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AI · head to head

AI21 Labs vs Grammarly

AI21 Labs logo

AI21 Labs

AI

Enterprise language AI solutions

From
Free
Rated
-
Full reviewWebsite
Grammarly logo

Grammarly

Documentation

Great writing, simplified

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: AI21 Labs the free allowance is $10 of credit lasting 7 days rather than an ongoing free tier; Grammarly occasional false positives and grammatically incorrect suggestions that can introduce errors
  • They diverge on capability: AI21 Labs covers Jamba models, Grammarly covers Grammar checking.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which AI21 Labs and Grammarly actually diverge.

Attributes where AI21 Labs and Grammarly differ
AttributeAI21 LabsGrammarly
Pricing modelusage-basedUnknown
PlatformsApi, CloudWeb, macOS, Windows, iOS, Android
CategoryAIDocumentation
Founded20172009

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in AI21 Labs

  • Jamba models
  • Long context
  • RAG engine
  • Writing tools
  • REST API
  • Amazon Bedrock
  • Cloud platforms
  • Api support

Only in Grammarly

  • Grammar checking
  • Spelling correction
  • Punctuation
  • Clarity suggestions
  • Engagement feedback
  • Delivery insights
  • Plagiarism checker
  • Citation generator

What people use each for

The jobs each tool is most often brought in to do.

AI21 Labs

  • Running long-context tasks on the Jamba model familynot Grammarly
  • Building and optimising production AI agents with Maestronot Grammarly
  • Routing between models to control cost and accuracynot Grammarly
  • Long-horizon agentic tasks needing stateful workspacesnot Grammarly

Grammarly

  • Email writingnot AI21 Labs
  • Document editingnot AI21 Labs
  • Academic writingnot AI21 Labs
  • Business communicationnot AI21 Labs
  • Content creationnot AI21 Labs

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

AI21 Labs

  • The free allowance is $10 of credit lasting 7 days rather than an ongoing free tier
  • Jamba Large is $2 per million input tokens and $8 per million output, so output-heavy work costs four times as much as input
  • Volume discounts, private cloud hosting and higher rate limits require a custom plan
  • Standard rate limits are not published

Grammarly

  • Occasional false positives and grammatically incorrect suggestions that can introduce errors
  • Privacy concerns about sending text to Grammarly's servers for analysis
  • AI capabilities sometimes produce hallucinations and fabricated citations that appear grammatically correct

Pricing, plan by plan

AI21 Labs

Free
  • Free TrialFree
    • 10 USD credits
    • 7-day trial period
    • No credit card required
  • Pay As You Go$undefined/mo
    • Usage-based pricing model
    • Access to all Foundation model APIs and SDK
    • Unlimited seats
  • Custom Plan$undefined/mo
    • Volume discounts on token pricing
    • Premium API rate limits
    • Private cloud hosting option

Grammarly

Free
  • FreeFree
    • Basic grammar and spelling checks
    • Tone visibility
    • 100 AI prompts per month
  • Pro$12/month
    • Sentence rewrites
    • Tone adjustment
    • Plagiarism and AI detection

Which should you pick?

Choose AI21 Labs if

  • You need jamba models.
  • You want to start without paying.
  • You work on Api, Cloud.
  • You also want long context.
AI21 Labs review

Choose Grammarly if

  • You need grammar checking.
  • You want to start without paying.
  • You work on Web, macOS, Windows, iOS, Android.
  • You also want spelling correction.
Grammarly review

Questions people ask

Is AI21 Labs or Grammarly better?
Neither clearly leads. AI21 Labs starts at Free and Grammarly at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, AI21 Labs or Grammarly?
AI21 Labs starts at Free and Grammarly at Free.
Does AI21 Labs or Grammarly run on more platforms?
AI21 Labs runs on Api, Cloud. Grammarly runs on Web, macOS, Windows, iOS, Android.
Can I use AI21 Labs for free?
Both have a free tier, so you can try either at no cost before committing.
What is AI21 Labs best used for?
AI21 Labs is most often used for running long-context tasks on the jamba model family, building and optimising production ai agents with maestro, routing between models to control cost and accuracy, long-horizon agentic tasks needing stateful workspaces. Of those, running long-context tasks on the jamba model family and building and optimising production ai agents with maestro are not what Grammarly is typically brought in for.
What can AI21 Labs do that Grammarly cannot?
AI21 Labs covers Jamba models, Long context, RAG engine, Writing tools. Grammarly covers Grammar checking, Spelling correction, Punctuation, Clarity suggestions.

Answered from the vendors’ own pages

AI21 Labs: How much do AI21's Jamba Mini and Jamba Large models cost?

Jamba Mini costs $0.2 per 1M input tokens and $0.4 per 1M output tokens. Jamba Large is priced at $2 per 1M input tokens and $8 per 1M output tokens. Both models use usage-based billing with no monthly minimums.

Source
Grammarly: Does Grammarly have a free version?

Yes, Grammarly offers a free tier with basic spelling, grammar, and punctuation checks, tone visibility, and 100 AI prompts per month. The Pro plan ($12/month annual) adds sentence rewriting, plagiarism detection, and 2,000 AI prompts.

Source
AI21 Labs: Does AI21 offer a free trial?

Yes, AI21 provides a free trial with 10 USD in credits for 7 days, no credit card required. The trial grants access to all Foundation models via API and SDK.

Source
Grammarly: What platforms does Grammarly work with?

Grammarly works across 1 million+ apps including Google Docs, Microsoft Word, Outlook, Slack, Gmail, and web browsers. It also integrates with productivity tools like Asana, Jira, Monday.com, Confluence, and HubSpot.

Source
AI21 Labs: How do AI21's custom plans and volume discounts work?

Custom plans with volume discounts are available for enterprises but require contacting sales. These plans can include premium API rate limits, private cloud hosting, priority support, dedicated account managers, and expert consultancy.

Source
Grammarly: Can I use Grammarly offline?

Grammarly requires an internet connection to function, though the browser extension works with some offline text areas. For offline use, the desktop app and browser extensions sync when reconnected.

Source
AI21 Labs: What does AI21 mean by 30% token efficiency savings?

AI21 claims their tokenization delivers approximately 30% more text per token compared to other providers, which can reduce effective costs by roughly 30%. This applies primarily to English-language text averaging 1 word or 6 characters per token.

Source
Grammarly: What is included in the Enterprise plan?

The Enterprise plan includes unlimited team members, dedicated support, custom roles and permissions, data loss prevention, bring-your-own-key encryption, and unlimited AI prompts. Pricing is custom and available by contacting sales.

Source
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