BYOK AI Writer: Your Own AI API Key, Paid Once for Life

”BYOK” means bring your own key. With a BYOK AI writer, the AI cost moves off the tool’s price list and onto a meter you control.

What a BYOK AI writer is, and why it changes the cost

Every AI writing tool pays an AI company behind the scenes. On a normal plan, the tool buys tokens, adds its margin and risk, and sells you “words” or “credits”. You never see the real AI cost.

A BYOK tool splits that bill in two:

• The AI company charges you directly for the tokens your articles use, at its own published price.
• The writing tool charges you for everything else: structure, research steps, SEO checks, publishing.

That split changes three things.

You pay the AI’s real price. Capable models are now cheap, and with your own key that saving reaches you.

You choose the model. A premium model for a money roundup, a budget one for a short how-to.

The tool can sell a fixed price. It no longer carries your AI bill, so it can sell a one-time lifetime plan without betting on how much you write. That is why Affpilot offers BYOK as a lifetime plan.

BYOK does not make AI free. It makes the AI cost yours to see, choose and cap.

What to check in any BYOK AI writer

Before you trust any tool with a key, ask five questions:

• Where does my key go? It should go only to the AI company’s official address.
• How is it stored? Look for encryption, and a page that never shows the full key again.
• Can I add more than one key, and in what order are they tried?
• If every key fails, does the tool stop, or does it quietly switch to its own AI and charge me?
• Is there a monthly word limit? Many tools have one, even when the AI bill is yours.

The rest of this guide answers each question for Affpilot.

What one article really costs: a worked example

AI companies charge per token, a piece of a word. Anthropic’s pricing page estimates one token at about 0.75 English words. But an article tool makes many calls per article: outline, sections, repairs, meta description. Each call sends instructions (input tokens) and gets text back (output tokens).

So we measured. On 28 September 2026 we wrote 10 test articles through a BYOK account in Affpilot: 5 Magic Writer articles, 2 Amazon Top-10s, 2 single product reviews and 1 comparison. Together they made 88 AI calls, used 222,460 input tokens and 47,763 output tokens, and produced 20,808 words.

The arithmetic

• Input per 1,000 words written: 222,460 ÷ 20.808 ≈ 10,700 tokens.
• Output per 1,000 words written: 47,763 ÷ 20.808 ≈ 2,300 tokens.
• For a 1,500-word article, rounded up: about 16,000 input and 3,500 output tokens.

Cost = (input tokens × input price + output tokens × output price) ÷ 1,000,000. For Gemini 3.8 Flash at $0.75 input and $3.75 output per million tokens: (16,000 × 0.75 + 3,500 × 3.75) ÷ 1,000,000 = $0.012 + $0.013 = about $0.025 per article.

Prices checked on 4 October 2026: OpenAI API pricing, Gemini API pricing, Claude API pricing, DeepSeek pricing and xKiro usage and limits. Anthropic says its newer models count about 30% more tokens for the same text, so we added 30% to the two Claude rows. Google’s Gemini 3.8 Flash price is a promotion: from 1 January 2027 it doubles, so that row becomes about $0.05 per article.

About the free row: xKiro gives 500,000 free-model tokens a day, or 1,000,000 after you verify on Telegram (xKiro’s pricing, checked 4 October 2026). At about 19,500 tokens per article, that is roughly 25 articles a day. The allowance belongs to your xKiro account, so two keys from one account share it.

Which AI companies you can use in Affpilot

In Affpilot you can add keys from 11 AI companies. Each key goes only to that company’s official address. Azure is the exception: you enter your own address, and Affpilot accepts only Microsoft’s Azure OpenAI domains.

How to get an AI API key safely

An AI API key is a password that also carries your credit card: anyone who has it can spend your money.

Google Gemini

Sign in to Google AI Studio, open Get API key and create a key. Older Gemini keys start with “AIza”. Since 28 May 2026, Google creates new keys in a newer format, so a different start is normal. To go beyond the free tier, use Set up billing, then set a monthly spend cap on the Spend page. Google calls the cap experimental: spend can run over for about 10 minutes. The steps are in Google’s Gemini API billing guide.

xKiro

Create a free account, open the API Keys page in the dashboard, and create a key. No card is needed for the free models. xKiro also offers per-key spending limits.

OpenAI

Sign in at the OpenAI platform, open API keys and create a new secret key (it starts with “sk-“). Add billing credit. Then open Project settings → Limits and turn on “Enforce a hard limit”, as the OpenAI spend limits guide describes. Without that switch, you only get an alert and the spending goes on. Even with it, OpenAI says spend can go slightly over the limit.

