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Amazon Lex vs Plain

Amazon Lex logo

Amazon Lex

Live Chat

AWS conversational AI service

From
Free
Rated
-
Full reviewWebsite
Plain logo

Plain

Customer Support

AI support infrastructure built for B2B teams

From
$35/month
Rated
-
Full reviewWebsite

The short version

  • Only Amazon Lex has a free tier, so it costs nothing to try first.
  • Each has a real cost: Amazon Lex pay-as-you-go model with no standard free tier, only AWS free credits for new customers (6 months, $200 limit); Plain foundation plan limited to 2,000 credits per month may be restrictive for high-volume teams
  • They diverge on capability: Amazon Lex covers Speech recognition, Plain covers Multi-channel consolidation.

Where they differ

Only the attributes on which Amazon Lex and Plain actually diverge.

Attributes where Amazon Lex and Plain differ
AttributeAmazon LexPlain
Starting priceFree$35/month
Pricing modelusage-basedTiered pricing per seat with credit system
Free tierYesNo
PlatformsWeb, AWS CloudWeb, API
CategoryLive ChatCustomer Support
Founded2006Unknown

Identical on both: 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 Amazon Lex

  • Speech recognition
  • Natural language understanding
  • Voice and text
  • Lambda integration
  • AWS services
  • Lambda
  • DynamoDB
  • SNS

Only in Plain

  • Multi-channel consolidation
  • AI agents
  • Workflow automation
  • Sidekick assistant
  • Insights engine
  • Linear and Jira integration
  • Help Center and Knowledge Base
  • API-first extensibility

What people use each for

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

Amazon Lex

  • Chatbot developmentnot Plain
  • Voice-based conversational AInot Plain
  • Natural language understandingnot Plain

Plain

  • Consolidating support from multiple channels into one inboxnot Amazon Lex
  • Automating support workflows with AI agentsnot Amazon Lex
  • Extracting insights and trends from customer conversationsnot Amazon Lex
  • Building custom support solutions with API accessnot Amazon Lex
  • Implementing AI-assisted customer support at scalenot Amazon Lex

Where each one falls short

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

Amazon Lex

  • Pay-as-you-go model with no standard free tier, only AWS free credits for new customers (6 months, $200 limit)
  • Speech requests cost $0.004 each, text requests $0.00075 each, training costs $0.50 per minute
  • Variable costs can accumulate quickly for high-volume applications

Plain

  • Foundation plan limited to 2,000 credits per month may be restrictive for high-volume teams
  • Pricing increases significantly from Foundation to Horizon ($35 to $299 per month)
  • No published pricing for Frontier (custom) plan
  • Additional seat costs ($99 per seat) add up for larger teams
  • Credit-based system requires monitoring usage to avoid overages

Pricing, plan by plan

Amazon Lex

Free
  • Standard Usage$0.004/per speech request
    • Speech requests at $0.004 each
  • Text Requests$0.00075/per text request
    • Text requests at $0.00075 each

Plain

$35/month
  • Foundation$35/month
    • 2,000 credits per month
    • Slack and email channels
    • Ari AI agent
  • Horizon$299/month
    • 15,000 credits per month
    • All Foundation features
    • Microsoft Teams integration
  • Frontier$null/custom
    • Custom credit allowance
    • All Horizon features
    • Discord channels

Which should you pick?

Choose Amazon Lex if

  • You need speech recognition.
  • You want to start without paying.
  • You work on Web, AWS Cloud.
  • You also want natural language understanding.
Amazon Lex review

Choose Plain if

  • You need multi-channel consolidation.
  • You work on Web, API.
  • You also want ai agents.
Plain review

Questions people ask

Is Amazon Lex or Plain better?
Neither clearly leads. Amazon Lex starts at Free and Plain at $35/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Amazon Lex or Plain?
Amazon Lex has a free tier; the other does not. Paid plans start at Free for Amazon Lex and $35/month for Plain.
Does Amazon Lex or Plain run on more platforms?
Amazon Lex runs on Web, AWS Cloud. Plain runs on Web, API.
Can I use Amazon Lex for free?
Yes. Amazon Lex has a free tier, so you can try it without paying. Plain starts at $35/month.
What is Amazon Lex best used for?
Amazon Lex is most often used for chatbot development, voice-based conversational ai, natural language understanding. Of those, chatbot development and voice-based conversational ai are not what Plain is typically brought in for.
What can Amazon Lex do that Plain cannot?
Amazon Lex covers Speech recognition, Natural language understanding, Voice and text, Lambda integration. Plain covers Multi-channel consolidation, AI agents, Workflow automation, Sidekick assistant.

Answered from the vendors’ own pages

Amazon Lex: How much does Amazon Lex cost?

Amazon Lex charges $0.004 per speech request and $0.00075 per text request with no upfront commitments or minimum fees required.

Source
Plain: What is included in the Foundation plan?

The Foundation plan ($35/month per seat) includes 2,000 credits per month, support for Slack and email, Ari AI agent, Linear and Jira integrations, and Help Center access. Up to 5 seats are included.

Source
Amazon Lex: Is there a free tier for Amazon Lex?

Yes, new AWS customers receive 10,000 text requests and 5,000 speech requests per month free for the first year. Additional $200 in AWS Free Tier credits are available for new customers as of July 15, 2025, with all credits expiring within 12 months.

Source
Plain: Can I use Plain with Microsoft Teams?

Yes, Microsoft Teams integration is available on the Horizon plan ($299/month) and higher.

Source
Amazon Lex: What is the example monthly cost for Amazon Lex?

For 8,000 speech requests ($32) and 2,000 text requests ($1.50), the approximate monthly total is $33.50, though actual costs vary based on usage volume.

Source
Plain: Is there a free trial for Plain?

Yes, Plain offers a 7-day free trial with no credit card required. You can also get 50% discount through their startup program.

Source
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