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Retell AI vs Synthflow
Choose Retell AI if you are in the group its listing names: Teams wanting an all-in per-minute price with a visual builder. Choose Synthflow if you are in the group its listing names: Mid-market and enterprise teams wanting a managed rollout. As of 2026-10-17, Retell AI published pricing: Pay-as-you-go $0.07–$0.31/min for voice agents depending on LLM and voice; Retell voice infra $0.055/min; enterprise custom. Per-minute field: $0.07–$0.31/min (all-in range shown by vendor). Free tier: $10 in free credits. As of 2026-10-17, Synthflow published pricing: Enterprise contracts start at $30,000/year; final pricing scoped by volume, concurrency and integrations. Self-serve per-minute pricing not shown on pricing page checked. Per-minute field: not public. Free tier: not public. We have not placed test calls, so this is not a quality ranking.
Pricing checked (Retell AI) and (Synthflow). Sources stay on the vendor pages.
What each listing says
Retell AI is listed as Developer voice platform, builder type developer. The listing best-for line is: Teams wanting an all-in per-minute price with a visual builder. Features stated: Voice agent builder; 20 concurrent calls on PAYG; choice of LLMs and voices (Retell, ElevenLabs, Minimax, Fish); PII removal; QA tools. As of 2026-10-17, Retell AI published pricing: Pay-as-you-go $0.07–$0.31/min for voice agents depending on LLM and voice; Retell voice infra $0.055/min; enterprise custom. Per-minute field: $0.07–$0.31/min (all-in range shown by vendor). Free tier: $10 in free credits. Source: https://www.retellai.com/pricing.
Synthflow is listed as Enterprise voice AI, builder type managed. The listing best-for line is: Mid-market and enterprise teams wanting a managed rollout. Features stated: No-code voice agents; native telephony or SIP; CRM/calendar integrations (HubSpot, Salesforce, GoHighLevel, Cal.com); MSA/DPA support. As of 2026-10-17, Synthflow published pricing: Enterprise contracts start at $30,000/year; final pricing scoped by volume, concurrency and integrations. Self-serve per-minute pricing not shown on pricing page checked. Per-minute field: not public. Free tier: not public. Source: https://synthflow.ai/pricing.
Retell AI is listed under Developer voice platform. Synthflow is listed under Enterprise voice AI. These are different product types. The table compares published facts. It does not crown a winner across categories.
Pricing
Retell AI
Pricing model derived from the published text: per minute.
| Plan | Price | Included | Overage |
|---|---|---|---|
| Pay as you go | $0.07–$0.31/min | $10 free credits; 20 concurrent calls | Depends on LLM and voice |
| Retell voice infra | $0.055/min | — | Component of the per-minute total |
| Enterprise | Custom | — | — |
Synthflow
Pricing model derived from the published text: monthly or annual plan, no public per-minute rate.
| Plan | Price | Included | Overage |
|---|---|---|---|
| Enterprise | from $30,000/year | Scoped by volume and concurrency | — |
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Side by side
| Attribute | Retell AI [1] | Synthflow [2] |
|---|---|---|
| Category | Developer voice platform | Enterprise voice AI |
| Builder | developer | managed |
| Pricing model | per minute | monthly or annual plan, no public per-minute rate |
| Starting price | $0 to start | not public |
| Per minute | $0.07–$0.31/min (all-in range shown by vendor) | not public |
| Free tier | $10 in free credits | not public |
| Phone numbers | yes | yes |
| Compliance stated | not stated | MSA/DPA support |
| Pricing detail | Pay-as-you-go $0.07–$0.31/min for voice agents depending on LLM and voice; Retell voice infra $0.055/min; enterprise custom. | Enterprise contracts start at $30,000/year; final pricing scoped by volume, concurrency and integrations. Self-serve per-minute pricing not shown on pricing page checked. |
| Best for | Teams wanting an all-in per-minute price with a visual builder | Mid-market and enterprise teams wanting a managed rollout |
| Verified from each vendor's pricing page. Unverified amounts are omitted. | ||
Cost at a stated volume
| Monthly minutes | Retell AI | Synthflow |
|---|---|---|
| 500 | $35.00 (Pay as you go (low end of $0.07–0.31)) | not computable from public pricing |
| 2,000 | $140 (Pay as you go (low end of $0.07–0.31)) | not computable from public pricing |
Cheapest published plan at each volume. Where the platform does not include models or telephony, we add our default stack of $0.040/min (see the calculator). Per-call and per-customer plans are not in this estimate. This is not a quote.
Where the listings differ
- Category: Retell AI — Developer voice platform. Synthflow — Enterprise voice AI.
- Builder: Retell AI — developer. Synthflow — managed.
- Pricing model: Retell AI — per minute. Synthflow — monthly or annual plan, no public per-minute rate.
- Starting price: Retell AI — $0 to start. Synthflow — not public.
- Per minute: Retell AI — $0.07–$0.31/min (all-in range shown by vendor). Synthflow — not public.
- Free tier: Retell AI — $10 in free credits. Synthflow — not public.
- Compliance stated: Retell AI — not stated. Synthflow — MSA/DPA support.
- Best for: Retell AI — Teams wanting an all-in per-minute price with a visual builder. Synthflow — Mid-market and enterprise teams wanting a managed rollout.
Categories: Developer voice platform · Enterprise voice AI.
Our test notes
Not tested. We have not placed test calls with Retell AI or Synthflow, so this page makes no claim about latency, interruption, transfer, or call quality. The method we would use is on the methodology page. Until those calls exist, the comparison is published pricing and stated features only.
More comparisons
Retell AI alternatives · Synthflow alternatives
FAQ
Which is cheaper, Retell AI or Synthflow?
At 2,000 minutes a month, using each vendor's cheapest published plan and our default model stack only where the plan does not include models and telephony: Retell AI: $140 on Pay as you go (low end of $0.07–0.31). Synthflow: not computable from a public minute plan. Checked 2026-10-17. This is an estimate from published list prices, not a quote. Compare per-call and per-customer plans on their pricing rows. A per-minute estimate does not apply to those.
Do Retell AI and Synthflow have a free tier?
Retell AI: $10 in free credits. Synthflow: not public. Checked 2026-10-17 and 2026-10-17.
Have you tested Retell AI against Synthflow?
No. We have not placed test calls. This page does not claim a latency, quality, or accuracy winner. See the methodology.