> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cartesia.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Changelog 2025

> Product, API, and platform changes for 2025

<Update label="December 2025">
  ### API

  * **sonic-3-latest** (preview) and dated **sonic-3-YYYY-MM-DD** snapshots.
  * **sonic-3-latest** added to Playground TTS with banner when selected. See [Changelog 2026](/changelog/2026).

  ### Voice changes

  * **Voice Library** — December: 25 new voices across 6 languages (12 English, 6 Hindi, 4 Arabic, 1 Spanish, 1 Japanese); 14 featured.
  * Voice library changes; featured voice badge on voice page; **`/voices/recent`** endpoint.

  ### Playground

  * **Report generation** (report button, alert when user reports).
  * **Voice move**; **archive and publish** voices.
  * **PVC**: custom PVC voices UI, multiple user errors surfaced to UI, feature flag for custom model during creation.
  * **Pronunciation dicts**: new backend APIs, generator on create/edit, case sensitivity badge.
  * **Agents**: new text-to-agent UI, create agent from **Github repo tarball**, system prompt generator for UI agent.
  * **Narrations sunset** notice; TTS History pagination; auth strategy for access-tokens.
  * **sonic-3-latest** banner and naming.

  ### Other

  * PVC, STT, and agent improvements.
  * Error handling and error codes.
</Update>

<Update label="November 2025">
  ### API

  * Improved error handling and public error responses; cache invalidation by voice ID.
  * IPVC train API (remove **`markAsReady`**); dataset files overfetch fix; default voice logic fix.

  ### Playground

  * Pronunciation dicts migrate to new backend APIs; persist visual theme to DB; PVC pipeline error and recommendations.
  * Call logs conversation view default; TTS textarea height fix; Sonic-3 model for partners shown.
  * Billing overage "blood bar" and alert fixes; PVC gate for Startup plan.
  * Pronunciation dict generator on create/edit; API version in dialog; featured voice toggle; narrations model selection.

  ### Line / Agents

  * No user audio warning (250ms); Pipecat DeepgramNovaVADFilter.
  * Call recording and artifact storage fixes.

  ### Models / Voices

  * Sonic 3 PVC and normalizer updates; LoRA and PVC error handling; expand option for dataset file count.
  * **`preview_file_url`**; **`tags_operator`** on GET /voices; restrict delete to non-public voices; **`owner_id`** check for fine tune voices; **`user_errors`** for PVCs.
  * New Arabic accents; African French and Canadian French.
</Update>

<Update label="October 2025">
  ### Model changes

  * **Sonic 3 launch (Oct 27)** — **sonic-3-2025-10-27** stable snapshot released; 42 languages; volume, speed, and emotion controls.
  * Real-time conversation with emotion and laughter; \~190ms median latency. See [Sonic 3](/build-with-cartesia/tts-models/latest) and [Volume, Speed, and Emotion](/build-with-cartesia/sonic-3/volume-speed-emotion).

  ### Other

  * Continued PVC, STT, and agent improvements; error handling and public errors; manifone voices; Sonic 3 PVC and normalizer updates.
  * Transcript buffer multilingual and Thai pronunciation dictionary fix; TTFA buffering and reporting; Voice Conversion operator reload; audio norm operator.
</Update>

<Update label="September 2025">
  ### API

  * **`user_id`** to **`owner_id`** in API (model aliasing / ownership).
  * Improved error handling and version/limit checks.

  ### Line / Agents

  * Warning if no user audio for 250ms+; Pipecat **DeepgramNovaVADFilter** for spurious `on_speech_started`.
  * Call recording and artifact storage fixes.

  ### Models / Voices

  * STT: Migrate STT providers to Deepgram where appropriate; Deepgram for non-English or language-detect agents; word-level user text chunks.
  * Sonic 3 / PVC: Sonic 3 PVC updates; Hindi Sonic 3 normalizer revert; LoRA data processing and expand option for dataset file count; PVC errors to webhook.
  * Manifone new voice; African French and Canadian French accents; partner agents can configure TTS models.

