B

StablePhone

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
1 issue
  • POST endpoint challenge missing digest parameter (SHOULD per spec)

Paid Operations (4)

POST /api/call dynamic
Make an AI phone call ($0.54). Send a phone number and task, get back a call_id to track status. Returns 403 if the number is on the Do-Not-Call (DNC) list — do not retry DNC numbers.
Amount
map[amount:0.54 currency:USD mode:fixed]
Currency
-
Method
Intent
-
402 Declared
Yes
Non-standard x-payment-info fields: price: map[amount:0.54 currency:USD mode:fixed] protocols: [map[x402:map[]] map[mpp:map[currency:0x20c0000000000000000000000000000000000001 intent:charge method:tempo]]]

Input Schema

FieldTypeRequiredDescription
first_sentence string No
from string No
max_duration integer No
metadata object No
model string No
enum: base, turbo
phone_number string Yes
record boolean No
task string Yes
transfer_phone_number string No
voice string No
voicemail_action string No
enum: hangup, leave_message, ignore
voicemail_message string No
wait_for_greeting boolean No

Response Schema (200)

FieldTypeDescription
call_id string -
message string -
success boolean -
POST /api/number dynamic
Buy a phone number ($20.00 via x402). Use it as outbound caller ID.
Amount
map[amount:20.00 currency:USD mode:fixed]
Currency
-
Method
Intent
-
402 Declared
Yes
Non-standard x-payment-info fields: price: map[amount:20.00 currency:USD mode:fixed] protocols: [map[x402:map[]] map[mpp:map[currency:0x20c0000000000000000000000000000000000001 intent:charge method:tempo]]]

Input Schema

FieldTypeRequiredDescription
area_code string No
country_code string No
enum: US, CA
default: US

Response Schema (200)

FieldTypeDescription
expires_at string -
phone_number string -
success boolean -
POST /api/number/topup dynamic
Extend a phone number by 30 days from current expiry ($15.00 via x402). Top-ups stack. Anyone can top up any number.
Amount
map[amount:15.00 currency:USD mode:fixed]
Currency
-
Method
Intent
-
402 Declared
Yes
Non-standard x-payment-info fields: price: map[amount:15.00 currency:USD mode:fixed] protocols: [map[x402:map[]] map[mpp:map[currency:0x20c0000000000000000000000000000000000001 intent:charge method:tempo]]]

Input Schema

FieldTypeRequiredDescription
phone_number string Yes

Response Schema (200)

FieldTypeDescription
expires_at string -
phone_number string -
success boolean -
POST /api/lookup dynamic
Check if a phone number has iMessage/FaceTime ($0.05 via x402). Returns a token to poll for async results.
Amount
map[amount:0.05 currency:USD mode:fixed]
Currency
-
Method
Intent
-
402 Declared
Yes
Non-standard x-payment-info fields: price: map[amount:0.05 currency:USD mode:fixed] protocols: [map[x402:map[]] map[mpp:map[currency:0x20c0000000000000000000000000000000000001 intent:charge method:tempo]]]

Input Schema

FieldTypeRequiredDescription
phone_number string Yes

Response Schema (200)

FieldTypeDescription
token string -

Payment Methods

Methods
tempo (from challenge)
Intents
charge (from challenge)
Currencies (discovery)
-
Currency (challenge)
USDC.e on Tempo (Tempo)
Multiple Challenges
No

Recipients

  • 0xD219dB8179Bb9C1899eF87f39eebA9D1070c6801
Per-endpoint breakdown
POST /api/call
0xD219dB8179Bb9C1899eF87f39eebA9D1070c6801
POST /api/lookup
0xD219dB8179Bb9C1899eF87f39eebA9D1070c6801
POST /api/number
0xD219dB8179Bb9C1899eF87f39eebA9D1070c6801
POST /api/number/topup
0xD219dB8179Bb9C1899eF87f39eebA9D1070c6801

Security

TLS Version
TLSv1.3
Challenge ID Unique
Yes
Challenge ID Length
43
Digest Binding
-

Uptime

Discovery
Reachable (2110ms)
Challenge
Reachable (387ms)
Last Checked

Schema Completeness

Paid Operations
4
With Input Schema
4
With Description
4

Documentation

Homepage
-
API Reference
-
llms.txt
-

Discovery

OpenAPI URL
https://stablephone.dev/openapi.json
OpenAPI Version
3.1.0
Service Version
1.0.0
Document Size
16712 bytes
Document Hash
bf62d4e01ea31ccfcf58be1f0bbe952d4f2b36cdaa0e9b567733238e475b10e4

Version History (2 snapshots)

  • document hash changed (no semantic differences detected)
  • document hash changed (no semantic differences detected)
  • document hash changed (no semantic differences detected)
  • document hash changed (no semantic differences detected)
  • price changed on POST /api/call: None → {'mode': 'fixed', 'currency': 'USD', 'amount': '0.54'}
  • price changed on POST /api/lookup: None → {'mode': 'fixed', 'currency': 'USD', 'amount': '0.05'}
  • price changed on POST /api/number: None → {'mode': 'fixed', 'currency': 'USD', 'amount': '20.00'}
  • price changed on POST /api/number/topup: None → {'mode': 'fixed', 'currency': 'USD', 'amount': '15.00'}
Scan snapshots
Date Grade Score Response Status
2026-04-06 B 79% 322ms Up
2026-04-07 B 79% 2456ms Up