# Arena Trading API

**Canonical:** https://apis.io/apis/arena-predictions-com/arena-predictions-com-trading-api/  
**Provider:** Arena — https://apis.io/providers/arena-predictions-com/  
**Base URL:** https://arena-predictions.com/api/v1  
**Documentation:** https://docs.arena-predictions.com/

Arena Trading API is one of 8 APIs that [Arena](https://apis.io/providers/arena-predictions-com/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. This API exposes 6 JSON Schema definitions. Tagged areas include Trading. The published artifact set on APIs.io includes an OpenAPI specification and 6 JSON Schemas.

Place and cancel paper orders for the key owner. Scope trade:write, which a key carries only when its creator asked for it. Send X-Arena-Org to trade that organization's paper sandbox. Paper is the default: nothing is sent to a venue unless execution is kalshi (trade:write:kalshi), poly-intl (trade:write:poly-intl, Polymarket International only) or prophetx (trade:write:prophetx, the key owner's own ProphetX connection; switched off until Arena opens it). Polymarket US is not offered.

## Operations (3)

| Method | Path | Summary |
|---|---|---|
| POST | `/portfolio/orders` | Place a paper order |
| DELETE | `/portfolio/orders/{orderId}` | Cancel a paper order |
| POST | `/portfolio/orders/{orderId}/amend` | Amend a live Kalshi order |

## Machine-readable artifacts (7)

- **OpenAPI** — https://artifacts.apis.io/arena-predictions-com/openapi/arena-predictions-com-trading-api-openapi.yml
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-order-request-schema.json
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-owner-scoreboard-response-schema.json
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-instrument-book-schema.json
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-order-result-schema.json
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-track-record-response-schema.json
- **JSONSchema** — https://artifacts.apis.io/arena-predictions-com/json-schema/arena-predictions-com-me-schema.json

## Other Arena APIs (7)

- [Arena API keys API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-api-keys-api/)
- [Arena Identity API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-identity-api/)
- [Arena Markets API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-markets-api/)
- [Arena Portfolio API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-portfolio-api/)
- [Arena Records API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-records-api/)
- [Arena Status API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-status-api/)
- [Arena Usage API](https://apis.io/apis/arena-predictions-com/arena-predictions-com-usage-api/)

## Tags

Trading

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/arena-predictions-com/arena-predictions-com-trading-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/arena-predictions-com/.