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Plain vs Siena AI

Features, pricing, ratings, and pros and cons, side by side.

Plain logo

Plain

AI-powered support platform for B2B teams, unifying Slack, email and chat in one workspace

Free trial
Visit websiteView details

Verdict

Plain is listed under Help Desk Software and Siena AI under AI Customer Support. Neither has a free plan. Only Plain offers an API.

Best overall

Plain

  • B2B SaaS companies
  • Support teams
  • Customer success teams
  • Startups

Choose Plain if

  • You want a tool built for Teams that support business customers through shared Slack or Teams channels and want AI triage, routing and an API-first setup.
  • Built around B2B support, with Slack, Teams and Discord channels alongside email and chat.
  • Ari and Sidekick AI agents are included from the entry plan.

Choose Siena AI if

  • You want a tool built for brands with high ticket volume on Shopify and a helpdesk such as Gorgias or Zendesk that want to automate order, return and subscription requests.
  • Wide set of named integrations across helpdesks, subscriptions, returns, shipping and reviews.
  • Covers support, shopping, social, reviews and QA agents on one platform.
Best for beginners
Plain
Best for business
Siena AI

Features

17 features compared.

  • Multichannel Inbox
    Plain
    Available
    Siena AI
    Not available
  • Ari AI Agent
    Plain
    Available
    Siena AI
    Not available
  • Sidekick
    Plain
    Available
    Siena AI
    Not available
  • Workflows
    Plain
    Available
    Siena AI
    Not available
  • Insights
    Plain
    Available
    Siena AI
    Not available
  • Bring Your Own Agents
    Plain
    Available
    Siena AI
    Not available
  • API
    Plain
    Available
    Siena AI
    Not available
  • Help Center and Knowledge Base
    Plain
    Available
    Siena AI
    Not available
  • Customer Service Agent
    Plain
    Not available
    Siena AI
    Available
  • Post-Purchase Workflows
    Plain
    Not available
    Siena AI
    Available
  • Subscription Management
    Plain
    Not available
    Siena AI
    Available
  • Shopping Agent
    Plain
    Not available
    Siena AI
    Available
  • Social Agent
    Plain
    Not available
    Siena AI
    Available
  • Reviews Agent
    Plain
    Not available
    Siena AI
    Available
  • QA Agent and Topics Explorer
    Plain
    Not available
    Siena AI
    Available
  • Agent Assist
    Plain
    Not available
    Siena AI
    Available
  • Guardrails and Controls
    Plain
    Not available
    Siena AI
    Available

Pricing

Plans as listed by each vendor. Check their sites for current prices.

  • Pricing model
    Plain
    Free trial
    Siena AI
    Paid
  • Free plan
    Plain
    No
    Siena AI
    No
  • Starting price
    Plain
    $45
    Siena AI
    $750
  • Plans
    Plain
    3 plans
    Siena AI
    2 plans

Plain plans

  • Foundation

    Most popular

    $45/user/mo

    Small teams getting started with support

    • 1,000 credits/month
    • Sidekick
    • Ari
    • AI workflows
    • Slack
    • email and in-app channels
    • Linear and Jira integrations
    • Help Center
    • Knowledge Base

  • Horizon

    $99/user/mo

    Growing teams with more complex workflows

    • 2,500 credits/month
    • Microsoft Teams
    • SLAs and business hours
    • escalation paths
    • CRM integrations
    • reporting themes
    • AI suggested responses

  • Frontier

    Custom/custom

    Larger organizations needing governance and control

    • Custom credits
    • multiple workspaces
    • custom contracting
    • advanced security
    • SSO and SCIM
    • HIPAA
    • white glove onboarding
    • dedicated customer success manager

Siena AI plans

  • Platform

    Most popular

    $750/month

    Flat fee for access to the core AI system

    • Core AI system
    • unlimited testing environment
    • brand voice and guardrails
    • SAML SSO
    • audit logs
    • SOC 2 Type II

  • Automation Pack

    $0.90/ticket

    Usage charge per automated ticket

    • Billed per automated ticket
    • human handoff
    • business rules

Our ratings

Scored out of 10 by the Finder Atlas editorial team. Last reviewed November 2026.

