The Short Version
Vapi, Retell AI, Bland, and Synthflow are all platforms for building AI phone agents. None is best for everyone. They differ in how they charge, how much control they give developers, which compliance options they offer, and who they are designed for.
- Vapi: a developer platform where you choose the speech, AI model, and voice providers, and pay a platform fee plus those providers' costs.
- Retell AI: a voice agent platform with published per-minute pricing for each component and a broad set of compliance options.
- Bland: an all-in per-minute rate that bundles the AI model, speech recognition, and voice, with plan-based call caps.
- Synthflow: positioned for enterprises and contact centers, with a visual flow designer and enterprise contracts.
Pricing below is what each vendor listed on its own pricing page in October 2026. It changes often, so confirm current rates before you decide.
Side-by-Side Overview
| Vapi | Retell AI | Bland | Synthflow | |
|---|---|---|---|---|
| Pricing model | $0.05/min hosting plus provider costs at cost | Per-minute components; vendor states $0.07 to $0.31/min total | $0.12 to $0.14/min all-in for AI, speech, and voice on listed plans; telephony separate | Enterprise contracts from $30,000/year |
| Free start | $5 in credits | $10 in credits | Start plan, no platform fee | Free to start building |
| Included concurrency | 4 to 30 calls by tier; more at $10/line/month | First 20 free; more at $8/month each | 10 on Start, 50 on Build, custom on Enterprise | Planned per contract |
| HIPAA / BAA | Add-on at $2,000/month including BAA | Listed, along with SOC 2 and custom DPA | Enterprise plan | Listed, with SOC 2 and ISO 27001 |
| Best fit | Developers who want control over every component | Teams wanting flexibility with clear pricing | Teams that want simple all-in pricing, often for calling at volume | Larger organizations and contact centers |
Vapi
Vapi is built for developers. You assemble the agent from providers you choose, such as a speech-to-text service, an AI model, and a voice, and Vapi orchestrates the call. Its pricing page lists a $0.05 per minute hosting fee, with model and voice providers passed through at cost, plus telephony.
Strengths: fine-grained control, a wide choice of providers, and a strong fit for custom integrations. Watch for: you need technical skill to configure and maintain it, and HIPAA support is a paid add-on. See Vapi vs. Retell AI for a closer comparison.
Retell AI
Retell AI provides voice infrastructure and agent tooling with a published price for each part: voice infrastructure, text-to-speech, the AI model you select, and telephony. The vendor states a total range of $0.07 to $0.31 per minute depending on those choices, and lists HIPAA with BAAs, SOC 2 certification, and custom DPAs.
Strengths: transparent component pricing, generous included concurrency, and broad compliance options. Watch for: costs vary widely with your model and voice choices, so price your actual configuration.
Bland
Bland charges an all-in rate per minute of talk time that covers the AI model, speech recognition, and voice, with telephony billed separately. Its listed plans cap daily and hourly calls and concurrency, with higher limits, warm transfers, guardrails, and compliance options such as BAAs on Enterprise.
Strengths: simple, predictable per-minute pricing and a focus on calling at scale. Watch for: check which features you need are Enterprise-only, and review plan caps against your volume. See Bland vs. Synthflow.
Synthflow
Synthflow positions itself as enterprise voice AI, with a visual Flow Designer, in-house telephony, and forward-deployed engineers for launch. Its pricing page lists enterprise contracts starting at $30,000 a year, priced by volume, concurrency, integrations, and security needs, and highlights SOC 2, HIPAA, GDPR, and ISO 27001.
Strengths: enterprise support, a visual builder, and implementation help. Watch for: the contract minimum puts it out of reach for most small businesses.
What About ElevenLabs?
ElevenLabs is best known for natural-sounding voices, and its Agents platform is a full voice agent product as well. It lists $0.08 per additional minute plus AI model costs, with plans that include minutes. Many teams also use ElevenLabs voices inside other platforms. See our ElevenLabs Agents business guide.
How to Choose
- Start with the call, not the platform. Write down the call types, integrations, transfer rules, and compliance needs.
- Price your real configuration. Estimate monthly minutes, average call length, concurrency at peak, and any compliance add-ons.
- Run the same test calls on two finalists, including interruptions, unclear answers, unavailable time slots, and transfer requests.
- Check operations: how easily your team can test changes, review transcripts, and roll back a bad update.
- Pilot before committing.
Our guide on how to choose an AI calling platform includes a scoring framework.
The Platform Is Only Part of the Result
Most of the difference between a voice agent that books jobs and one that frustrates callers comes from call design, integrations, testing, and transcript review, not the platform logo. Any of these platforms can produce a poor agent if those pieces are skipped.
Bottom Line
Choose Vapi for developer control, Retell AI for flexible components with clear pricing and compliance options, Bland for simple all-in pricing at volume, and Synthflow if you are an enterprise with a budget to match. Then test your own calls before you commit. If you want a partner to build on whichever platform fits, see our Vapi implementation and Retell AI implementation services.
Official documentation
Platform capabilities and implementation details can change. These official references help readers verify the guidance in this article.
- Vapi pricing from Vapi
- Retell AI pricing from Retell AI
- Bland AI pricing from Bland AI
- Synthflow pricing from Synthflow
- ElevenLabs Agents pricing from ElevenLabs