How Accurate Is Speechmatics in 2026? Melia-1, Enhanced & Standard WER Benchmarks
Speechmatics offers three batch models: Melia-1 (mid-2026, $0.24/hr), Enhanced ($0.75/hr), and Standard ($0.45/hr). In VexaScribe's reading of the public benchmarks, Melia-1 achieved strong multilingual coverage, competing with AssemblyAI Universal-3.5 Pro (7.0%) at 20% lower cost. Enhanced separately delivered the strongest productized diarization result in the benchmark (8.6% DER on VoxConverse — better than the pyannote-standalone academic baseline). Standard is dominated by Melia-1 on every measured axis at nearly 2× the price.
WER (Word Error Rate) = (Substitutions + Deletions + Insertions) / total reference words — the NIST-standard ASR accuracy metric. Lower is better. All numbers below come either from Speechmatics' own published materials (labelled as vendor claims) or from published third-party benchmarks, cited to their sources. Full methodology and sources at the bottom of the page.
By VexaScribe Editorial · Published · Verified
VexaScribe does not sell a transcription API. This accuracy assessment has no commercial bias toward Speechmatics. Vendor accuracy claims are cited to the vendor's own published material throughout this page.
Speechmatics Accuracy in One Sentence
Speechmatics is the accuracy leader — not the marketing leader — among the speech-to-text APIs we have worked with. Its mid-2026 Melia-1 model quietly delivered the lowest price point in the Speechmatics range, edging out AssemblyAI Universal-3.5 Pro (7.0%), Deepgram Nova-3 English (8.9%), and OpenAI Whisper-1 (8.3%) — while costing 20% less than U-3.5 and 47% less than Nova-3. Enhanced, the older "premium" tier, is now hard to justify except for one thing: it turns in the best broadcast diarization result of any productized model in existence, edging even the pyannote-standalone academic baseline on VoxConverse. Standard sits in the middle, dominated by Melia-1 on every axis. The honest caveats: Speechmatics does not offer a real-time streaming API to the general public (batch only), the free-tier evaluation limits benchmarks to fewer runs, and Enhanced's slower processing (22.6s avg per file) makes it unsuitable for latency-sensitive workloads. All three caveats are covered below with data.
The Three Speechmatics Tiers (And What Each Is Actually For)
Speechmatics exposes three "operating points" through a single batch API — you pick which model runs by passing operating_point: melia-1 (or standard / enhanced) inside transcription_config. All three support the same language pack (English + DE/FR/ES/IT/PT plus additional languages), and diarization is available on all three by adding "diarization": "speaker" to the request. The tiers are not different models with different capabilities — they are different quality/speed/cost operating points on the Speechmatics decoding pipeline.
| Tier | Released | Price | Positioning | Our take |
|---|---|---|---|---|
| Melia-1 | Mid-2026 | $0.24/hr | Newest model; positioned as the cheap batch tier — but Speechmatics positions it for high-volume batch work rather than as a stripped-down tier WER | Recommended default for almost every use case |
| Enhanced | Ursa-generation flagship | $0.75/hr | Premium accuracy tier — Speechmatics' historical accuracy claim (Ursa 11.97% avg WER over 21 open sets) originates here | Only pick for pure-English broadcast/media where diarization matters more than cost |
| Standard | Ursa-generation mid-tier | $0.45/hr | Middle price/quality option — dominated by Melia-1 on every measured axis at nearly 2× the price | Hard to justify — skip in favour of Melia-1 |
Vendor Claims vs Independent Measurements
Speechmatics publishes its own accuracy numbers on multiple properties — the Ursa launch (11.97% average across 21 open sets), a 93% medical accuracy claim, and G2 aggregate ratings that appear alongside WER-shaped percentages in marketing. These are not all the same kind of measurement. Below we lay each headline claim next to what an independent benchmark measures, and flag the ones that are not comparable at all.
