# AssemblyAI vs Soniox

AssemblyAI records 453,591 monthly visits with -6.9% month-over-month growth and Freemium, Contact for Pricing pricing. Soniox records 335,647 monthly visits with +2.2% growth and Paid pricing.

| Metric | [AssemblyAI](https://openaitools.app/tool/assemblyai) | [Soniox](https://openaitools.app/tool/soniox) |
| :--- | :--- | :--- |
| Website URL | https://www.assemblyai.com | https://soniox.com |
| Categories | AI Speech-to-Text, AI Transcription, AI Speech Recognition, AI Developer Tools | AI Speech-to-Text, AI Text-to-Speech, AI Translate, AI Speech Synthesis |
| Pricing Model | Freemium, Contact for Pricing | Paid |
| Monthly Visits | 453,591 | 335,647 |
| MoM Growth Rate | -6.9% | +2.2% |
| Primary Market | Brazil | United States |
| Direct Visits | 281,472 | 181,748 |
| Review Score | 4.6 | 4.5 |
| Saved Count | 9 | 0 |
| Supported Platforms | Website | Website |

## AssemblyAI

AssemblyAI builds speech AI models and the infrastructure to run them, aimed at developers and product teams adding voice to an application. Its core offering is speech-to-text: an asynchronous API for pre-recorded audio, a realtime API for streaming and voice agents, and a synchronous API for short clips and dictation. The company's flagship accuracy model is marketed as top of independent benchmarks, with strong speaker diarization and native code-switching across dozens of languages.

On top of transcription, AssemblyAI offers a Speech Understanding API that layers tasks such as summarization, sentiment, topic detection, PII redaction, content moderation and guardrails onto transcripts. It has also released its first text-to-speech model, AssemblyAI-TTS-1, built for voice agents on live calls, plus an LLM Gateway for routing model calls and a Dictation API. Models can run on AssemblyAI's managed inference cloud, or self-hosted in a customer's own VPC or on-premises environment.

Pricing is pay-as-you-go after a free trial: for example, pre-recorded transcription is billed per audio hour, with optional add-ons such as speaker diarization, keyterms prompting and medical or veterinary modes priced separately. Enterprise plans offer custom rate limits, higher concurrency and compliance features including SOC 2 Type 2, HIPAA and GDPR.

**Pricing & Plans:** Free trial to start, then pay-as-you-go per audio hour and per add-on feature — for example around $0.15/hr for the Universal-2 model and around $0.21/hr for the more accurate Universal-3.5 Pro model, with extras like diarization billed individually. Enterprise and custom-rate-limit plans are available via sales.

- **Async, realtime and sync speech-to-text:** Choose pre-recorded transcription for files, a realtime API for live streams and voice agents, or a synchronous endpoint for short clips and dictation.
- **Audio intelligence and Speech Understanding:** Layer summarization, sentiment, topic detection, PII redaction, content moderation and guardrails onto transcripts without building your own models.
- **Text-to-speech for voice agents:** AssemblyAI-TTS-1 is trained on real phone calls for natural, low-latency speech, targeted at IVR and voice-agent use cases.
- **High accuracy with diarization:** Flagship models emphasise exact transcription, speaker labels and native code-switching across many languages, supported by published benchmarks.
- **Flexible deployment:** Run models on AssemblyAI's managed cloud with unlimited concurrency, or self-host in your own VPC or on-prem for full data control.

**Strengths:** One API family covering transcription, understanding and text-to-speech; Transparent per-hour pay-as-you-go pricing with a free trial; Self-hosting option for teams with strict data-residency requirements; Strong accuracy and diarization performance backed by published benchmarks

**Limitations:** Costs scale with volume and add-ons can raise the effective per-hour rate; Some advanced features are model-specific and not available on every model; Heavier product surface than a simple transcription API may be overkill for basic needs

[Profile (Markdown)](https://openaitools.app/tool/assemblyai.md)

## Soniox

Soniox is a multilingual speech AI platform built for developers who need to power voice products. Rather than stitching together separate vendors for recognition, synthesis, and translation, it offers one unified API covering real-time speech-to-text, text-to-speech, and speech translation across 60+ languages and roughly 3,600 language pairs. The emphasis throughout is on doing the hard parts of voice AI well: high accuracy beyond English, seamless mid-sentence language switching, reliable handling of numbers and names, and low enough latency for live conversation.

On the recognition side, its STT models are marketed as highly accurate across accents, alphanumerics, domain vocabulary, and noisy, multi-speaker settings, with a newer model that recognises and filters out a voice agent's own speech. The text-to-speech line adds expressive control through audio tags, 200+ built-in voices tagged by gender, age, accent, and style, plus instant voice cloning from just a few seconds of audio. Translation handles code-switching environments where speakers change languages mid-sentence, and regional deployment lets teams run everything in-region for latency, data residency, and regulatory reasons, with audio processed in real time and never stored.

Soniox positions itself as enterprise-ready. Its site lists integrations with Perplexity, Genspark, Tana, and other platforms, and it publishes live side-by-side comparisons against providers like OpenAI, Google, Azure, Deepgram, Speechmatics, and AssemblyAI so developers can test on their own data. It is a paid API platform rather than a consumer app, aimed at teams building voice agents, wearables, dictation, and multilingual experiences at scale.

**Pricing & Plans:** Soniox is a paid API platform. Pricing is usage-based rather than a fixed consumer subscription, with plans and rates listed on its pricing page. There is no free consumer tier, so budget depends on your speech-processing volume and model choice.

