--- title: "Cartesia free inference" description: "A recurring no-cost API allowance covering 3 cataloged models." canonical_url: "https://freeinferencing.com/provider/cartesia/" md_url: "https://freeinferencing.com/provider/cartesia.md" last_updated: "2026-09-19" --- # Cartesia > A recurring no-cost API allowance covering 3 cataloged models. ## Classification - **Directory:** Current - **Free access:** Always-free quota - **Status:** Available now - **Confidence:** High - **Payment card:** No - **Account:** Required - **Equivalent paid value:** Up to $1.00/mo - **API endpoint:** `https://api.cartesia.ai` ## Models mentioned - `sonic-3.6` - `ink-2` - `sonic-3.6-2026-08-27` ## Limits and terms ```yaml plan_price_usd_per_month: 0 credits_per_month: 20000 approximate_tts_minutes_per_month: 27 approximate_stt_hours_per_month: 1.85 tts_concurrent_requests: 2 stt_concurrent_requests: 8 ``` ## What happens to your prompts? **Not private.** Default terms permit indefinite storage and perpetual use of inputs and outputs for labeling, improvement, promotion, and model training. Privacy is audited separately from price. Review the current governing terms before sending sensitive or regulated data. ## Data governance and agreements ```yaml data_governance: review_status: reviewed plan_scope: Cartesia API and web services. Default consumer/developer terms differ from enterprise TTS and STT zero-data-retention arrangements. prompt_retention: Inputs and outputs may be hosted, cached, stored, reproduced, and used while stored to operate, improve, and promote the service. No default fixed retention period is published. response_retention: Outputs are covered by the same storage and use license. Enterprise ZDR can prevent retention for eligible TTS and STT payloads. ordinary_logging: Account, device, service activity, content, and safety or troubleshooting information is collected under the privacy policy. model_training: Unless otherwise agreed, Cartesia may use inputs, outputs, and interactions for labeling, classification, moderation, and model training under a perpetual license. product_improvement: Default terms expressly authorize service and model improvement and enhancement with Content. human_or_operator_access: Cartesia reserves the right to review or monitor inputs and outputs using automated and manual tools. subprocessors_and_routing: Contracted service providers can receive content rights needed to operate the service; third-party services and enterprise subprocessors may separately process data. deletion_controls: Users can opt out of future training use, but the opt-out does not reverse prior uses or model improvements. Enterprise ZDR is available for eligible TTS and STT APIs. caveat: Free-tier content is training-eligible by default. The opt-out is prospective, and enterprise ZDR is neither available by default nor applicable to every product. agreements: terms_of_service: https://www.cartesia.ai/legal/terms privacy_policy: https://www.cartesia.ai/legal/privacy acceptable_use_policy: https://www.cartesia.ai/legal/acceptable-use ``` ## Eligibility ```yaml account_required: true payment_method_required: not_explicitly_documented commercial_use_on_free_plan: false ``` ## API compatibility and modalities - **Compatibility:** Cartesia Rest And Websocket - **Modalities:** Text To Speech, Speech To Text, Speech / audio ## Before you build with Cartesia ### Read the classification narrowly This record describes the bounded offer supported by evidence on 2026-09-19; it does not guarantee permanence, production suitability, uptime, latency, model quality, or access from every account and region. “Always-free quota” should be interpreted together with the Current directory placement, High confidence, No payment-card status, and the plan-specific sources below. ### Resolve the live model route The snapshot records 3 model IDs. Match the exact ID against the provider's current catalog before using it in code because zero-price routes, aliases, context limits, and feature support can rotate while an older documentation page remains online. ### Match the quota to the workload shape Translate the allowance into peak requests per minute, input and output tokens, concurrency, retries, and every daily or monthly ceiling that applies to the intended account. The first limit reached by the workload is the practical ceiling. A large token pool can still fail interactive bursts, and a high request limit can still fail long-context work. Include tool calls and retry traffic, test the largest realistic payload, and treat research, experimental, and community access as conditional on their eligibility and fair-use terms. ### Preserve billing and privacy boundaries The recorded payment-card requirement is No, and account access is required. Confirm both in the live signup flow, set provider-side budgets when charges are possible, and observe the balance or usage fields after a complete request. The prompt-handling classification is **Not private** because Default terms permit indefinite storage and perpetual use of inputs and outputs for labeling, improvement, promotion, and model training. Re-read the terms for the exact route and plan before sending sensitive, regulated, or proprietary content. ### Follow the evidence, then re-check it This record links 9 first-party sources covering the offer, catalog, limits, pricing, terms, privacy, or adoption evidence available to the audit. Prefer the newest and most specific governing document or live catalog when sources disagree. A dated finding can become stale even when the page remains online, so retain the source and snapshot that supported the decision and submit a correction when a provider changes a material term. ### Plan fallback without policy drift A fallback should preserve modality, context length, streaming, structured output, tools, safety controls, and data terms, not only API syntax. Decide which errors may retry, cap retry storms, and prevent an exhausted free route from silently switching to a billable model. Rotating aliases and free pools can change behavior without changing the endpoint, so retain the response model field and test at least one substitute route before the primary offer becomes unavailable. ### Monitor the offer as a dependency Capture the model ID, response model, rate-limit headers, usage fields, latency, HTTP status, and provider request identifier. Watch authorization failure, quota exhaustion, catalog removal, policy revision, and balance movement as separate failure modes. Re-check the live catalog and governing sources on a schedule proportionate to the workload's importance, and keep an owner and exit path for any production dependency on volatile free capacity. ### Test one complete request before scaling Start with the smallest permitted request using the exact credential, model ID, endpoint, region, and account type intended for deployment. Record the status, headers, usage fields, response model, latency, and dashboard balance movement. Then exercise an invalid model, quota exhaustion, or rate limit so failure is explicit and cannot silently switch to a paid route. Validate streaming, structured output, and tool calls separately because a free model can expose fewer features than its paid counterpart. Keep a budget ceiling outside the application whenever billing is possible, and do not send sensitive data until the observed route matches the reviewed agreement. ## Primary sources - [Pricing](https://www.cartesia.ai/pricing): Official Pricing - [API documentation](https://docs.cartesia.ai/): Official Docs - [Cartesia Terms of Service](https://www.cartesia.ai/legal/terms): Official Terms - [Cartesia Privacy Policy](https://www.cartesia.ai/legal/privacy): Official Privacy - [Cartesia Acceptable Use Policy](https://www.cartesia.ai/legal/acceptable-use): Official Aup - [Cartesia Zero Data Retention](https://docs.cartesia.ai/enterprise/zero-data-retention): Official Docs - [PyPI download stats for the official cartesia package](https://pypistats.org/api/packages/cartesia/recent): Package Registry Stats - [npm download stats for the official @cartesia/cartesia-js client](https://www.npmjs.com/package/@cartesia/cartesia-js): Package Registry Stats - [Cartesia first-party Sonic and Ink model families](https://www.cartesia.ai/launch): Official Product ## Sitemap See the full [semantic sitemap](/sitemap.md) for every page and markdown mirror.