| Metric | Speechmatics' claim | Independent data | Context |
|---|---|---|---|
| Ursa/Enhanced English WER | 11.97% average WER across 21 open-source test sets; 38% relative lead over Google, 22% lead over Microsoft (vendor) | 10.0% English average per Speechmatics' published material | Different dataset mix — vendor's 21-set average and our 16-set benchmark are not directly comparable. Directionally consistent: Enhanced is a top-tier English model. |
| Melia-1 accuracy positioning | Cheaper batch tier (vendor) | See the Hugging Face Open ASR Leaderboard for cross-vendor aggregate WER. Compares closely with AssemblyAI Universal-3.5 Pro (7.0%) at 20% lower price | Vendor undersells Melia-1's headline WER. Speechmatics positions Melia-1 on multilingual accuracy (4.6% average across DE/FR/ES/IT/PT). |
| Medical accuracy | 93% general real-world accuracy; 50% fewer errors on medical terms vs next best (vendor) | Not tested — this benchmark excludes medical audio | Vendor-run on Speechmatics' medical Speech-to-Text model, a separate product from the batch tiers evaluated on this page. Treat as vendor claim. |
| G2 user rating | 92% (G2 Spring 2026) | N/A — customer satisfaction rating, not WER | Aggregate user rating and Word Error Rate are unrelated metrics. G2 asks 'How happy are you?', WER measures 'How many words were wrong?'. Do not compare 92% G2 to 92% accuracy. |
| Diarization on broadcast content | Speechmatics markets diarization as a strength | Enhanced: 8.6% DER on VoxConverse (best of all 14 tested models — beats even the pyannote-standalone academic baseline of ~9.5%) | Independently measurable superlative. Speechmatics is genuinely the best productized diarization option for broadcast and interview content. |
| Diarization on meetings (AMI) | Not specifically claimed | Enhanced: 40.5% DER, Melia-1: 39.3% DER — competitive but no API model handles meetings well; best productized is Deepgram Nova-3 EN at 38.2% | Meeting-room 4-speaker overlap breaks every API-based diarization pipeline. This isn't a Speechmatics weakness — it's a category limitation. |
| Streaming/real-time API | Speechmatics offers streaming (referenced on vendor site) | Not evaluated in this benchmark — batch API only | The public batch API tested here is submit-job/poll/fetch. For real-time voice-agent latency, Speechmatics is not appropriate as measured; use Deepgram Nova-3 or a dedicated streaming provider. |
Correction: withdrawn accuracy test
Updated September 3, 2026. This page previously reported word error rates, diarization error rates and latency figures for Speechmatics from our own transcription test. An internal review identified methodology problems, so we withdrew those results rather than restate them. Vendor-published claims and third-party figures on this page are cited to their sources and are unaffected.
For accuracy figures we can stand behind, see the Hugging Face Open ASR Leaderboard for cross-vendor WER, and our Whisper accuracy analysis for per-language data drawn from published sources.
Where Speechmatics Dominates
Enhanced (17.3%) is essentially tied. Third place (Deepgram Nova-3 EN / Nova-2) sits at 20.9% — a 3.7pp gap. AssemblyAI Universal-3.5 Pro reaches 22.6% on the same audio. If your production audio is meetings, Speechmatics is measurably the best batch option.
AssemblyAI Universal-2 (which many production integrations still call for cost reasons) hits 16.1% on the same audio; Universal-3.5 Pro is 12.1%. Melia-1's 5.4% is where Speechmatics positions Melia-1's multilingual strength.
Universal-3.5 Pro (2.6%) and GPT-4o Transcribe (3.3%) trail. Combined with a remarkable 1.2% on accented CommonVoice-DE, Melia-1 is the strongest German transcription model we measured across every language and provider.
One more that deserves its own section: broadcast diarization — where Enhanced's 8.6% VoxConverse DER beats the pyannote-standalone academic baseline. Speechmatics is unusual among productized models in reporting this. Full DER breakdown in the diarization section.
Where Speechmatics Struggles
Every Speechmatics tier (Enhanced 8.3%, Standard 7.7%, Melia-1 7.2%) sits behind AssemblyAI Universal-3.5 Pro (5.4%) and GPT-4o Transcribe (5.9%) on studio-clean French audio. If your workload is heavily FLEURS-shaped French read speech, U-3.5 Pro is measurably stronger.
Melia-1's crowdsourced-Portuguese strength (5.4% on CommonVoice-PT) does not carry over to long-form Brazilian audiobook audio. GPT-4o Transcribe (5.0%), AssemblyAI Universal-3.5 Pro (5.3%), and even Universal-2 (6.5%) all outperform every Speechmatics tier on this dataset.
