Decagon
AI Agents
Customer service AI agents that run across chat, email and voice.
✓ Verified
No reviews yet
Custom pricing, typically per resolved conversation
Sierra alternatives
20 comparable options, ranked by how closely they match Sierra's category, pricing model and popularity. We list where each one is genuinely stronger.
How to choose
- • If you need a free tier to start, look for the free-tier badge — it means you can test the workflow before paying.
- • If you need to embed it in your own product, check the API availability row.
- • If data residency matters, check whether the tool is open source or self-hostable.
- • If you are switching from Sierra, the pricing note shows whether the entry plan is comparable.
xAI API Platform
AI Assistants
xAI's developer platform offering the Grok model family over a REST API.
✓ Verified
No reviews yet
Per-token pricing; no monthly minimum
Claude Code
Code Assistants
Anthropic's terminal-first coding agent for whole-repository work.
✓ Verified
No reviews yet
Included with Claude Pro and Max; API usage priced per token
Intercom Fin
AI Chatbots
Customer support agent that resolves tickets using your own help centre.
✓ Verified
No reviews yet
$0.99 per resolution; bundled from $29/seat/mo
DALL·E 3
Image Generation
OpenAI's text-to-image model, reachable inside ChatGPT.
✓ Verified
No reviews yet
Included with ChatGPT Plus; API priced per image
Cartesia
AI Voice
Low-latency speech API built for real-time voice agents.
✓ VerifiedFree tier
No reviews yet
Free tier available; usage priced per character
Deepgram
AI Voice
Speech-to-text and voice agent APIs with very low latency.
✓ VerifiedFree tier
No reviews yet
Pay-as-you-go per minute of audio
ChatGPT
AI Assistants
General-purpose AI assistant with the widest capability spread of any consumer product.
✓ VerifiedFree tier
★ 5.0
(1)
Free tier available; Plus $20/mo, Pro $200/mo
Claude
AI Assistants
Anthropic's assistant, favoured for long-context reasoning and careful, structured writing.
✓ VerifiedFree tier
No reviews yet
Free tier available; Pro $20/mo; API priced per token
Google Gemini
AI Assistants
Google's multimodal assistant, deeply integrated into Search, Docs and Workspace.
✓ VerifiedFree tier
No reviews yet
Free tier available; Google AI Pro $19.99/mo, AI Ultra $249.99/mo
Microsoft Copilot
AI Assistants
AI woven into Windows, Office and Microsoft 365 with enterprise compliance.
✓ VerifiedFree tier
No reviews yet
Included with Microsoft 365; Copilot Pro $20/mo
Perplexity
AI Research
Answer engine that cites every source, built for research rather than chat.
✓ VerifiedFree tier
No reviews yet
Free tier available; Pro $20/mo or $200/mo; Enterprise $40/seat/mo
Grok
AI Assistants
xAI's assistant with real-time access to X posts and a strong reasoning focus.
✓ VerifiedFree tier
No reviews yet
Free tier available; SuperGrok $30/mo; SuperGrok Heavy $300/mo
Le Chat
AI Assistants
Mistral's fast European assistant, with a strong open-weight model family behind it.
✓ VerifiedOpen sourceFree tier
No reviews yet
Free tier available; Le Chat Pro $14.99/mo
DeepSeek
AI Assistants
Open-weight reasoning models with an unusually generous free API.
✓ VerifiedOpen sourceFree tier
No reviews yet
Free web and app; API priced per token
Grammarly
AI Writing
Writing assistance across every browser tab and desktop app.
✓ VerifiedFree tier
No reviews yet
Free tier available; Premium $12/mo; Pro $36/mo
Jasper
AI Writing
Marketing-focused AI writing with brand voice and campaign templates.
✓ Verified
No reviews yet
Business $39/seat/mo; Pro $59/seat/mo; Enterprise custom
Copy.ai
AI Writing
Go-to-market copy generation for sales, ads and email sequences.
✓ Verified
No reviews yet
Free trial; Pro $29/mo; Enterprise custom
Notion AI
AI Writing
AI embedded in the workspace where notes, docs and wikis already live.
✓ Verified
No reviews yet
Included with Business and Enterprise; AI add-on $10/member/mo
Writesonic
AI Writing
SEO-focused content and bulk article generation.
✓ VerifiedFree tier
No reviews yet
Individual $20/mo; Business $130/mo for 3 seats
Comparing two specific options?
Open any two listings side by side with a full feature and pricing table.
Open the comparison tool