B
VoiceMPP
Preview responses and set spending limits for this service through use.mpp.land
Free budget controls, response samples, and reliability routing.
Compliance Checks
All paid ops declare 402 response
MUST
10pt
All x-payment-info valid
MUST
10pt
Challenge has Cache-Control: no-store
MUST
5pt
Challenge digest on POST
SHOULD
3pt
Challenge has expires
SHOULD
3pt
Challenge has Problem Details
SHOULD
2pt
Challenge has required params
MUST
5pt
Challenge has WWW-Authenticate
MUST
5pt
Challenge returns 402
MUST
10pt
Correct Content-Type
MUST
5pt
Has Cache-Control on discovery
SHOULD
5pt
Has input schemas
SHOULD
5pt
Has llms.txt
SHOULD
5pt
Has /openapi.json at root
MUST
10pt
Has required top-level fields
MUST
10pt
Served over HTTPS
MUST
10pt
Uses standard categories
SHOULD
2pt
Paid Operations (4)
GET /api/tts dynamic
TTS payment probe
Returns 402 with payment challenge. Use POST with payment to synthesize speech.
- Amount
- 0.050000
- Currency
- -
- Method
- mpp
- Intent
- -
- 402 Declared
- Yes
Non-standard x-payment-info fields:
price: 0.050000 pricingMode: fixed protocols: [mpp]
Input Schema
| Field | Type | Required | Description |
|---|---|---|---|
| speed | number | No |
Speech speed multiplier.
default: 1
|
| text | string | Yes | Text to synthesize into speech. Maximum 5000 characters. |
| voice | string | No |
Voice model ID.
default: en_US-amy-medium
|
POST /api/tts dynamic
Convert text to speech audio
Synthesize text into WAV audio using Piper TTS. Fixed price: $0.05 per request (up to 5000 characters). Supports 9 voices across 8 languages with configurable speed, expressiveness, and pausing.
- Amount
- 0.050000
- Currency
- -
- Method
- mpp
- Intent
- -
- 402 Declared
- Yes
Non-standard x-payment-info fields:
price: 0.050000 pricingMode: fixed protocols: [mpp]
Input Schema
| Field | Type | Required | Description |
|---|---|---|---|
| noiseScale | number | No |
Controls expressiveness and emotion variation. 0 = monotone, 1 = very expressive.
default: 0.667
|
| noiseW | number | No |
Phoneme-level duration variation. Higher = more natural rhythm.
default: 0.8
|
| sentenceSilence | number | No |
Seconds of silence inserted between sentences.
default: 0.2
|
| speaker | integer | No | Speaker ID for multi-speaker voice models. |
| speed | number | No |
Speech speed multiplier. 1.0 = normal, 0.5 = half speed, 2.0 = double speed.
default: 1
|
| text | string | Yes | Text to synthesize into speech. Maximum 5000 characters. |
| voice | string | No |
Voice model ID. Call GET /api/voices to list available voices.
default: en_US-amy-medium
|
Response Schema (200)
{
"format": "binary",
"type": "string"
}GET /api/stt dynamic
STT payment probe
Returns 402 with payment challenge. Use POST with payment and audio file to transcribe.
- Amount
- 0.010000
- Currency
- -
- Method
- mpp
- Intent
- -
- 402 Declared
- Yes
Non-standard x-payment-info fields:
price: 0.010000 pricingMode: fixed protocols: [mpp]
Input Schema
| Field | Type | Required | Description |
|---|---|---|---|
| file | string (binary) | Yes | Audio file (mp3, wav, m4a, webm, ogg, flac). Max 25MB. |
| language | string | No | ISO 639-1 language code hint. |
POST /api/stt dynamic
Transcribe audio to text
Transcribe an audio file to text using whisper.cpp. Fixed price: $0.01 per request. Supports mp3, wav, m4a, webm, ogg, flac formats up to 25MB.
- Amount
- 0.010000
- Currency
- -
- Method
- mpp
- Intent
- -
- 402 Declared
- Yes
Non-standard x-payment-info fields:
price: 0.010000 pricingMode: fixed protocols: [mpp]
Input Schema
| Field | Type | Required | Description |
|---|---|---|---|
| file | string (binary) | Yes | Audio file to transcribe. Supported: mp3, wav, m4a, webm, ogg, flac. Max 25MB. |
| language | string | No | ISO 639-1 language code hint (e.g. en, zh, fr, de, es, vi, pt, ru, ja, ko). Omit for auto-detection. |
Response Schema (200)
| Field | Type | Description |
|---|---|---|
| duration | number | Processing time in seconds. |
| language | string | Detected or specified language code. |
| text | string | Transcribed text content. |
Payment Methods
- Methods
- tempo (from challenge)
- Intents
- charge (from challenge)
- Currencies (discovery)
- -
- Currency (challenge)
- USDC.e on Tempo (Tempo)
- Multiple Challenges
- No
Recipients
- 0x0cd269016873f3d1F1Dd1B69819982f2dD83e4b8
Per-endpoint breakdown
- GET /api/stt
- 0x0cd269016873f3d1F1Dd1B69819982f2dD83e4b8
- GET /api/tts
- 0x0cd269016873f3d1F1Dd1B69819982f2dD83e4b8
- POST /api/stt
- 0x0cd269016873f3d1F1Dd1B69819982f2dD83e4b8
- POST /api/tts
- 0x0cd269016873f3d1F1Dd1B69819982f2dD83e4b8
Security
- TLS Version
- TLSv1.3
- Challenge ID Unique
- Yes
- Challenge ID Length
- 43
- Digest Binding
- -
Uptime
- Discovery
- Reachable (11ms)
- Challenge
- Reachable (11ms)
- Last Checked
Schema Completeness
- Paid Operations
- 4
- With Input Schema
- 4
- With Description
- 4
Documentation
- Homepage
- -
- API Reference
- -
- llms.txt
- -
Discovery
- OpenAPI URL
- https://voicempp.shelmail.xyz/openapi.json
- OpenAPI Version
- 3.1.0
- Service Version
- 1.0.0
- Document Size
- 11035 bytes
- Document Hash
- c035c472bed37f6c30bf88044b5a179f616b6d4ece4e44e26734044267daf452
Version History (2 snapshots)
Scan snapshots
| Date | Grade | Score | Response | Status |
|---|---|---|---|---|
| 2026-04-06 | B | 78% | 200ms | Up |
| 2026-04-07 | B | 78% | 240ms | Up |