Anthropic (Claude)

In the Claude Console, open API keys and create one (it starts with “sk-ant-“). Then open Settings → Billing and, under Spend limits, set your own monthly limit.

OpenRouter, DeepSeek, Mistral, xAI, Groq, Alibaba

Each has an “API keys” page in its console. When you pick a company in Affpilot’s key form, the form links to that page and shows what the key should look like.

• Create a new key just for Affpilot. Never reuse the one your other apps use.
• Set a hard spend limit at the AI company before you write your first article.
• Paste the key only into the key form. Never send it in a chat, an email, a support ticket or a screenshot, not even to us.
• If a key may have leaked, delete it at the AI company first, then add a new one in Affpilot.

Set up your AI API key in Affpilot

Once you have a key, setup takes a few minutes. You can save keys at any time, but writing with them needs a plan, so start there.

1. Pick a lifetime BYOK plan

   On the pricing page, choose Lifetime 1.5M, 3M or 10M. Pay in taka with bKash, Nagad, Rocket or a local card, or in dollars with an international card.

2. Open “Your own AI API keys”

   In the left menu, open Settings, then the Your own AI API keys card. The top of the page shows your plan, the words used this month and the date new words arrive.

3. Add your first key

   In Add a key, choose the company under Which AI company?, paste the key, and type the model name exactly as the company writes it. The form shows an example model for each company.

4. Press “Save and test”

   Affpilot saves the key locked (encrypted) and makes one tiny test call right away. The row then says Working, or Not working with the company’s own reason.

5. Tick “Write with my own API keys”

   On a write page (Magic Writer, the Amazon writers, YouTube to article and others), tick Write with my own API keys. The words then come from your BYOK plan, not your normal word balance.

Articles publish to WordPress and Blogspot as on any other plan. Not connected yet? See how to add a WordPress site to Affpilot or connect a Blogger site. Writing many titles at once (one per line) works with your own keys too; see AI bulk article generation.

”Add best models”: the strongest models in one click

The hard part of BYOK is not the key. It is knowing which of dozens of models write long articles well, which are cheap, and which are about to retire. Affpilot keeps a ranked list per company of text models that can write long articles, checked against each company’s own model pages.

1. Get one key working first

   The card appears only after a key passes its test.

2. Press “Add best models”

   A card under Your keys says “Add the best models for this key — one click”. For xKiro it says “best free models”.

3. Choose 5, 10 or 15

   10 is marked Recommended. The dialog lists exactly what will be added, in order, with “Free” badges where they apply.

4. Confirm

   Affpilot adds each model as a row that uses the same key, puts them in the best order, and tests model number 1.

Where the company allows it, we first ask which models your key can use, and add only those. Each model is one row and counts toward your limit of 10 keys, so “15” only fills the free slots you have. Models you switched off stay off.

Fallback: how several keys keep an article alive

A single key is a single point of failure: credit runs out, a model retires, the company has a bad hour. Affpilot tries your keys in order and reacts to the kind of failure:

How you order the chain is a real decision:

• Cheapest first, premium last. Free xKiro models first, a paid key at the end. You pay only when the free path fails.
• Different companies, not just different keys. Two keys from one xKiro account share one daily allowance, so they fail together.
• Best quality first, for money articles where a weaker model costs you rankings.

Reorder with the ▲ ▼ buttons or by dragging a key by its dots. Switch a key off without deleting it.

Lifetime or monthly: a decision table

Affpilot sells three ways to write. All prices below are as shown on the live pricing page and lifetime deal page on 4 October 2026.

Two worked scenarios

A blogger writing 60 articles of 1,500 words a month (90,000 words). Our-AI Lite costs $19 a month, or $228 over twelve months. The Bronze lifetime deal costs $129 once and covers 100,000 words a month with no AI bill. Lifetime 1.5M costs $164 once, plus about $1.51 a month on Gemini 3.8 Flash ($18 a year) or $0 on free xKiro models. At this volume, Bronze is the simpler and cheaper choice. BYOK only wins if you want to pick the model yourself.

A small agency writing 400 articles of 1,500 words a month (600,000 words). Monthly needs Pro at $99 a month (1,000,000 words), which is $1,188 over a year. Platinum’s 500,000 words are too few. Lifetime 1.5M costs $164 once, plus about $10 a month on Gemini 3.8 Flash ($120 a year) or about $27 a month on GPT-6.1 Sol. The first year then costs about $284 or $486, and later years cost only the AI bill. Even if Google’s Flash price doubles in January 2027 as announced, that bill is about $20 a month. At this volume, BYOK is clearly cheaper, and 400 articles still leaves 900,000 words a month unused.

