Side-by-side comparison · Sales & Customer Support
Ada vs Retell AI vs Sierra
Everything that matters when choosing between them, in one place: our rating, what each can do, what they cost, and the trade-offs.
Comparing 3 tools, the maximum.
At a glance
Pick it if: Mid-sized and large businesses with high support volumes that want an AI agent on top of their existing helpdesk.
Pick it if: Service businesses and agencies that want an AI receptionist or phone agent without hiring developers.
Pick it if: Large consumer brands that want an AI agent to handle a big share of their customer conversations end to end.
Overview
| Attribute | Ada | Retell AI | Sierra |
|---|---|---|---|
| In one line | AI agents that resolve customer service requests across chat, email and phone. | AI phone agents that answer calls, book appointments and make outbound calls. | Builds and runs AI customer service agents for big brands, across chat, email and phone. |
| Pricing model | Paid | Paid | Paid |
| Starting price | See website | About $0.07–$0.31/min | See website |
| Free plan | No | No | No |
| Works with Claude Code | Yes | Yes | No |
Rating breakdown
Our scores out of 5. The higher bar in each row is highlighted.
| Attribute | Ada | Retell AI | Sierra |
|---|---|---|---|
| Overall rating | 3.7 | 4.1Winner | 3.9 |
| Ease of useHow quickly someone non-technical gets value from it. | 3.5 | 3.5 | 3.0 |
| FeaturesHow completely it covers its own job, and how well the pieces fit together. | 4.0 | 4.5 | 4.5 |
| Output qualityHow good the results are before you fix them. | 4.0 | 4.5 | 4.5 |
| Value for moneyWhat you get for the price, including the free plan. | 3.0 | 4.0 | 3.0 |
| Speed & reliabilityHow fast it is and how often it falls over. | 4.0 | 4.0 | 4.5 |
Feature comparison
A tick means it does this today. A dash means we haven't checked.
| Attribute | Ada | Retell AI | Sierra |
|---|---|---|---|
| Access & platform | |||
| Free plan | No | No | No |
| Mobile app | – | – | – |
| Desktop app | – | – | – |
| Browser extension | – | – | – |
| API access | Yes | Yes | – |
| Teams & business | |||
| Team workspace | Yes | Yes | Yes |
| Enterprise plan or SSO | Yes | Yes | Yes |
| Connects to other apps | Yes | Yes | Yes |
| Open source or self-hosted | No | No | No |
| AI abilities | |||
| Works with your files | – | Yes | Yes |
| Understands images | – | – | – |
| Makes images | No | No | No |
| Makes video | No | No | No |
| Writes code | – | – | – |
| Runs agents or automations | Yes | Yes | Yes |
| Learns your brand or style | Yes | – | Yes |
| Works in many languages | Yes | Yes | Yes |
| Capabilities score | 7/ 17 | 7/ 17 | 7/ 17 |
Pricing
Plans as listed on each vendor's site when we last checked. Confirm before you buy.
| Attribute | Ada | Retell AI | Sierra |
|---|---|---|---|
| Plans | CustomOur pick Custom Businesses with enough volume to justify an enterprise contract. | Pay as you goOur pick About $0.07–$0.31/min Most small businesses and agencies. | EnterpriseOur pick Custom Large companies with high conversation volumes. |
Enterprise Custom High call volumes and compliance needs. | |||
| Which plan to pick | There's only a custom quote. Ask whether you'll be charged per conversation or per resolution, since per-conversation pricing charges you even when the agent doesn't solve the problem. | Start on pay as you go with the free credits, build one agent for your most common call and test it on your own phone. Talk to sales only once you run thousands of minutes a month. | There is one route: talk to Sierra's sales team. Agree clearly what counts as an outcome you pay for, and what setup and services cost, before you sign. |
Key features
Pros and cons
| Attribute | Ada | Retell AI | Sierra |
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Who each one is for
| Attribute | Ada | Retell AI | Sierra |
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Questions people ask
Which is better, Ada, Retell AI or Sierra?
Retell AI scores highest overall in our ratings (Ada 3.7/5, Retell AI 4.1/5 and Sierra 3.9/5). Ada is best for automating common support conversations and AI support across chat, email and voice. Retell AI is best for AI receptionist for a small business and booking appointments by phone. Sierra is best for high-volume customer service at large brands and AI phone agents that take real actions.
Which is cheaper, Ada, Retell AI or Sierra?
Ada: Pricing isn't published; check the vendor's site for a quote. Retell AI: There's no free plan. Paid plans start at About $0.07–$0.31/min. Sierra: Pricing isn't published; check the vendor's site for a quote.
How we compare
Ratings are our own, from using each tool, across ease of use, features, output quality, value for money, speed & reliability.
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