Speechmatics vs Soniox: Which Speech-to-Text API Delivers?

Soniox publishes its own benchmark results showing strong WER numbers. Speechmatics points to G2-verified scores from enterprise reviewers: 94% for environmental noise adaptation, 93% for low-latency processing, and 88% for speaker differentiation. In real-world deployments with diverse accents, background noise, and multi-speaker scenarios, independent validation is more reliable than self-reported benchmarks.

Speechmatics supports 55+ production-proven languages with the Ursa 2 model covering all accents and dialects. Soniox supports 60+ languages with a single multilingual model. Both offer broad language coverage, but Speechmatics' language support is production-proven across enterprise deployments with G2-verified scores for multilingual recognition.

Yes. Speechmatics offers real-time speaker diarisation at no extra charge — a key differentiator for voice agents, call centres, and meeting transcription. Soniox also offers speaker diarisation, but Speechmatics' implementation is proven at enterprise scale with G2 reviewers scoring it 88% for speaker differentiation across verified reviews.

Yes. Speechmatics offers cloud, on-premises, on-device, and fully air-gapped deployment options. This is essential for defence, healthcare, and environments without internet connectivity. Soniox offers cloud API and sovereign cloud but does not support on-device or air-gapped deployment.

Soniox bills by token, which it publishes as about $0.10/hr for async and $0.12/hr for real-time transcription; translation and custom context are billed as extra tokens. Speechmatics uses per-hour pricing from $0.12/hr for Melia batch transcription, with speaker diarisation and custom dictionary included. Soniox no longer offers free API credits, while new Speechmatics accounts get $100 in credit to get started.

Yes. Speechmatics is a pioneer in speech recognition with over a decade of R&D, holding ISO 27001, SOC2 Type II, HIPAA, and GDPR compliance. Every enterprise customer gets a dedicated CSM, SE, and direct engineering access — all included at no extra charge. Speechmatics has a proven track record under high-concurrency production load with formal SLAs, serving customers across healthcare, finance, media, and government. We also offer a purpose-built medical model trained on FDA/MHRA drug names and SNOMED CT terminology. Soniox reserves dedicated support and SLAs for its Business and Enterprise plans.

Yes. Speechmatics offers a straightforward REST API and WebSocket interface for real-time transcription. New accounts get $100 in credit to get started, plus hands-on migration support from our customer success team. G2 reviewers rate Speechmatics 97% for installation and setup ease.

Melia is Speechmatics’ new multilingual speech-to-text model with native code-switching across all 55+ supported languages in a single pass — no per-language model selection needed. It outperforms Deepgram, Microsoft, and AssemblyAI on most FLEURS language benchmarks, making it a strong fit for multilingual content, accented speakers, and global deployments. Priced from $0.12/hr for batch, with $100 in credit to get started, it’s also the most affordable model in the Speechmatics range.

Not for its API. Soniox stopped offering free API credits to new sign-ups in October 2025, so API usage is pay-as-you-go; its consumer Soniox App has a free plan with weekly credits. New Speechmatics accounts get $100 in credit to get started, with no card required.

No. Soniox’s speech models are proprietary and API-only; only its SDKs and the Soniox Compare tool are open source (MIT). If you need to run speech-to-text inside your own infrastructure, Speechmatics offers on-premises, on-device and fully air-gapped deployment.

Yes. Speechmatics translates speech in real-time and batch between English and 34 languages, with up to 5 target languages per request. It also runs on-premises, which Soniox doesn’t offer.