Softwr

Live Chat · head to head

Amazon Lex vs Rasa

Amazon Lex logo

Amazon Lex

Live Chat

AWS conversational AI service

From
Free
Rated
-
Full reviewWebsite
Rasa logo

Rasa

Live Chat

Open-source framework for building conversational AI

From
Free
Rated
-
Full reviewWebsite

The short version

  • 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); Rasa free Developer Edition caps conversations at 1,000 external or 100 internal per company per month
  • They diverge on capability: Amazon Lex covers Speech recognition, Rasa covers NLU engine.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where Amazon Lex and Rasa differ
AttributeAmazon LexRasa
Pricing modelusage-basedfreemium
PlatformsWeb, AWS CloudOn-premise, Cloud deployment, Docker, Kubernetes
Founded20062016

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

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 Rasa

  • NLU engine
  • Dialogue management
  • Multi-language support
  • Testing tools
  • Slack
  • Teams
  • Custom channels
  • API

What people use each for

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

Amazon Lex

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

Rasa

  • Developers self-hosting an open source conversational AI framework before needing enterprise 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

Rasa

  • Free Developer Edition caps conversations at 1,000 external or 100 internal per company per month
  • Rasa Pro and the Business Plan (Pro plus Studio) are not priced on the site and require contacting sales

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

Rasa

Free
  • Free Developer EditionFree
    • One bot per company
    • Up to 1,000 external conversations per month or 100 internal conversations per month
    • Free Rasa license for local or production use
  • Rasa Pro$undefined/mo
    • Pro-code framework with CALM dialogue understanding
    • Language-agnostic NLU, enterprise search, multi-LLM management
    • Kubernetes support
  • Enterprise$undefined/mo
    • Full access to Rasa Platform and Premium Support
    • 24/7/365 support with Customer Success Manager
    • Business reviews and guidance

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 Rasa if

  • You need nlu engine.
  • You want to start without paying.
  • You work on On-premise, Cloud deployment, Docker, Kubernetes.
  • You also want dialogue management.
Rasa review

Questions people ask

Is Amazon Lex or Rasa better?
Neither clearly leads. Amazon Lex starts at Free and Rasa at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Amazon Lex or Rasa?
Amazon Lex starts at Free and Rasa at Free.
Does Amazon Lex or Rasa run on more platforms?
Amazon Lex runs on Web, AWS Cloud. Rasa runs on On-premise, Cloud deployment, Docker, Kubernetes.
Can I use Amazon Lex for free?
Both have a free tier, so you can try either at no cost before committing.
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 Rasa is typically brought in for.
What can Amazon Lex do that Rasa cannot?
Amazon Lex covers Speech recognition, Natural language understanding, Voice and text, Lambda integration. Rasa covers NLU engine, Dialogue management, Multi-language support, Testing tools.

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
Rasa: Does Rasa offer a free version?

Yes. Rasa offers a free Developer Edition with one bot per company, up to 1,000 external conversations per month, and free community support.

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
Rasa: What support is included with Rasa's free tier?

The free tier includes community forum support with responses from Rasa community members. Paid tiers add premium support with enhanced response times.

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
Rasa: What is the difference between Rasa Pro and Enterprise?

Rasa Pro includes the pro-code framework with advanced NLU and multi-LLM management. Enterprise adds full platform access, 24/7 support, dedicated Customer Success Manager, and business reviews.

Source
Share

Related pages

More on Amazon Lex

More on Rasa

Keep looking

Other head to heads