Lifetime means one payment, then new words every month on the day you bought, for as long as Affpilot runs. Unused words do not carry over. A bigger BYOK plan later costs only the difference.

Risks and limits to know before you pay

The AI company’s limits are now your limits

Every company caps how fast you can call it, and our test made about 9 AI calls per article. On OpenRouter’s free models, the limit is 50 requests a day until you have bought $10 of credit, which is only about five articles. That is why “Add best models” never picks OpenRouter’s free models. A key from a second company is your best protection.

Models change and retire

Companies rename, reprice and retire models on their own schedule. When a model disappears, the chain moves on. Press “Add best models” every few weeks to refresh your list.

Quality and speed differ by model

Free and cheap models can write well, but not equally well or fast. In our 10-article test, xKiro’s free Qwen3.8 Max took 2 to 4 minutes per article, about three to four times slower than our own default service. One of the ten gave a measurement the wrong way round, which would have damaged a reader’s work. Read every article before you publish, whatever the model.

What the plan does not cover

BYOK covers text. AI pictures and videos use your image and video credits. An Amazon article uses a few extra words from your plan for the product search. Every BYOK plan has a monthly word limit, because our servers and the product search still cost us to run.

How Affpilot stores your AI API key

Here is what our code does with your key.

• Encrypted at rest. Each key is stored as a Fernet token (AES-128 encryption with an HMAC-SHA256 check). The secret that decrypts it is not kept in the database, so a copy of the database or a backup alone does not reveal your keys.
• Never shown again. After you save a key, the page shows only its last four characters. The edit form’s key box always stays empty.
• Owner only. Keys belong to the workspace owner. Team members can write with them but can never see or change them.
• Official addresses only. The address is checked again each time an article is written, not only when you save the key.
• Kept out of logs. Error messages are cleaned so a key echoed back by a company is masked, and crash reports never carry the key you pasted.

One honest limit: to call the AI company, our server must decrypt the key while it writes. Encryption protects the stored copy, not a key on a fully compromised server. That is why a separate key with a hard spend limit is the right habit with any tool.

Who BYOK suits, and who should skip it

Still deciding whether AI writing fits your site? Read whether you should use AI to write blog posts. Refunds follow our refund policy.

Frequently asked questions

Is a BYOK AI writer really free to use?

No. You pay the writing tool for the software and the AI company for tokens. The AI part can cost nothing on a free tier, such as xKiro’s free models or Gemini’s free tier, within their daily limits. On paid models, a 1,500-word article costs from under one cent to about 17 cents, depending on the model.

Which AI API key is best for writing articles?

No single key is best; choose by budget and volume. An xKiro key with its free Qwen models is the easiest free start. Gemini Flash gives low cost and steady quality. Claude and the top OpenAI models write strong prose but cost more. Add keys from several companies, cheapest first, so one failure never stops an article.

Can I use a free AI API key with Affpilot?

Yes. xKiro’s free models and Google Gemini’s free tier both work, and “Add best models” picks only free models for an xKiro key. Free tiers have daily limits: xKiro’s basic free plan gives 500,000 tokens a day per account, enough for roughly 25 articles. Google may use free-tier content to improve its products.

What happens if my AI API key runs out of credit mid-article?

Affpilot skips that key and tries your next key at once. If every key fails, the article stops and the words it reserved go back to your plan. Affpilot never finishes the article with its own AI behind your back. The key’s row shows the AI company’s reason, so you know what to fix.

Is it safe to give my AI API key to a writing tool?

It is safe when the tool encrypts keys and you limit what each key can spend. Affpilot stores keys encrypted, shows only the last four characters and sends them only to the AI company’s official address. On your side, create a separate key for each tool, set a hard spend limit, and never paste a key into a chat or email.

Does a lifetime BYOK plan give unlimited words?

No. Each Affpilot plan has a fixed monthly allowance: 1,500,000, 3,000,000 or 10,000,000 words. New words arrive every month on the day you bought, and unused words do not carry over. That is about 1,000, 2,000 or 6,666 articles of 1,500 words a month, which is more than most sites publish.

Can I use both Affpilot’s AI and my own AI API key?

Yes, they are separate. On each write page, tick “Write with my own API keys” to use your BYOK plan, or leave it unticked to spend your normal word balance on Affpilot’s AI. If you already hold a lifetime deal on Affpilot’s AI, you keep it alongside a BYOK plan.

Do I need a credit card to get an AI API key?

Not always. xKiro’s free plan needs no card, and Google AI Studio gives a free-tier Gemini key before you set up billing. OpenAI, Anthropic and DeepSeek charge per token, so you add a payment method or credit before real use. Whichever you choose, set a spend limit on the day you add the card.