- **Real-time speech-to-text:** Soniox STT delivers high accuracy across 60+ languages, accents, numbers, names, and domain vocabulary, engineered for fast multi-speaker conversations and noisy environments.
- **Text-to-speech and voice cloning:** Generate expressive speech in 60+ languages with audio tags, alphanumeric accuracy, seamless language switching, 200+ built-in voices, and instant voice cloning.
- **Real-time speech translation:** Translate speech in real time across roughly 3,600 language pairs, with low-latency output that starts before a sentence finishes and handles mid-sentence language switching.
- **Low-latency streaming:** Streaming models transcribe speech and start generating audio from the first few words, keeping interaction fast enough for live voice agents and captions.
- **Data residency and privacy:** Run STT and TTS in-region to meet latency, data residency, and regulatory needs, with audio processed in real time and never stored.

**Strengths:** One unified API for STT, TTS, and speech translation; Strong multilingual accuracy, including code-switching and alphanumerics; Low-latency streaming suited to live conversation and captions; Voice cloning and 200+ built-in voices for natural TTS

**Limitations:** Priced as an API platform, so cost scales with usage and needs developer integration; No consumer-facing free editing suite; it targets builders rather than end users; Advanced features like regional deployment may be limited during early access

[Profile (Markdown)](https://openaitools.app/tool/soniox.md)

## Frequently Asked Questions

### How do AssemblyAI and Soniox compare in monthly traffic?

AssemblyAI has 453,591 monthly visits, while Soniox has 335,647. Traffic estimates describe audience size, not product quality.

### How do their growth rates compare?

AssemblyAI has a month-over-month growth rate of -6.9%; Soniox has +2.2%.

### How does pricing compare?

AssemblyAI: Freemium, Contact for Pricing. Free trial to start, then pay-as-you-go per audio hour and per add-on feature — for example around $0.15/hr for the Universal-2 model and around $0.21/hr for the more accurate Universal-3.5 Pro model, with extras like diarization billed individually. Enterprise and custom-rate-limit plans are available via sales. Soniox: Paid. Soniox is a paid API platform. Pricing is usage-based rather than a fixed consumer subscription, with plans and rates listed on its pricing page. There is no free consumer tier, so budget depends on your speech-processing volume and model choice.

## Alternatives

| # | Tool Name | Monthly Visits | MoM Growth Rate | Pricing Model | Summary | Profile (Markdown) |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| 1 | [OpenAI Platform](https://openaitools.app/tool/openai) | 234,678,639 | -9.6% | Paid | Enterprise developer platform and API for deploying GPT-6 Astra, Sol, Luna, and realtime multimodal agents. | [.md](https://openaitools.app/tool/openai.md) |
| 2 | [ElevenLabs](https://openaitools.app/tool/elevenlabs-io) | 42,396,771 | +26.1% | Freemium, Paid, Contact for Pricing | Industry leader for high-fidelity speech synthesis and voice cloning, though less focused on raw streaming STT infrastructure. | [.md](https://openaitools.app/tool/elevenlabs-io.md) |
| 3 | [Fish Audio](https://openaitools.app/tool/fish-speech) | 8,557,159 | +1.6% | Freemium | Open-source voice platform offering studio-grade text-to-speech and instant cloning, suitable for self-hosting deployments. | [.md](https://openaitools.app/tool/fish-speech.md) |
| 4 | [MiniMax Audio](https://openaitools.app/tool/minimax-audio) | 5,253,734 | -13.2% | Contact for Pricing | Provides expressive multilingual text-to-speech and voice cloning APIs with strong performance across global languages. | [.md](https://openaitools.app/tool/minimax-audio.md) |
| 5 | [Cartesia](https://openaitools.app/tool/cartesia-ai) | 1,782,707 | +49.7% | Contact for Pricing | Delivers extremely low-latency real-time text-to-speech and streaming transcription APIs tailored for conversational agents. | [.md](https://openaitools.app/tool/cartesia-ai.md) |
| 6 | [Deepgram Voice AI](https://openaitools.app/tool/deepgram-voice-ai) | 863,852 | +31.8% | Free Trial | Provides ultra-fast real-time speech-to-text and voice AI APIs, but with less emphasis on integrated translation. | [.md](https://openaitools.app/tool/deepgram-voice-ai.md) |
| 7 | [Vapi](https://openaitools.app/tool/vapi) | 662,301 | -11.4% | Freemium | Specialises in orchestrating conversational voice agents and telephony integrations rather than standalone speech APIs. | [.md](https://openaitools.app/tool/vapi.md) |
| 8 | [Noiz AI](https://openaitools.app/tool/noiz-ai) | 441,445 | -30.1% | Paid | Specialises in emotional text-to-speech generation and multilingual video dubbing, but less robust for raw transcription pipelines. | [.md](https://openaitools.app/tool/noiz-ai.md) |
| 9 | [Gladia](https://openaitools.app/tool/gladia) | 232,451 | +6.4% | Freemium, Contact for Pricing | Focuses on robust real-time audio transcription and advanced audio intelligence features via developer APIs. | [.md](https://openaitools.app/tool/gladia.md) |
| 10 | [Gradium](https://openaitools.app/tool/gradium) | 126,416 | +128.7% | Freemium, Contact for Pricing | Offers real-time speech-to-text, TTS, and live translation APIs with competitive latency for voice applications. | [.md](https://openaitools.app/tool/gradium.md) |

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Source: https://openaitools.app/compare/assemblyai-vs-soniox

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