# Prelude

**Canonical:** https://apis.io/providers/prelude-so/  
**Website:** https://prelude.so  
**APIs profiled:** 1

Prelude is a phone and email verification API - "the trust layer between your signups and your business." Its Verify API creates and checks one-time passcodes (OTP) across SMS, WhatsApp, RCS, Viber, and voice in 230+ countries, with smart multi-provider routing and built-in anti-fraud. Alongside Verify, Prelude offers Notify (transactional messaging), Lookup / Intel (phone number intelligence - line type, carrier, ported and temporary flags, CNAM), and Watch (anti-fraud risk prediction and feedback). The public REST API v2 lives at https://api.prelude.dev/v2 with Bearer API-key auth and official SDKs for Python, Node.js, Java, and Go. Prelude positions itself as a developer-first alternative to Twilio Verify.

## Kin Score — 37.0 / 100 (thin)

Scored 2026-08-30 under rubric 0.17.2. Trend: flat (-0.6 from 37.6).

| Facet | Score |
|---|---|
| Discoverability | 68.5 |
| Contract Quality | 56.8 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 31.6 |
| Developer Ergonomics | 35.7 |
| Commercial Clarity | 39.5 |
| Access Clarity | 39.5 |

Regulatory layer — **Telecommunications**: 8.3 (matched via tags).

## Agent readiness — 19.8 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | derived |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | bearer |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |
| Delegated Identity | no |
| Protected Resource Metadata | no |
| Dynamic Client Registration | no |
| Agentic Commerce | no |

## Access

Paid · Self-serve signup — onboarding: self-serve, pricing: paid, trial: no (confidence: high).

## APIs (4)

- **Prelude Lookup API** — Phone number intelligence - line type, carrier, and flags.
- **Prelude Transactional API** — Send transactional messages over SMS, RCS, and WhatsApp.
- **Prelude Verification API** — Create and check one-time passcode (OTP) verifications.
- **Prelude Watch API** — Anti-fraud risk prediction and outcome feedback.

## Agentic access (1)

- **Prelude So Agentic Access** — 7 operations · 6 acting · 1 human-in-the-loop

## Security (1)

- **Prelude So Authentication** — http · 1 scheme

## Plans (1)

- **Prelude So Plans Pricing**

## Tags

Number Verification, Phone Verification, OTP, Authentication, Anti-Fraud, Two-Factor Authentication, SMS, Phone Number Lookup

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/prelude-so/). Scores are computed from the provider's own public artifacts under a published rubric.