  ### Other

  * LoRA bugfixes.
</Update>

<Update label="August 2025">
  ### API

  * Production-facing agent WebSocket; **cancel endpoint** for ending live calls.
  * Improved error handling and public error codes; cache invalidation by voice ID.

  ### Playground

  * Telephony: stop billing for customer-managed numbers; Cartesia vs Twilio param separation.
  * Outbound number management columns.

  ### Line / Agents

  * **Deepgram Nova VAD** (`utterance_end_ms` configurable via **`vad_stop_secs`**).

  ### Models / Voices

  * New endpoint for **`<audio>`** tags; **accent** column on voice API; **`max_buffer_delay`** applied to continuations; eu-north-1 region.
  * **GET /voices** **`tags_operator`**; **`preview_file_url`**; restrict deleting voices to non-public; check **`owner_id`** when listing fine tune voices; **`user_errors`** for PVCs from API.
  * New Arabic accents migration.

  ### Other

  * Max rollover multiplier for credit plans.
</Update>

<Update label="July 2025">
  ### API

  * **`deploy_error`** status fix.

  ### Playground

  * **LangChain** launched voice agents with Cartesia Sonic TTS.
  * Billing: Stripe customer for enterprise if needed; call runtime logs in call logs side panel; Call Logs UI nits (from June work).

  ### Line / Agents

  * Partner pipeline parity with User Agent; **concurrency fix** (negative concurrency); agent metric LLM credit usage for evals; AgentEvaluations functionality.
  * User Code Connector WS handlers fix; agent end turn handling; summarization system prompt; **`user_prompt`** in API; transcript removed from agent metric result; deadlock fix in WS timeout.

  ### Other

  * Flushing and concurrency fixes.
</Update>

<Update label="June 2025">
  ### API

  * **UserCodeAgent** deployment URL; **cancel endpoint** for force-ending live calls via API; Agent EoUD metric; cartesia agent speed-up; user prompt stored separately in agent metrics; **`agent_evaluations`** table; async flush for aggregator; User Code Connector WS and last bot turn handling; deployment URL delay on pickup.
  * Concurrency and WS timeout fixes; improved goroutine handling; agent workers **`/chats`** timeout increase.

  ### Playground

  * **Call Logs** page for agents with data table and side panel; **Agents demo** with Twilio web dialer, visualizer, and like/dislike feedback; deployment detail page and list; **Twilio number provisioning** (Parts 1 & 2); GitConnector redeploy on commit; deployment logs; zip upload for deployment; feature flag by organization; agents gated behind feature flag; **Deepgram as default STT** for agents; orgs v2 (frontend and backend); 20K credits for organizations; enterprise free trial days and email invoice options.
  * **Credit usage**: separate TTS & STT concurrency panels; STT and Infill charts; voice page copyable fields; call runtime logs in call logs panel.

  ### Models / Voices

  * STT: Whisper large v3; serve multiple models in STT pipeline; word-level user text chunks.
  * FinetunedSTTContext fixes.
</Update>

<Update label="May 2025">
  ### API

  * Voice conversion in enterprise.

  ### Playground

  * Post–April: Following [April 2025](/changelog/2025) API changes (embeddings removed; use [Voice IDs](/build-with-cartesia/tts-models/voice-ids) and [Clone Voice](/api-reference/voices/clone)).

  ### Line / Agents

  * User code deployments from DB; **`agent_deployments`** table; STT cartesia-streaming and Pipecat streaming Whisper; Bedrock proxy for OpenAI-compatible; timestamp bug fixes and default to original timestamps.
  * Partner `/chat` and `/config` updates; DTMF support in UserCodeConnector; endpointing architecture.

  ### Models / Voices

  * STT: Batch engine utilization; Pipecat streaming Whisper.
  * Deepgram STT client `url`/`base_url` fix.

