The Retell AI Alternative
With One All-Inclusive Rate
Phone Stack is a Retell AI alternative that bundles voice AI, telephony, transcription, campaign tooling, and compliance into one all-inclusive rate — from $0.18/minute at the Enterprise volume tier — instead of Retell's component stack ($0.055/min voice base plus separate TTS and LLM charges). Setup is zero-code chat training with ~320ms native speech-to-speech latency, and every account starts with 30 free minutes.
No credit card required.
Why teams evaluating Retell AI look at Phone Stack
Retell AI is a genuinely strong developer platform — well-documented APIs, granular control over your STT, TTS, and LLM choices, and the fastest-growing company in the category. If you're an engineering team building a custom voice product, it deserves a place on your shortlist.
The trade-off is that Retell sells you the voice pipeline, not the operation around it. Pricing is assembled from components — a per-minute voice base plus separate TTS and LLM charges that vary with every model and voice decision — and campaign dialing, supervisor monitoring, and compliance workflows are yours to build. Phone Stack takes the opposite approach: a complete AI-run call center platform with one all-inclusive rate, a built-in outbound campaign engine, Listen Live and Barge In supervision, and TCPA tooling — trained via chat, no code required. See how it stacks up against the rest of the field on our full comparison page.
Retell AI pricing vs Phone Stack: the math at 3,000 minutes/month
Retell prices each pipeline component separately, so your true per-minute cost depends on which TTS voice and LLM you pick. Here's the realistic range. Pricing verified 2026-06.
| Retell AI component | Rate | At 3,000 min/mo |
|---|---|---|
| Voice engine base | $0.055/min | $165 |
| TTS (voice provider) | $0.015–$0.04/min | $45–$120 |
| LLM (model choice) | $0.003–$0.08/min | $9–$240 |
| Retell AI total | ~$0.073–$0.175/min | $219–$525/mo |
| Phone Stack — everything included | $0.18/min (Enterprise volume rate) | $540/mo |
Read that honestly: a bare-bones Retell configuration — cheapest TTS voice, budget LLM — can run as low as ~$219/month for the raw pipeline ($0.055 + $0.015 + $0.003 = $0.073/min). But configure it the way most production deployments do, with a premium voice and a capable model, and you're at ~$0.175/min — $525/month, within $15 of Phone Stack's $540. The difference is what that money buys. Retell's figure covers the voice pipeline; campaign dialing, voicemail detection, live supervision, compliance tooling, and post-call analysis are still on you to build or buy. Phone Stack's $540 includes all of it, and the rate doesn't move when you change models.
Phone Stack figures use the $0.18/min Enterprise volume rate (10,000 min/mo plan). Self-serve prepaid packages run $0.20–$0.25/min — at the $0.20/min Scale rate, 3,000 minutes is $600/mo, still all-inclusive with no separate STT, TTS, or LLM bills. Retell components per our June 2026 verification: $0.055/min voice base + TTS $0.015–$0.04/min + LLM $0.003–$0.08/min, pay-as-you-go with $10 free credits. Full details on our pricing page.
Phone Stack vs Retell AI: feature by feature
What each platform includes out of the box. Pricing and claims verified 2026-06.
| Feature | Phone Stack | Retell AI |
|---|---|---|
| Pricing model | All-inclusive from $0.18/min | Usage-based (STT + TTS + LLM separate) |
| Voice latency | ~320ms (native S2S) | ~500–800ms |
| Setup | Zero-code, chat training | API / developer required |
| Inbound calls | ||
| Outbound calls | ||
| Campaign engine | ||
| Listen Live | ||
| Barge In | ||
| HIPAA ready | ||
| TCPA compliance | ||
| CRM integrations | Native (HubSpot, GCal, 40+) | Via API |
| Voicemail detection | ||
| Free trial | 30 min free | Limited free tier |
Comparing more platforms? See the full comparison including Bland AI, Vapi, and Synthflow.
When Retell AI is the better choice
We'd rather you pick the right tool than pick us for the wrong job. Retell AI is the better fit when:
- You have developers and want to assemble your own STT, TTS, and LLM stack component by component
- You need automated voice-agent QA tooling like Retell Assure
- You want to experiment cheaply with pay-as-you-go credits before committing
Retell's momentum is real — $50M ARR as of April 2026 — and its Retell Assure automated QA product is a capability Phone Stack doesn't have an equivalent for today. If component-level control of your voice stack is the point of your project, Retell is a strong platform. If you want the phone operation itself — campaigns, supervision, compliance, one bill — that's what Phone Stack is built for.
Switching from Retell AI to Phone Stack
There's no code to rewrite, because there's no required code on the Phone Stack side. The agent logic you've invested in — prompts, flows, knowledge — carries over as plain language. Whether you're running inbound answering or an outbound automated calling operation, the path looks the same:
- 1
Export your agent prompts and flows from Retell
Copy the system prompts, conversation flows, and knowledge content you've built in Retell. This is the substance of your agent — and it transfers, because it's just language describing how the agent should behave.
- 2
Recreate the agent with Phone Stack's chat training
Instead of wiring prompts through an API, you train a Phone Stack agent by chatting with it — paste in your Retell prompt material, describe the goal, and refine conversationally. Most agents take 15–30 minutes to stand up.
- 3
Port your phone numbers or buy new ones
Bring existing numbers over via porting, or buy fresh ones in the dashboard (local numbers $2/mo, toll-free $10/mo) if you'd rather switch instantly and port later.
- 4
Test on your 30 free minutes
Every account starts with 30 free minutes of talk time — enough to call yourself, hear the ~320ms native speech-to-speech latency, and verify the agent handles your real scenarios before anything goes live.
- 5
Go live and supervise in real time
Launch inbound routing or an outbound campaign. Use Listen Live to monitor calls as they happen and Barge In to take over when a conversation needs a human.
Retell AI Alternative FAQs
Common questions from teams comparing Retell AI and Phone Stack.
Hear the difference on a real call
Train an agent via chat, call yourself, and compare it to your Retell build. 30 free minutes, no credit card required.