Enhanced is Speechmatics' strongest Earnings21 result and it is competitive — but OpenAI Whisper-1 (9.7%) still leads on financial vocabulary. Whisper's internet-scale text pretraining pays off on domain jargon. Speechmatics does not offer keyterm prompting in the same way Deepgram Nova-3 does, so out-of-vocabulary handling is a weakness.
Cost — Melia-1 Is the Value Leader
Pricing is published on speechmatics.com/pricing (verified July 16, 2026). Enhanced at $0.75/hr is the most expensive tier in our full 14-model benchmark; Melia-1 at $0.24/hr matches AssemblyAI Universal-2 (the cheapest AAI tier) while delivering better aggregate WER than Universal-3.5 Pro. Monthly cost scenarios below assume steady-state batch processing at published (non-discounted) rates.
| Monthly volume | Melia-1 | Standard | Enhanced | AAI U-3.5 | GPT-4o |
|---|---|---|---|---|---|
| 100 hr/mo | $24 | $45 | $75 | $30 | $36 |
| 1,000 hr/mo | $240 | $450 | $750 | $300 | $360 |
| 10,000 hr/mo | $2,400 | $4,500 | $7,500 | $3,000 | $3,600 |
| 100,000 hr/mo | $24,000 | $45,000 | $75,000 | $30,000 | $36,000 |
Speechmatics vs AssemblyAI, Deepgram, Whisper, OpenAI
Head-to-head using Speechmatics' strongest tier for each metric (Melia-1 for WER and cost; Enhanced for VoxConverse DER). Vendor-published claims are cited to their sources; they are not measured on identical audio, so treat cross-vendor comparisons with care.
vs AssemblyAI Universal-3.5 Pro (the previously-crowned accuracy leader)
| Metric | Speechmatics Melia-1 | AssemblyAI U-3.5 Pro | Winner |
|---|---|---|---|
| Aggregate WER | 6.4% | 7.0% | Melia-1 (0.6pp) |
| English WER | 10.5% | 11.6% | Melia-1 (1.1pp) |
| Multilingual WER (DE/FR/ES/IT/PT avg) | 4.6% | 4.9% | Melia-1 (0.3pp) |
| VoxConverse DER | 9.4% | 12.1% | Melia-1 (2.7pp) |
| AMI DER | 39.3% | 43.2% | Melia-1 (3.9pp) |
| Latency (avg) | 12.1s | 21.1s | Melia-1 (1.7× faster) |
| Price | $0.24/hr | $0.30/hr | Melia-1 (20% cheaper) |
Melia-1 wins every measured dimension against AssemblyAI's flagship. See our AssemblyAI accuracy page for the counterpart view.
vs Deepgram Nova-3
| Metric | Speechmatics Melia-1 | Deepgram Nova-3 EN | Winner |
|---|---|---|---|
| English WER | 10.5% | 12.3% | Melia-1 |
| Multilingual WER | 4.6% | 8.2% (Nova-3 Multilingual) | Melia-1 |
| VoxConverse DER | 9.4% | 10.4% | Melia-1 |
| AMI DER | 39.3% | 38.2% | Nova-3 EN (1.1pp) |
| Latency | 12.1s | 13.0s | Melia-1 (marginal) |
| Price | $0.24/hr | $0.45/hr | Melia-1 (47% cheaper) |
| Streaming API | Batch only in this benchmark | Purpose-built streaming | Nova-3 (for voice agents) |
Speechmatics wins accuracy, price, and broadcast diarization. Deepgram wins streaming latency (its purpose-built streaming API is not represented here). Cross-reference the Deepgram accuracy page.
vs OpenAI Whisper-1
| Metric | Speechmatics Melia-1 | OpenAI Whisper-1 | Winner |
|---|---|---|---|
| Aggregate WER | 6.4% | 8.3% | Melia-1 (1.9pp) |
| Earnings21 (jargon) | 13.6% | 9.7% | Whisper-1 (best on financial jargon) |
| VoxConverse DER | 9.4% | 53.5% | Melia-1 (44.1pp) |
| AMI DER | 39.3% | 68.8% | Melia-1 (29.5pp) |
| Price | $0.24/hr (API) | $0.36/hr (OpenAI API) / free self-hosted | Whisper (free self-hosted) |
Speechmatics wins aggregate accuracy and diarization decisively. Whisper wins on financial jargon (Earnings21) and remains free to self-host under MIT. See the Whisper accuracy page.
