Flatkey records 49,134 monthly visits with -40.8% month-over-month growth and Paid, Contact for Pricing pricing. Grammarly records 58,867,412 monthly visits with -1.5% growth and Freemium pricing.
One API key for frontier models, 1,000+ AI tools, and one invoice
Cross-platform AI writing assistant delivering real-time grammar correction, tone alignment, authorship tracking, and team style guides.
| Dimension / Metric | | |
|---|---|---|
| Official Domain | flatkey.ai | grammarly.com |
| Pricing Model | Paid, Contact for Pricing | Freemium |
| Monthly Visits | 49.13K (49,134) | 58.87M (58,867,412) |
| MoM Traffic Delta | -33.92K (-40.8%) | -916.08K (-1.5%) |
| Primary Market & Share | 🇨🇳 China (69.9%) | 🇺🇸 United States (51.9%) |
| Direct Visits / mo | 30.53K | 25.4M |
| User Rating | 4.1 | 4.4 |
| Supported Platforms | Website | Website |
One API key for frontier models, 1,000+ AI tools, and one invoice
Point your existing SDK at Flatkey's router URL and select models by ID instead of managing a credential per provider.
Frontier chat models and 1,000+ pay-per-call tools share one auth layer, one balance, and one invoice.
Issue scoped keys per agent or environment, capped by spend and restricted to approved models and tools.
Requests route across five channel classes; when one degrades the router reroutes, backed by a 99.5% SLA document.
Cross-platform AI writing assistant delivering real-time grammar correction, tone alignment, authorship tracking, and team style guides.
Works natively inside Chrome, Safari, Firefox, Edge, Windows, Mac, Google Docs, MS Office, and mobile keyboards to flag grammar mistakes, rewrite tangled sentences, and shift tone toward confident, empathetic, or executive registers.
Deploys contextual AI agents that predict how a target audience will react to a draft, locate credible supporting citations, grade essays against rubric criteria, and generate drafts using up to 2,000 monthly prompts on Pro.
Scans text against billions of web pages and academic databases for accidental plagiarism, detects AI-generated passages, and logs transparent document provenance via Authorship reports in Google Docs and Word.
Enables teams on Pro and Enterprise plans to codify company terminology, ban deprecated jargon, enforce inclusive language, insert shared Snippets, and surface internal company definitions inline.
Enterprise developer platform and API for deploying GPT-6 Astra, Sol, Luna, and realtime multimodal agents.
Enterprise developer platform and API for deploying GPT-6 Astra, Sol, Luna, and realtime multimodal agents.
SpecialistOutstanding for context-aware translation and professional writing refinement, but not designed as a dedicated grammar checker.
SpecialistOutstanding for context-aware translation and professional writing refinement, but not designed as a dedicated grammar checker.
Excels at heavy paraphrasing and text rewriting, but offers less seamless inline real-time proofreading across all apps.
Excels at heavy paraphrasing and text rewriting, but offers less seamless inline real-time proofreading across all apps.
Free / Open-sourceOne API key for hundreds of AI models from every major provider
Free / Open-sourceOne API key for hundreds of AI models from every major provider
Provides strong multilingual grammar and style checking across apps, but offers fewer advanced generative AI features.
Provides strong multilingual grammar and style checking across apps, but offers fewer advanced generative AI features.
Delivers deeper manuscript analysis and structural reports, but has a steeper learning curve than Grammarly.
Delivers deeper manuscript analysis and structural reports, but has a steeper learning curve than Grammarly.
SpecialistAI academic writing assistant that edits, cites, and checks your manuscript right where you write
SpecialistAI academic writing assistant that edits, cites, and checks your manuscript right where you write
Free / Open-sourceOne OpenAI-compatible gateway for adaptive LLM routing, guardrails, and spend control
Free / Open-sourceOne OpenAI-compatible gateway for adaptive LLM routing, guardrails, and spend control
SpecialistHighlights readability and sentence complexity visually, but lacks automated grammar correction and browser-wide extension support.
SpecialistHighlights readability and sentence complexity visually, but lacks automated grammar correction and browser-wide extension support.
Free / Open-sourceOne OpenAI-compatible API key for 500+ AI models
Free / Open-sourceOne OpenAI-compatible API key for 500+ AI models
Free / Open-sourceOne open-source AI gateway for 100+ LLM providers
Great for sentence-level tone adjustments and rewriting, but less comprehensive for standalone grammar rules and style guides.
Great for sentence-level tone adjustments and rewriting, but less comprehensive for standalone grammar rules and style guides.
