AssemblyAI vs Synthflow — Pricing, Plans, and Verified Costs (2026)
AssemblyAI starts at Free. Synthflow starts at $29/mo. AssemblyAI is $29/mo cheaper on the entry tier than Synthflow.
See price history: AssemblyAI · Synthflow
How pricing works
These two tools don't price the same way, so the headline numbers below aren't directly comparable until you plug in your own volume.
- AssemblyAI (Per Usage) — AssemblyAI bills purely on usage. There is no fixed per-seat fee, so the monthly cost depends entirely on how much you consume.
- Synthflow (Hybrid) — Synthflow is hybrid: a fixed subscription from $29/mo plus metered usage on top (Starter). Your real bill moves with volume, not seat count.
Per-minute, per-credit and per-token rates exclude any downstream model, speech or telephony costs unless the vendor states otherwise.
Speech AI platform for developers — long-form audio transcription, speaker diarization, and Universal-2 speech understanding models. Usage-based pricing: Best model at $0.37/hr audio, Nano tier at $0.12/hr. Pay-as-you-go with $50 free credit. Popular with podcast platforms, meeting recorders, and companies building on top of long-form audio.
No-code AI voice agent builder with tiered subscriptions + per-minute overages. Starter $29 (50 min), Pro $99 (200 min), Growth $449 (1000 min), Agency $899 (2000 min), Enterprise custom (10K+ min). White-label option runs ~$2,000/mo. Voice engine alone ~$0.09/min; all-in $0.15–0.37/min with LLM + telephony.
All plans compared
| Tier role | Plan | AssemblyAI monthly | AssemblyAI annual | Synthflow monthly | Synthflow annual |
|---|---|---|---|---|---|
| Free / starter | Pay-as-you-go: Universal-2 (async) / — | Free | Free | — | — |
| Entry paid | — / Starter | — | — | $29 | $29 |
| Mid tier 1 | — / Pro | — | — | $99 | $99 |
| Mid tier 2 | — / Growth | — | — | $449 | $449 |
| Pro / power | — / Agency | — | — | $899 | $899 |
| Enterprise | Enterprise | Custom | Custom | Custom | Custom |
Tier names differ across vendors. Rows are aligned by tier role, not name. Full tier structures on each tool's page.
What each is best for
AssemblyAI is worth it if… developers processing long-form audio at scale — podcasts, recorded meetings, call recordings. The per-hour pricing works out cheaper than Deepgram for batch transcription (as opposed to real-time streaming).
Synthflow is worth it if… small businesses and agencies that want no-code AI voice agents without touching a developer platform like Vapi or Retell. Starter ($29) makes prototyping cheap.
Bottom line: Choose based on how you want to pay — AssemblyAI is per usage, Synthflow is hybrid.
Choose AssemblyAI over Synthflow if…
Choose AssemblyAI if…
- You want to pay only for actual usage (per usage, a free entry tier).
- You match the profile AssemblyAI is built for: developers processing long-form audio at scale — podcasts, recorded meetings, call recordings.
- You need a general-purpose voice agents & speech/audio option rather than a vertical-specific one.
Choose Synthflow if…
- You're fine with a base subscription plus metered usage on top (from $29/mo).
- You match the profile Synthflow is built for: small businesses and agencies that want no-code AI voice agents without touching a developer platform like Vapi or Retell.
- You need a general-purpose voice agents & speech/audio option rather than a vertical-specific one.
At a glance
| AssemblyAI | Synthflow | |
|---|---|---|
| Free plan | Yes | No |
| Entry price | Free | $29/mo |
| Enterprise available | Yes | Yes |
| Pricing model | Per Usage | Hybrid |
| Last verified | September 20, 2026 | September 10, 2026 |
| Full pricing | View full pricing | View full pricing |
Pricing last verified September 20, 2026. Tracked daily.