Cartesia vs Fonio AI — Pricing, Plans, and Verified Costs (2026)
Cartesia starts at $5/mo. Fonio AI starts at $106/mo. Cartesia is $101/mo cheaper on the entry tier than Fonio AI.
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.
- Cartesia (Hybrid) — Cartesia is hybrid: a fixed subscription from $5/mo plus metered usage on top. Your real bill moves with volume, not seat count.
- Fonio AI (Hybrid) — Fonio AI is hybrid: a fixed subscription from $106/mo plus metered usage on top (Solo). 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.
Voice AI research lab building state-of-the-art speech synthesis models (Sonic) with ultra-low latency (<100ms). Usage-based pricing: pay-per-character generation, entry rate around $0.017/1K characters. Enterprise custom for volume. Popular with voice agent developers who need faster-than-ElevenLabs synthesis for real-time conversations.
German AI phone agent platform priced in EUR. Solo €99 (1,000 min, 1 phone number), Team €299 (3,000 min, 5 concurrent calls), Business custom (100+ calls/day). Prepaid alternative from €0.20/min with €300 minimum top-up. Solo includes €0.15/additional minute. 20+ voices, 25+ languages, unlimited AI assistants across all tiers.
All plans compared
| Tier role | Plan | Cartesia monthly | Cartesia annual | Fonio AI monthly | Fonio AI annual |
|---|---|---|---|---|---|
| Free / starter | Free / Business | Free | Free | Free | Free |
| Entry paid | Pro / Solo | $5 | $4 | $106 | $106 |
| Mid tier | Startup / — | $49 | $39 | — | — |
| Pro / power | Scale / — | $239 | $239 | — | — |
| Teams | — / Team | — | — | $320 | $320 |
| Enterprise | Enterprise / — | 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
Cartesia is worth it if… developers building real-time voice agents where sub-100ms TTS latency matters (voice interruption handling, conversational feel). Sonic model is competitive with ElevenLabs on quality and faster on latency.
Fonio AI is worth it if… European SMBs and mid-market teams that want a German-founded, GDPR-native AI phone agent without navigating US-first platforms like Vapi or Retell. Solo (€99) fits 1–20 calls/day; Team (€299) opens 5 concurrent lines.
Bottom line: Similar positioning, closer to a preference call than a strategic one.
Choose Cartesia over Fonio AI if…
Choose Cartesia if…
- You're fine with a base subscription plus metered usage on top (from $5/mo).
- You match the profile Cartesia is built for: developers building real-time voice agents where sub-100ms TTS latency matters (voice interruption handling, conversational feel).
- You need a general-purpose voice agents & speech/audio option rather than a vertical-specific one.
Choose Fonio AI if…
- You're fine with a base subscription plus metered usage on top (from $106/mo).
- You match the profile Fonio AI is built for: European SMBs and mid-market teams that want a German-founded, GDPR-native AI phone agent without navigating US-first platforms like Vapi or Retell.
- You need a general-purpose voice agents & speech/audio option rather than a vertical-specific one.
At a glance
| Cartesia | Fonio AI | |
|---|---|---|
| Free plan | Yes | No |
| Entry price | $5/mo | $106/mo |
| Enterprise available | Yes | No |
| Pricing model | Hybrid | 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.