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Arena Predictions is paper trading for prediction markets at live prices. The HTTP API gives a bearer key read access to Arena-owned data: the key’s own identity and account, public leaderboards and trader records, and Arena’s instruments and games. No real money moves.
There is one environment and no sandbox: every account is a paper account.

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Get started

Making your first request

Call /status, then /me with a key.

API keys

Create, rotate and revoke arena_sk_ keys.

Authentication

Bearer header and scopes.

API reference

Every endpoint, with an interactive playground.

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Reference

Conventions

Names, units, times, identifiers and headers.

Rate limits

Plans, quotas and rate headers.

Errors

The error envelope and every code.

Kalshi mapping

Arena paths next to Kalshi’s.

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Specifications

OpenAPI 3.1

openapi.json, the source for the API reference.

llms.txt

Short version for language models.