FAQ

What is RLB Whisk?

A deterministic multilingual spellcheck API. 49 languages, real Hunspell engine, frequency + bigram context ranking. Same input, same output every time. Free to use.

How is this different from Grammarly / LanguageTool / Microsoft Editor?

• Privacy: Whisk has an Airplane mode that runs 100% locally in your browser. Nothing else offers that as a demonstrable technical proof.
• Determinism: same input → same output, always. LLM-based tools can't promise this.
• Multilingual: 49 languages treated equally. Others are English-first.
• Free open API: no freemium tiers up front.
• Scope: we ship spelling well before we ship grammar. Grammarly and LanguageTool have more grammar rules; we have more privacy and more languages.

Is it really free?

Yes. Free tier: 100 requests/hour per IP anonymous, 10,000/hour per API key. A paid Studio tier (100,000/hour) is planned for future heavy usage but the free tier is not a trial — it stays free.

Do you log my text?

No. Server logs record endpoint / timestamp / latency / status code / response size / error class. We never log request or response bodies. See Privacy for the full contract. If you don't want to trust us, use Airplane mode.

What is Airplane mode?

A one-click toggle in the Whisk web app. When on, the full Hunspell + spylls stack runs locally in your browser via Pyodide + WASM. Zero network calls. Verify with your browser's Network tab or by turning wifi off after the "Save for offline" click.

Which languages are supported?

49 currently: af, ar, be, bg, bn, br, bs, ca, cs, da, de, el, en, es, et, eu, fr, gd, gl, gu, he, hi, hr, hu, id, is, it, kk, ko, lt, lv, ml, ne, nl, no, pl, pt, ro, ru, si, sk, sl, sr, sv, sw, te, tr, uk, vi. See live: /api/v1/spellcheck/languages.

Airplane mode currently covers en, es, de, fr, it, pt, nl, ru. More arrive as browser-mode dictionaries are added.

What about Hinglish, Singlish, GenZ / SMS lingo?

Planned. These are variants none of the incumbent spellcheckers handle — they flag every word as an error. Once shipped they'll be accepted and auto-corrected within their own vocabulary (typos in Hinglish get fixed to correct Hinglish, etc.).

What about grammar?

Not yet. Whisk is spelling-first. Grammar and style are planned for later tools in the Whisk family.

Can I self-host?

Server code is closed source. The SDKs (rlbwhisk, @rlbwhisk/client, rlbwhisk-mcp) are open MIT — you can inspect and audit those. If you need self-hosting for compliance, contact us; a licensed Studio option is on the roadmap.

Alternative for full independence today: use Airplane mode in the Whisk web app. That runs entirely on your machine.

How reliable is it?

Live status at /whisk/status/. Health endpoint at /api/v1/health. Rate-limit and version headers on every response. No SLA is offered on the free tier — production users on Studio (when it ships) will get a 99.9% target.

What if the API is down?

Airplane mode keeps working in the browser without any server. For API clients, the SDKs auto-retry on transient errors. Longer outages: check status.

Where's the source code?

Server-side stays closed; that's the IP. Client-side SDKs are open MIT (Python, JavaScript, MCP).

How do I install for Word / VS Code / mobile keyboard?

Coming. In order: Chrome extension → Firefox extension → Microsoft Word add-in → Android keyboard → iOS keyboard. See the launch roadmap in the strategy memory.

How do I report a bug or ask a question?

Include the X-Request-ID from a failed response. Contact: [email protected] (or the appropriate SDK repo issue tracker).

Do you support IPv6 / TLS 1.3 / HTTP/3 / …?

Cloudflare fronts every request, so yes to all standard modern transport features.