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HARPA AI vs Sider

Two fact sheets from our own research, side by side — pricing, platforms, API access and status re-checked by us rather than quoted from the vendors. Sider publishes a starting price ($10); HARPA AI does not. Both have a free tier.

HARPA AIBrowser extension pairing chat models with web page automationSiderBrowser sidebar that puts GPT, Claude, Gemini, and other models next to any page you're reading.

Side by side

FactHARPA AISider
CategoryBrowser Extensions & CopilotsBrowser Extensions & Copilots
Pricing modelFreemiumFreemium
Starts at—$10 month
Public APINoNo
PlatformsWeb, Chrome ExtWeb, Chrome Ext, Windows, macOS, iOS, Android
CompanyHARPA AI TECHNOLOGIES LLCSider
Last verifiedSep 6, 2026Sep 1, 2026

What our research says

HARPA AI

The strongest option if you want one extension that both discusses a page and acts on it, and it earns its price only if you actually build repeatable web workflows. For plain summaries and a chat sidebar, cheaper single-purpose extensions do the same job.

Pros

  • Commands run against the live DOM, so they work on pages behind a login
  • Bring-your-own-key and web-session modes keep running costs down
  • Registered EU entity with GDPR and ISO 27001 claims, unusual for an extension
  • Lifetime licence exists for people who refuse subscriptions

Cons

  • The command builder has a genuine learning curve
  • Token metering makes monthly spend hard to forecast
  • No developer API of its own, despite the automation positioning
  • Automations break when target sites change their markup

Sider

Sider puts a chat panel on top of whatever page you're on, so you can ask about an article or PDF without copying it into a separate tab. The catch is that heavier use beyond the free daily cap needs a paid tier, and pricing quoted across review sites is inconsistent, so the entry price is worth confirming before committing.

Pros

  • Works as a sidebar on any web page rather than a separate chat tab
  • Routes one prompt to several models (GPT, Claude, Gemini, DeepSeek, Grok)
  • Ships native apps for iOS, Android, Windows, and Mac plus browser extensions
  • Can chat with PDFs and YouTube videos, not just plain text

Cons

  • Free tier is capped at a small number of daily uses
  • Independent pricing write-ups disagree on exact plan costs depending on where you check
  • No public API for developers

Which one fits

Choose HARPA AI if you need

  • Sales and research work that repeats the same extract-then-summarise loop across many pages
  • People who prefer bringing their own model API keys over another per-seat AI subscription
  • Watching pages for price or stock changes and firing alerts

Choose Sider if you need

  • Reading and summarizing long articles or PDFs without leaving the page
  • Comparing answers from several models in one panel
  • People who want one subscription instead of several separate chatbot logins

More comparisons

All HARPA AI alternatives →Browse all Browser Extensions & Copilots →