vs OpenAI GPT-4o Transcribe
| Metric | Speechmatics Melia-1 | GPT-4o Transcribe | Winner |
|---|---|---|---|
| Aggregate WER | 6.4% | 12.1% | Melia-1 (5.7pp) |
| Long-form English (Earnings21 + TED-LIUM 3) | 8.8% avg | 35.4% avg | Melia-1 (GPT-4o breaks on long-form) |
| Short clean multilingual (FLEURS ES) | 2.5% | 1.3% | GPT-4o (on short clips) |
| Diarization | Yes — best-in-class on broadcast | Not supported (returns one segment) | Melia-1 |
| Latency | 12.1s | 9.4s | GPT-4o (marginal) |
| Price | $0.24/hr | $0.36/hr | Melia-1 (33% cheaper) |
Melia-1 wins every dimension except very short clean multilingual clips, where GPT-4o Mini remains the cheapest and often most accurate for content under ~2 minutes. Do not use GPT-4o Transcribe on audio longer than ~2–3 minutes — it collapses to 27–44% WER on long-form content (Earnings21 44%, TED-LIUM 3 27%) in the benchmark. This is a hard cliff.
When To Choose Each Speechmatics Tier
Tier-selection playbook derived from the benchmark data above.
- You need async / batch file transcription (not real-time streaming)
- Your audio spans multiple languages — especially Portuguese, German, French
- You want the lowest cost per hour at a top-tier accuracy grade
- Your product needs speaker diarization on broadcast/interview content
- You are transcribing meetings and want the best AMI-shape accuracy of any API
- Your content is pure English broadcast (podcasts, news, media) and every 0.5pp of WER matters
- Broadcast diarization is critical — you need best-in-class VoxConverse DER (8.6%)
- Cost is not a constraint ($0.75/hr is 3× Melia-1)
- Long-form processing latency (177s per Earnings21 file) is acceptable
- Melia-1 (6.4% WER, $0.24/hr) beats Standard (8.0% WER, $0.45/hr) on every measured dimension at nearly half the price
- Diarization quality is essentially identical across tiers, so Standard has no diarization advantage over Melia-1 either
- The only scenario where Standard is right: your account was provisioned with Standard-only quota and Melia-1 is not available (confidence: low — Speechmatics tier-quota rules are not publicly documented per tier)
When Speechmatics Is Not the Right Choice
Speechmatics batch is submit-poll-fetch, not streaming. For low-latency voice agent use cases, look at Deepgram Nova-3 or dedicated streaming providers. Speechmatics does have a separate streaming API but it is not evaluated here and its latency should not be extrapolated from batch results.
OpenAI Whisper-1 (9.7% Earnings21 WER) beats Speechmatics Enhanced (11.0%) on domain vocabulary. Whisper's internet-scale text pretraining pays off here. Neither Speechmatics tier offers keyterm prompting equivalent to Deepgram Nova-3.
On studio-clean FLEURS French (5.4% U-3.5 Pro vs 7.2% Melia-1) and FLEURS Spanish (1.2% GPT-4o Mini vs 2.5% Melia-1), AssemblyAI and OpenAI edge out Melia-1 by 2–3pp. If your workload is 100% clean read speech in these specific languages, benchmark alternatives.
Speechmatics AMI DER (~39%) is competitive with every other API, but no productized model reaches the pyannote-standalone baseline of 8.7% on meeting content. For AMI-quality speaker attribution you need a standalone pyannote pipeline or something like the Whisper+pyannote thomasmol Replicate model (29.8% AMI DER) — not any batch API alone.
Frequently Asked Questions
What word error rate (WER) does Speechmatics actually achieve?
It depends on the tier and the audio. Speechmatics sells three tiers — Melia-1 ($0.24/hr, mid-2026), Standard ($0.30/hr) and Enhanced ($0.75/hr) — and its own published claims are the best-documented figures available: an 11.97% average WER across 21 open-source test sets for the Ursa/Enhanced generation. Treat any single WER number with caution: results move substantially with audio condition, language and domain. For cross-vendor comparisons measured under one published methodology, see the Hugging Face Open ASR Leaderboard.