Plain
7.9overall
Siena AI
7.8overall

Plain leads in 3 categories and Siena AI in 2.

  • Ease of Use

    Plain leads by 0.2
    Plain
    8.0
    Siena AI
    7.8

  • Feature Depth

    Siena AI leads by 0.3
    Plain
    8.2
    Siena AI
    8.5

  • Value for Money

    Plain leads by 0.1
    Plain
    7.3
    Siena AI
    7.2

  • Performance & Speed

    Siena AI leads by 0.2
    Plain
    7.8
    Siena AI
    8.0

  • Documentation & Support

    Plain leads by 0.4
    Plain
    8.0
    Siena AI
    7.6

Scores weigh documented features, plan value, platform coverage, integrations and user feedback. A missing score means we have not rated that area yet.

Pros and cons

Plain

Pros

  • Built around B2B support, with Slack, Teams and Discord channels alongside email and chat.
  • Ari and Sidekick AI agents are included from the entry plan.
  • API-first design allows custom workflows and embedding.
  • 7-day trial without a credit card, plus a 50% startup discount.
  • Enterprise options include SSO, SCIM and HIPAA on the Frontier plan.

Cons

  • No permanently free plan; paid plans start at $45 per user per month.
  • AI usage is metered in credits (1,000 per month on Foundation), which makes costs harder to predict.
  • Microsoft Teams and CRM integrations require the $99 Horizon plan.
  • No iOS or Android app was found.

Siena AI

Pros

  • Wide set of named integrations across helpdesks, subscriptions, returns, shipping and reviews.
  • Covers support, shopping, social, reviews and QA agents on one platform.
  • Transparent base pricing: $750/month plus $0.90 per automated ticket.
  • Enterprise controls including SOC 2 Type II, SAML SSO and audit logs.
  • Funded company with a $17M Series A and a customer list of recognizable DTC brands.

Cons

  • $750/month minimum platform fee is high for small stores.
  • No free tier or self-serve trial listed.
  • Implementation and support pricing is not published.
  • Focused on e-commerce brands, so less suited to B2B or non-commerce support.

Platforms

  • Web
    Plain
    Supported
    Siena AI
    Supported
  • Windows
    Plain
    Not supported
    Siena AI
    Not supported
  • macOS
    Plain
    Not supported
    Siena AI
    Not supported
  • iOS
    Plain
    Not supported
    Siena AI
    Not supported
  • Android
    Plain
    Not supported
    Siena AI
    Not supported
  • API
    Plain
    Supported
    Siena AI
    Not supported
  • Browser Extension
    Plain
    Not supported
    Siena AI
    Not supported

Integrations

Plain

6 integrations
  • Slack
  • Microsoft Teams
  • Discord
  • Linear
  • Jira
  • PagerDuty

Siena AI

18 integrations
  • Zendesk
  • Gorgias
  • Intercom
  • Dixa
  • Gladly
  • Kustomer
  • Shopify
  • Stripe
  • Recharge
  • Skio
  • Ordergroove
  • Loop Returns
  • AfterShip
  • ShipBob
  • Klaviyo
  • Okendo
  • Yotpo
  • Slack

Company

  • Company
    Plain
    Plain
    Siena AI
    Siena AI
  • Founded
    Plain
    2020
    Siena AI
    2022
  • Headquarters
    Plain
    London, United Kingdom
    Siena AI
    New York, NY
  • Listing
    Plain
    Claimed
    Siena AI
    Claimed

Frequently asked questions

Is Plain better than Siena AI?

It depends on your workflow. Plain is built for Teams that support business customers through shared Slack or Teams channels and want AI triage, routing and an API-first setup. Siena AI is built for brands with high ticket volume on Shopify and a helpdesk such as Gorgias or Zendesk that want to automate order, return and subscription requests.

What are the key feature differences between Plain and Siena AI?

Plain: AI-powered support platform for B2B teams, unifying Slack, email and chat in one workspace. Siena AI: AI customer service agents that resolve e-commerce support tickets in your brand voice.

Does Plain or Siena AI have a free plan?

Neither has a free plan. Both Plain and Siena AI are paid products.

Which is cheaper, Plain or Siena AI?

Plain starts at $45 and Siena AI starts at $750. See the pricing table above for what each tier includes.