BYOK AI Tools — Why You Shouldn't Pay Markup on API Calls

Most AI SaaS tools charge you $29/month for $3 worth of API calls

The 10× markup pays their margin. Hosting, customer support, onboarding emails, the CEO's salary. Normal business. Not evil.

But for you, the person actually using the tool, it's an opaque tax on infrastructure you could own directly.

CheckApp's markup is zero.

How the AI SaaS pricing model actually works

Here's what's happening behind almost every "AI-powered" subscription tool you're using.

The tool calls OpenAI, Anthropic, or some other provider on your behalf. That provider bills them fractions of a cent per token. They charge you a flat monthly fee — or worse, a per-document fee — that bundles in 3–10× the actual API cost.

That's not dishonest. It's just the business model. They built the wrapper, the UI, the integrations. Margin pays for those.

The problem is opacity. You don't know if you're paying $3 for API calls or $0.30. You don't know which model is running. You don't know whether they switched to a cheaper model last month and kept the price the same. You have no control over the spend and no visibility into the actual cost.

Grammarly Premium is $12/month for grammar, style, tone, and clarity across everything you write. Not a bad deal on its own. But if you scope it fairly against one slice of what CheckApp does — just the grammar skill — 20 articles/month is $0.60 per article for grammar and style. Comparing apples to apples.

CheckApp's grammar skill uses LanguageTool's free managed tier. Cost: $0.00.

BYOK: what it actually means

BYOK — Bring Your Own Key — means you configure your own API keys for the providers you choose. Your Exa key. Your Anthropic key. Your MiniMax key. Whatever you've signed up for.

When CheckApp runs a check, it calls those providers directly from your machine. The API calls go from your computer to Exa's servers, or Anthropic's servers, or LanguageTool's servers. CheckApp is not in the middle. There is no proxy. There is no re-billing.

You pay the provider's list price. Nothing more.

What a real check costs

Here's the actual math for an 800-word article, depending on which providers you configure.

Free-tier path — approach $0.00:

• Grammar: LanguageTool free managed tier — $0.00
• Academic citations: Semantic Scholar — $0.00 (no key required)
• Self-plagiarism: Upstash Vector (10k vectors free tier) — $0.00
• SEO: fully offline — $0.00
• Fact-check: disabled until you add an Exa key (see Standard path below)

Total for this configuration: $0.00.

Standard path — ~$0.05–$0.10:

• Fact-check: Exa Search — ~$0.03 (4 claims × $0.007/search)
• Grammar: LanguageTool free — $0.00
• LLM skills (tone, legal, summary): MiniMax — ~$0.01
• SEO: offline — $0.00

Total: ~$0.04–$0.08.

Premium path — up to $0.25:

• Fact-check: Exa Deep Reasoning — ~$0.025 (deeper sources, slower)
• Plagiarism: Copyscape — ~$0.09 (first 200 words + $0.01 per 100 after)
• AI Detection: Copyscape/Originality — ~$0.03
• LLM skills: Anthropic Claude — ~$0.05 (more expensive model)

Total: ~$0.20–$0.25.

You pick the configuration. You see the estimate before running:

checkapp --estimate-cost article.md

The dashboard's Run Check page also shows the estimate before you spend anything.

The privacy argument nobody says out loud

When a SaaS tool calls AI on your behalf, your text goes through their servers.

You're trusting them, their data retention policies, their security practices, and whatever subprocessors they've added to their privacy policy. That's one extra layer of trust for every provider in the chain.

With BYOK, your text goes to the provider you chose. If you trust Anthropic's data policy, CheckApp doesn't add a second layer. If you configure a self-hosted LanguageTool instance, your text never leaves your machine at all.

Your text. Your provider. Your policy. CheckApp never sees it, never stores it, never proxies it.

The honest trade-off

BYOK isn't frictionless. I'll say that plainly.

You manage 3–5 API keys instead of one subscription. You handle provider-specific rate limits yourself. You pay for test runs, failed configurations, and the occasional edge case that consumes more tokens than expected. If a provider changes their pricing, you absorb that change directly.

For users who want zero setup, BYOK is more overhead than a managed subscription. We're honest about that. We may offer an optional managed-keys tier at public launch for users who prefer one billing line — priced at actual cost plus a small, transparent margin. If we do, the BYOK path stays free forever.

But for developers, content teams, and anyone running volume — BYOK is cheaper, more transparent, and more private than any subscription wrapper.

Install it. No signup required.

npm install -g checkapp
checkapp --setup
checkapp article.md

--setup walks you through provider configuration. Start with LanguageTool (free) for grammar and Semantic Scholar (free, no key) for academic citations. Add Exa Search for fact-check when you're ready to pay a few cents per article. Run your first check for free; add paid providers as you need them.

The dashboard (checkapp --ui, opens at localhost:3000) shows provider settings, per-skill configuration, and cost estimates before every run.

For Claude Code users: install the MCP server from the GitHub repo. check_article becomes a native tool. Your agent drafts. Then it checks.

No account. No waitlist. No margin.