Use Polymarket as an odds layer, not the data source
Polymarket can be useful when a macro event has a public market price but messy market wording. FXMacroData is the normalization layer: it tells you the official institution, event date, indicator, prior value, actual value, and source link. The workflow is to read Polymarket odds, map the market to the right macro event, and verify the outcome with FXMacroData and the official release.
Polymarket describes itself as a prediction-market platform where users trade shares on real-world event outcomes. For macro research, that means Polymarket prices can be treated as a crowd-priced probability input. They should not be treated as the source of record for a policy-rate decision or economic release.
FXMacroData official event -> Polymarket market title and rules -> probability snapshot -> central-bank release -> normalized actual value and post-event comparison.
Step 1: Normalize the market title
Prediction-market titles are written for users, not data pipelines. A title such as "Bank of Brazil Decision in March?" needs normalization before it belongs in a macro workflow. The official event is the Copom policy-rate decision by Banco Central do Brasil, and the measured value is the Selic target rate.
Use FXMacroData to convert the page title into structured fields:
| Market wording | Normalized field | FXMacroData source |
|---|---|---|
| Bank of Brazil | Banco Central do Brasil / Copom | Central-bank press release page and BRL event metadata. |
| Decision in March | Specific Copom meeting and announcement timestamp | Release calendar. |
| Decrease | Actual policy-rate change below prior value | Brazil policy-rate endpoint. |
Step 2: Snapshot odds with context
When you log a Polymarket price, store the probability with the event record, not as the event result. A useful snapshot includes the market URL, timestamp, price, displayed volume/liquidity context, and the exact FXMacroData event it maps to. This lets you compare market-implied probability with the actual result after the announcement.
Polymarket documentation also includes geoblocking guidance for order placement. Keep that separate from the data workflow. Reading a public market page, building a research dashboard, and placing orders are different operational surfaces.
Step 3: Resolve against the official source
For the March 2026 Brazil rate decision, the official Banco Central do Brasil statement reported a Selic target of 14.75% p.a. The prior target was 15.00%, so the normalized result was a 25 basis point cut. The Polymarket outcome can be compared with that result, but the official source remains the central-bank release.
Step 4: Build a repeatable comparison table
For each matched market, keep one row with these fields:
platform: Polymarket.market_url: the Polymarket event page.fxmd_event: currency, indicator, event date, and source agency.pre_event_probability: the market-implied probability at your chosen timestamp.actual_value: the FXMacroData actual value after release.resolution_source: the official central-bank or statistical-agency release.
That table is what makes Polymarket useful for macro research. Without the FXMacroData event mapping, the price is just a page-level observation. With the mapping, it becomes an auditable sentiment input tied to a real macro event.
What Polymarket contributes, in one paragraph
Polymarket contributes public event odds. FXMacroData contributes event identity, timing, historical values, actual values, and source-linked verification. Use Polymarket to understand how a crowd prices the event before release. Use FXMacroData to decide exactly which event it is and what happened.