  ### Other

  * Voice clone uploads fix.
</Update>

<Update label="April 2025">
  ### Breaking

  * **sonic-2-2025-04-16** — Starting with **`sonic-2-2025-04-16`**, we're removing support for: Embeddings; **`stability`** cloning mode; Experimental controls for speed and emotion. The **`similarity`** cloning mode is dramatically better. To control speed and emotion today, use Instant Voice Cloning (e.g. FFMPEG, Voice Changer, or instant clones from **`sonic-2-2025-03-07`** embeddings). Users who need embeddings or experimental controls can use API version **`2024-11-13`** with model **`sonic-2-2025-03-07`** (both still available). See [Older models](/build-with-cartesia/tts-models/older-models).

  ### API

  * listVoices by ID for single voice; warm-monkey PVC; **access tokens** (JWT); Cartesia-Version 2024-11-13; phoneme/original timestamps language check; TTS History source; LoRA from fine-tune checkpoints; context expiry replaced by input stream delay.
  * **`sonic-2`** and **`sonic-2-2025-04-16`** ignore experimental controls on TTS generations; voice cloning supports only **`similarity`** clones.
  * Removed embeddings from all endpoints; voices may only be specified by Voice ID; **`/tts`** cannot be called with voice embeddings.
  * Deprecated **`/voices/create`** and **`/voices/mix`**.
</Update>

<Update label="March 2025">
  ### Breaking

  * **sonic-2-2025-03-07** is the last Sonic 2 snapshot supporting voice embeddings and experimental controls. Use with API version **`2024-11-13`** for legacy behavior.
  * sonic-preview → JollyTotem, RoseLion deprecated; sonic-2 alias to jolly-totem for speaker switching. See [Older models](/build-with-cartesia/tts-models/older-models).

  ### API

  * **Cartesia-Version** updated to **2024-11-13**; model latency via header on bytes endpoint; new Sonic PVC model warm-monkey; listVoices by ID (single voice); **access tokens** (JWT signing, validation); API-level check for languages supporting phoneme and original timestamps.
  * Organizations and billing; **free credits** 10k → 20k; overages product; subscription cache invalidation webhook; TTS History **source** column (api, playground, narrations); LoRA voices from base VoiceVariation and checkpoint for fine tunes.

  ### Playground

  * **sonic-2** and **sonic-turbo** aliases launched; Sonic 2 / Sonic Turbo messaging (Turbo = 40ms latency).
  * cartesia.ai/sonic and playground updates.

  ### Line / Agents

  * Agent ID in websocket URL; telephony info on partner calls; Pipecat version upgrade; partner demo tool calls; warm-monkey PVC model; prespeak and function call flow updates.
  * Twilio voice routes support agent IDs; Keypad DTMF on agent; half-duplex STT and LLM context; original timestamps support in API.

  ### Other

  * **sonic-pvc** alias and DryVoice as sonic-pvc model. **Python SDK** announced.
</Update>

<Update label="February 2025">
  ### API

  * **listVoices** by ID; localize endpoint voice name fix; 400s for bad body params; text forcing max transcript length; **OpenAI-compatible STT server**; agent with local STT; voice tags; on-device transcripts in evals; jolly-totem as default sonic-preview.
  * S2S and Agents foundational blocks.

  ### Playground

  * Instant cloning enabled for free users; voice tags; localize refactored to use conditioning; listVoices can query by ID for single voice; Sarah (Similarity) and Southern Woman migrations; on-device transcripts.
  * Narrations settings (JSONB).

  ### Line / Agents

  * Agent with local STT; foundational S2S + Agents blocks; design and pipeline work.

  ### Models / Voices

  * STT: cartesia-streaming and Pipecat streaming Whisper; on-device transcripts.
</Update>

<Update label="January 2025">
  ### API

  * **sonic-lite** added to API; EU deployment for prod API; save option for TTS bytes handler; CORS header for **Cartesia-File-ID**; Stripe credits default to `char_limit` in checkout; Redis cache for overage settings; polar-mountain and VC in EU; ListFiles paginator fix.
  * Eval break/spell tags and replacement/normalization mode.

  ### Models / Voices

  * sonic-preview routed to MisunderstoodFrog; polar-mountain added and staged; visionary-yogurt timestamp requests for any language.
  * jolly-totem as default sonic-preview.
</Update>