Ultra-low-latency text-to-speech

Scores as of 2026-09-14 (43 days old; Depot marks scores stale after 30 days). The pick is still Depot's current editorial pick; it has not been re-reviewed since. Prices below carry their own dates.

Depot Pick

Cartesia · 7.85/10 for this job (curated estimate, high confidence)

Latency capability + pricePerf.

Runner-up

ElevenLabs · 8.40/10

Scores higher than the pick on: Capability fit, Latency / reliability, Developer & agent DX, Maturity / track record.

When not to use the pick

Need largest voice library — ElevenLabs; already standardized on Deepgram Voice Agent; need expressive/empathic TTS — Hume. PlayHT/PlayAI is sunset (Meta) — do not pick.

Lock-in / migration

The pick has lower stored lock-in risk than runner-up ElevenLabs (4.5 vs 5.5). Self-host fallback listed for this job: Kokoro-82M, Piper.

Sourced price (usd_per_1k_characters)

Pick: no sourced price in this job's unit (no_sourced_price).

Cheapest matching SKU: Deepgram Aura-2 $0.03 — source, as of 2026-10-03, re-checked 2026-10-27. Not the pick; not quality-adjusted.

Price history: first seen 2026-10-03 · last changed no change recorded · history JSON

Free option

• Gemini 3.8 Flash TTS free tier (free tier unspecified) — source, as of 2026-10-26
• Groq Free Plan Orpheus TTS (free) — source, as of 2026-10-24
• Kokoro-82M (oss) — source, as of 2026-10-25

Failure modes to watch

• Runaway spend: Set a budget and a tool-call cap per task. Alert when spend jumps. Stop the run at the cap instead of summarizing a partial trace as success.
• Confirmation skip: Gate those tool names on an approval id recorded before the call. A missing approval is a failure even if the downstream tool returns success.
• Identity confusion: Bind every tool call to a user or tenant id. Refuse the call if that id changed mid-task. For a public bot, the operator owns the words the bot shows.
• Non-determinism: Run the task more than once and compare the end state, not a single transcript. Record the trial count next to any success rate you cite.
• Over-refusal: Log refusals separately from successes. Review a sample against the written policy. Do not treat a refusal as a pass, and do not weaken a safety check to raise the pass rate.
• Partial tool success: Require a per-item status and a failure count. Success for the task requires the failed count to be zero or explicitly handed to a retry queue.

Reported outcomes (submitted reports only)

This job: loading… JSON · reports never change scores · seed/test records excluded

Depot Pick (Cartesia) on this job: loading… JSON · reports never change scores · seed/test records excluded

Cite: Agent Provider Depot, Depot Pick for realtime-tts: cartesia, scores as of 2026-09-14. Agents: GET /api/decide?jtbd=realtime-tts