Side-by-side comparison · Sales & Customer Support
Retell AI vs Sierra vs Yoodli
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: 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.
Pick it if: Professionals, founders and sales teams who want to practise pitches, presentations and hard conversations out loud.
Overview
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| In one line | 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. | AI speaking coach: role-play pitches and hard conversations and get feedback on delivery. |
| Pricing model | Paid | Paid | Freemium |
| Starting price | About $0.07–$0.31/min | See website | $8/mo |
| Free plan | No | No | Yes |
| Works with Claude Code | Yes | No | No |
Rating breakdown
Our scores out of 5. The higher bar in each row is highlighted.
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Overall rating | 4.1 | 3.9 | 4.1 |
| Ease of useHow quickly someone non-technical gets value from it. | 3.5 | 3.0 | 4.5 |
| FeaturesHow completely it covers its own job, and how well the pieces fit together. | 4.5 | 4.5 | 4.0 |
| Output qualityHow good the results are before you fix them. | 4.5 | 4.5 | 4.0 |
| Value for moneyWhat you get for the price, including the free plan. | 4.0 | 3.0 | 4.0 |
| Speed & reliabilityHow fast it is and how often it falls over. | 4.0 | 4.5 | 4.0 |
Feature comparison
A tick means it does this today. A dash means we haven't checked.
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Access & platform | |||
| Free plan | No | No | Yes |
| Mobile app | – | – | – |
| Desktop app | – | – | – |
| Browser extension | – | – | – |
| API access | 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 | Yes |
| Understands images | – | – | – |
| Makes images | No | No | No |
| Makes video | No | No | No |
| Writes code | – | – | No |
| Runs agents or automations | Yes | Yes | – |
| Learns your brand or style | – | Yes | – |
| Works in many languages | Yes | Yes | Yes |
| Capabilities score | 7/ 17 | 7/ 17 | 6/ 17 |
Pricing
Plans as listed on each vendor's site when we last checked. Confirm before you buy.
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Plans | 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. | Starter Free Trying it once or twice. |
Enterprise Custom High call volumes and compliance needs. | ProOur pick $8/mo billed yearly Individuals practising most weeks. | ||
Advanced $20/mo billed yearly Heavy individual users who want privacy. | |||
Business Custom per seat, billed yearly Sales and training teams. | |||
Enterprise Custom Very large organisations. | |||
| Which plan to pick | 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. | Individuals should take Pro on the yearly plan; it is cheap and ten sessions a week is plenty. Teams wanting their own sales scenarios need Business. |
Key features
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Standout features |
|
|
|
Pros and cons
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Pros |
|
|
|
| Cons |
|
|
|
Who each one is for
| Attribute | Retell AI | Sierra | Yoodli |
|---|---|---|---|
| Best for |
|
|
|
| You'll find it used by |
|
|
|
Questions people ask
Which is better, Retell AI, Sierra or Yoodli?
They tie on our overall rating (Retell AI 4.1/5, Sierra 3.9/5 and Yoodli 4.1/5). 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. Yoodli is best for rehearsing a pitch or presentation and cutting filler words and rambling.
Which is cheaper, Retell AI, Sierra or Yoodli?
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. Yoodli: There's a free plan, and paid plans start at $8/mo.
Which is easier to use, Retell AI, Sierra or Yoodli?
Yoodli rates highest for ease of use in our scores. Professionals, founders and sales teams who want to practise pitches, presentations and hard conversations out loud.
How we compare
Ratings are our own, from using each tool, across ease of use, features, output quality, value for money, speed & reliability.
Swap in another tool
More tools from Sales & Customer Support in the library.
