Enterprise API accounts receive monthly invoices per contract; other accounts receive prepayment, payment, or usage documents according to their billing method. Do not treat all API accounts as the same monthly billing cycle, and do not equate a prepayment amount directly with the cost used in the current month.

If you cannot find the data, check the sign-in account, API organization, Business workspace, and billing email. An employee having a ChatGPT login does not mean they have billing permissions for an API organization or workspace.

Expense Reporting and Input Tax Credit Are Not the Same Button

Payment proof, invoices, eGUIs, and usage records each serve a different purpose. Expense recognition depends on the actual transaction and business purpose. Input tax deduction for VAT depends on other conditions such as the buyer, tax amount, documents, and purpose, so you cannot write "having an eGUI means it is all deductible."

Business buyers in Taiwan and individual buyers are treated differently for cross-border electronic services. The Ministry of Finance notice and Article 36 of the Business Tax Act set out arrangements for buyers and taxable use. Have your accountant confirm first, rather than assuming you must always pay 5% again or that cross-border services never need handling.

Paying out of pocket with a personal card does not automatically rule out reimbursement. The company should confirm the actual buyer, purpose, payment, reconciliation, and authorization records. If internal controls require triplicate invoices, confirm what the channel can provide before ordering. For a list of relevant documents, see the AI API Expense Reporting Process.

Buy Directly From the Official Provider, or Through a Taiwan API Service?

If you need the official ChatGPT chat interface, a subscription login, or specific product tools, prefer the official plan that fits your needs. Buying model API access does not guarantee those product features are fully replicated. If you only need a single model and can handle billing and integration yourself, the official API is also a valid option to compare.

Reasons to compare a Taiwan API service include consolidating multi-model usage, NT-dollar pricing, local documentation, and payment or enterprise procurement workflows. Listing your required conditions and comparing features and total cost is more practical than deciding by counting how many requirements you have.

BazaarLink is provided by Jilian Technology Co., Ltd. (Tax ID 62232477), which can issue duplicate and triplicate electronic uniform invoices to buyers who meet the Taiwan transaction conditions. Confirm the title, Tax ID, purchase channel, and invoice details before paying; monthly billing can be arranged in advance. Company and enterprise partnership information lists contact details.

Model usage is checked against the customer prices and fee items in the current model catalog. Add-on and payment fees and NT-dollar conversion are on the payment page. This invoice corresponds to Jilian's API service and is not issued on behalf of the official ChatGPT subscription. The multi-model gateway also does not guarantee that all tool logins and official workflows are identical, so check the API documentation before integrating.

Research Grants and Public-Sector Procurement: Don't Just Check Whether Payment Was Made Before the Deadline

First confirm the documents the grant accepts, the reimbursement deadline, the service delivery and usage period, prepaid credit, and renewal rules. A subscription is not always unworkable, and a prepayment does not always mean the full amount can be claimed just because it was paid. Confirming these terms with accounting and the grant administrator before purchase is more effective than supplying documents after the fact.

For estimating monthly fees and API usage, see also ChatGPT Fees and Codex Fees.

TWD billing · Taiwan invoices · leading AI models · OpenAI-compatible API