# Playground API — Free Stateful Mock REST & GraphQL Service

**Canonical:** https://apis.io/providers/playground/  
**Website:** https://playground.nileslabs.com  
**APIs profiled:** 2

A free, zero-configuration, stateful mock REST and GraphQL API sandbox by Nilesh Kumar / Niles Labs. Unlike static mock APIs, it provides stateful per-session virtual mutation overlays where POST/PUT/PATCH/DELETE mutations persist across GET queries within a session, while the global baseline dataset remains read-only. Includes chaos/network simulation, dynamic collections, avatar/thumbnail generators, and simulated JWT auth loops. MIT licensed, no auth or signup required.

## Kin Score — 31.5 / 100 (thin)

Scored 2026-09-14 under rubric 0.22.0.

| Facet | Score |
|---|---|
| Discoverability | 66.7 |
| Contract Quality | 42.6 |
| Contract Governance | 4.5 |
| Operational Transparency | 5.3 |
| Developer Ergonomics | 47.0 |
| Access Clarity | 21.1 |

## Agent readiness — 21.8 (agent-aware)

| Dimension | Value |
|---|---|
| Spec Presence | yes |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | bearer |
| Idempotency | no |
| Error Semantics | documented |
| OpenAPI Examples | no |
| Rate Limit Signal | documented |
| Event Surface Described | no |
| Agent Skills | derived |
| 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 |

## APIs (2)

- **Playground REST API** — Free stateful mock REST API with session-scoped mutation overlays, dynamic collections, media generators, chaos simulation, and simulated JWT auth. Canonical HTTPS base is playg...
- **Playground GraphQL API** — GraphQL gateway providing stateful mock query and mutation access to the same dataset, with an interactive explorer.

## MCP servers (1)

- **Playground API — Free Stateful Mock REST & GraphQL Service MCP Server**

## Security (2)

- **Playground Authentication** — 1 scheme
- **Playground Domain Security** — TLSv1.3 · HSTS · DMARC

## Plans (1)

- **Playground Plans Pricing**

## Tags

Developer Tools, Testing, Mock API, api-sandbox, REST, GraphQL, E2E Testing

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