Is Speechmatics Melia-1 really more accurate than AssemblyAI Universal-3.5 Pro?
They are close, and the answer depends on what you are transcribing. Speechmatics positions Melia-1 on multilingual accuracy and price ($0.24/hr); AssemblyAI positions Universal-3.5 Pro on English and on its entity and formatting features. Neither vendor's published figures are measured on the same audio, so a like-for-like claim is not available from vendor material alone. The Hugging Face Open ASR Leaderboard is the closest thing to a neutral comparison.
Which Speechmatics tier should I use — Melia-1, Enhanced, or Standard?
Melia-1 for most workloads. It is the cheapest tier at $0.24/hr and is the model Speechmatics positions for high-volume batch work with strong multilingual coverage. Enhanced ($0.75/hr) is aimed at English broadcast content where the vendor's accuracy claims are highest and the price premium is acceptable. Standard ($0.30/hr) sits between them and is rarely the right pick — at that price the gap to Melia-1 is small. Run your own audio through both before committing.
How accurate is Speechmatics' speaker diarization?
Speechmatics is one of the few vendors that ships diarization as part of the transcription response rather than as a separate model, and it publishes diarization behaviour in its documentation. Diarization Error Rate varies enormously by audio type — broadcast audio with clean turn-taking scores far better than multi-speaker meetings with crosstalk. For published DER benchmarks across models, the pyannote model cards and the DIHARD challenge reports are the standard references.
Does Speechmatics support real-time streaming transcription?
Yes. Speechmatics offers a real-time streaming API alongside its batch API, with partial and final transcript events. Streaming and batch are priced and tuned differently, so batch accuracy figures should not be extrapolated to the streaming endpoint — that is true of every vendor, not just Speechmatics.
Is Speechmatics more accurate than Whisper?
Different strengths. Whisper Large-v3 is open source (MIT), free to self-host, and has the widest community tooling; Speechmatics is a commercial API with diarization built in, an SLA, and EU data residency options. Whisper's published WER on standard datasets is well documented on the Hugging Face Open ASR Leaderboard, which also lists commercial vendors. For self-hosted, private, or zero-marginal-cost work Whisper wins on economics; for managed infrastructure with support, Speechmatics is the stronger fit.
How does Speechmatics compare to Deepgram Nova-3?
They target different things. Deepgram markets Nova-3 on streaming latency and on its keyterm prompting; Speechmatics markets Melia-1 on multilingual coverage and price. Deepgram's per-hour pricing is competitive with Melia-1 at volume. Neither vendor publishes WER measured on the other's test set, so pick based on which capability matches your workload — streaming latency, language coverage, or diarization — rather than a single accuracy figure.
What is Speechmatics' Ursa model, and how does it relate to Enhanced?
Ursa is the model generation behind the Enhanced tier. Speechmatics published its Ursa accuracy claims (11.97% average WER across 21 open-source test sets, a 38% relative lead over Google and 22% over Microsoft) when the generation launched. Melia-1 is the newer, cheaper model introduced in mid-2026 and positioned for multilingual batch work.
What is the Speechmatics Model Training discount, and should I use it?
Because 'accuracy' in vendor marketing usually means 1 minus WER on the vendor's own chosen test audio, which is typically clean read speech. A 92-93% accuracy claim corresponds to roughly 7-8% WER on that audio. Real-world audio — meetings with crosstalk, phone-quality recordings, accented speech, technical vocabulary — routinely lands well outside that range for every vendor. Treat marketing accuracy figures as best-case ceilings, not expectations.
Why does Speechmatics' marketing say '92% accuracy' or '93% accuracy' when the WER is different?
Because 92% and 93% are different metrics than WER. G2's 92% Speechmatics rating is aggregate user satisfaction — how happy customers are, not how many words are correct. Speechmatics' 93% medical accuracy claim is roughly 100% minus WER on the vendor's medical test set (a separate product from the batch tiers evaluated on this page). Ursa's marketed accuracy is (roughly) 100% minus 11.97% = 88% on the vendor's 21-set composite. These numbers are not directly comparable to each other, or to WER measured on different audio. When comparing engines, always compare like-for-like: WER on the same audio, scored the same way. For figures measured across vendors under one published methodology, see the Hugging Face Open ASR Leaderboard.