Cartesia vs Resemble AI: pricing, features and which to choose

Cartesia is a San Francisco startup founded in 2023 by Karan Goel, Albert Gu, Arjun Desai, Brandon Yang and Chris Ré, researchers from Stanford's AI lab. Gu co-created the S4 and Mamba state space model architectures, which process long sequences with less memory than transformers, and that research is the basis of the company's products. Cartesia launched its Sonic text-to-speech model in 2024 and raised a $64 million Series A led by Kleiner Perkins in March 2025, bringing total funding to $91 million, according to Fortune. Its homepage names ServiceNow, Retell, Blue Machines and Quora among customers. The company's pitch is speed: models that start speaking quickly enough for live phone conversation, sold through one API that covers speech generation, transcription and complete voice agents.

Developers reach Cartesia through a REST and WebSocket API or the browser playground. Sonic turns text into streaming audio, with controls for speed, emotion and pronunciation, and supports more than 40 languages. Instant voice cloning creates a voice from a few seconds of audio on paid plans, and professional cloning trains a closer copy from longer recordings on the Startup plan and above. A localisation feature gives a cloned voice a new accent. Ink transcribes live audio for agents that need to hear callers. Managed Agents, the newest product, hosts complete phone agents with telephony, so a team can define an agent's prompt and tools without wiring a separate orchestration layer. Cartesia also offers on-premises and on-device deployment for customers with data residency rules.

Cartesia's voice library and creator tools are thinner than ElevenLabs, which also offers dubbing, sound effects and music, so it is a weaker fit for video producers and audiobook narrators. Managed Agents are newer than Vapi or Retell and have fewer integrations. Credit-based billing means long-form narration gets expensive faster on the low tiers. ElevenLabs Flash competes directly on latency with a larger voice catalog. Deepgram's Aura voices are cheaper per minute but less expressive, and Hume, once a rival on expressive speech, is closing its TTS API in November 2026. Pick Cartesia when you are building a real-time voice agent or interactive app and the delay before the first syllable is the metric you care about, or when you need on-device or on-premises speech models.

Resemble AI is a Toronto and San Francisco company founded in 2019 by Zohaib Ahmed and Saqib Muhammad to make synthetic voices for game studios. For five years it sold voice cloning, text-to-speech and speech-to-speech through a web studio and API, raising an $8 million round in July 2023 and later a $13 million round aimed at AI-generated threats. In August 2026 Ahmed published a post titled "Why a former voice AI company went all in on deepfake detection" confirming the company had stopped selling voice generation to new customers. Existing voice customers are still supported. Resemble also retired more than 300 older blog posts on voice cloning, which is why many old links now land on that announcement. Anyone researching Resemble as a voice generator should treat it as a detection vendor with a voice research arm.

The current product is a set of five APIs. Detect returns a verdict on whether audio, video or an image is synthetic in under 300 milliseconds, according to the company. Watermarker embeds an inaudible or invisible mark at the point of generation and reads it back after compression and re-encoding, with C2PA support. Identity enrolls a known voice and face, then checks whether an incoming call or video matches it. Signal matches calls against libraries of known fraud patterns without storing transcripts, and Intelligence turns a detection score into plain-language reasoning and JSON. Ready-made products sit on top: meeting protection for Microsoft Teams, a Chrome extension that flags deepfakes in the browser, and agent detection for spotting AI callers. A typical deployment pipes contact-center audio or uploaded media through Detect and routes flagged items to an analyst.

The main limitation for most readers is that Resemble no longer sells the product it was known for. Teams that want hosted voice cloning should look at ElevenLabs, which offers instant and professional cloning from $5 a month, or Respeecher for studio-grade speech-to-speech. Developers comfortable running models themselves can use Chatterbox from Resemble's own repository at no cost, but without a commercial voice service behind it. On detection, Resemble competes with Reality Defender and Pindrop, which also sell real-time deepfake screening to banks and call centers; Resemble's edge is that it publishes self-serve prices and an API key you can get without a sales call. Pick Resemble if you need to screen calls, meetings or uploads for synthetic media. Look elsewhere if you need to generate voices.