Pure infrastructure for bilingual products

The translation engine underneath your product.

Speech-to-Text. Translation. Text-to-Speech. One API. Built for developers who are serious about language.

Get API Key Read the Docs

request

How it works

Three steps. One call.

01 — Listen

Whisper-powered STT converts spoken audio to text in real time.

transcript = await excelsior.listen(audio_url)

02 — Translate

Accurate Spanish ↔ English translation returned instantly.

translation = result.to('en')

03 — Speak

Clean TTS audio your frontend plays directly.

audio.play(result.audio_url)

API reference preview

One endpoint for the entire conversation pipeline.

Send source audio once. Receive normalized transcript, translated text, and playable speech output in the same response.

POST /v1/conversation HTTP/1.1
Authorization: Bearer exc_live_••••••••
Content-Type: application/json

{
  "audio_url": "https://cdn.acmehealth.com/intake/es-458.wav",
  "source_lang": "es",
  "target_lang": "en",
  "voice": "alloy"
}

Built for builders

Infrastructure, not a consumer app.

Excelsior is not a consumer app. It is the layer your product sits on top of. If you are building a bilingual communication tool, a localization feature, or a customer-facing language product in Latin America, Excelsior gives you the engine without the complexity.

Low latency under 800ms
Self-hosted Whisper core
Simple REST API
Predictable pricing for each lane

Who are you building for?

One engine. Two ways to use it.

Whether you're building directly on the API or distributing to businesses at scale, Excelsior has a lane for you.

Developers

You're building a product.

Pay only for what you use.

Plan	Interactions/mo	Per 1k
Starter	0 - 10,000	$0.80
Growth	10,001 - 50,000	$0.60
Scale	50,001 - 200,000	$0.40
Enterprise	200,000+	Custom

Get API Key

No per-business fees. Pure usage.

Resellers

You're distributing to businesses.

Pay per active client, nothing else.

Tier	Per Business/mo
Standard	$5.00
Partner	Contact us
Enterprise	Custom

Become a Partner

No usage tracking. No interaction counting. Flat and predictable.

Not sure which lane you're in? → contact@useexcelsior.com

Partners

Built for resellers and builders.

Excelsior works with companies who distribute bilingual communication tools to small businesses. Bring the relationships, brand, and workflow. We provide the speech, translation, and audio layer behind it.

Become a Partner

Get API access

Tell us what you're building.

We partner with teams building serious language products, reseller platforms, and internal communication tools.