Developer notebook

Prediction Market APIs: A Read-Only Research Workflow

Build a research dataset you can explain: preserve contract rules, distinguish prices, track timestamps, and make missing data visible.

Prediction Market APIs: A Read-Only Research Workflow — original neon typography artwork for PredictionPodcast.com

A prediction market API can turn scattered market pages into a structured research notebook. It can help you track questions, compare observations over time, and prepare an evidence-based podcast discussion. The difficult part is deciding exactly what each observation means. A number without its contract, timestamp, and price definition is easy to misinterpret.

Start with a small read-only project: collect a few public market observations, preserve the rules that give them meaning, and produce a report that another person can reproduce. This guide proposes a workflow for that project. Our prediction market API hub provides the surrounding developer context. No order submission, account funding, or automated execution is required for the research exercise.

Define the research question before collecting data

Write one sentence describing what you want to learn. For example: how did the displayed spread change around a scheduled announcement? That is more precise than collecting every available market and looking for interesting patterns later. Specify the observation window, sampling interval, market inclusion rules, and metrics before the first collection run.

Separate the event you care about from the contract that represents it. A headline may describe an election, product release, or economic announcement broadly, while an individual contract specifies a particular threshold and deadline. Two similar titles can resolve differently. Save the full question, outcome labels, resolution wording, and relevant dates alongside the identifier.

Also decide what would invalidate the study. A rule change, missing announcement timestamp, or extended data outage might make the proposed comparison unreliable. Recording those conditions in advance gives you a consistent way to handle inconvenient observations.

Map the platform's data model

The current Polymarket market-data documentation distinguishes events, markets, and outcomes. An event groups one or more markets, and an outcome has its own token identifier for retrieving its price or order book. This illustrates why a human-readable title is insufficient as a database key. Follow the provider's documented identifiers and relationships.

Create a small market directory before collecting observations. Give each provider its own namespace so identical-looking identifiers cannot collide. Retain the original identifier as text, including leading characters or zeros. Keep your own stable internal key separate from provider fields, and store the outcome label with every observation.

When combining providers, build a deliberate mapping table. Match the resolution condition, deadline, units, and outcome definition. A shared topic does not establish equivalent contracts. Record uncertain matches as uncertain, and leave them out of direct comparisons until a person has reviewed the rules.

Keep raw observations and normalized records

Save the original response before transforming it, subject to the provider's access and reuse terms. A raw record lets you revisit a parsing decision when a field changes or a result looks surprising. Store the retrieval time, request parameters, response status, and parser version with it. Remove secrets from logs if your wider environment uses authenticated services.

Build a second, normalized layer for analysis. It might contain provider, market identifier, outcome identifier, observation time, price type, price value, available size, market status, and a reference to the original response. Describe every field in a short data dictionary. State whether values are fractions, cents, dollars, contracts, or another unit.

Validate the transformation before increasing collection volume. Reject malformed records explicitly, preserve unknown fields when practical, and separate an absent value from a numerical zero. If a field changes type, pause the affected calculation and surface the problem. Silent conversions can make a broken pipeline appear healthy.

Treat time as part of the observation

Record when your system requested the data and when it received the response. Preserve the provider's own timestamp separately when one is supplied. These times answer different questions: when the underlying observation occurred, when it was published, and when your system learned about it. A later download of historical data is not evidence that your system possessed it earlier.

Use a consistent timezone for storage, typically UTC, and make timezone conversions explicit in the report. Keep sufficient precision for the question you are studying. Minute-level observations may support a broad daily discussion, but they cannot establish the ordering of events that occurred seconds apart.

Define a freshness rule appropriate to the intended use. If the latest successful observation is too old, display its age and mark the series stale. An outage should create an observable gap, with a recorded start and recovery time. Filling every gap with the previous value can imply activity or stability that you never observed.

Label prices before comparing them

A last traded price, best bid, best ask, and calculated midpoint describe different things. Choose the relevant measure and name it in every chart. If you calculate a midpoint, document the formula and the conditions under which it is unavailable. An empty side of an order book should not produce a reassuring-looking average.

Consider a hypothetical observation with a best bid of 0.46 and best ask of 0.50. Their midpoint is 0.48, and the quoted spread is 0.04. Those calculations describe the displayed quotes at that moment. They do not establish that a trade occurred at 0.48 or that an arbitrary order could have executed at that price.

Available size matters as well. A price supported by a small visible quantity has a different practical interpretation from the same price with greater depth. For the underlying concepts, read our guide to prediction market liquidity and spreads. Keep descriptive analysis separate from claims about execution quality.

Make collection failures visible

Begin with a modest request schedule that follows the provider's current limits. Cache slowly changing metadata, use documented pagination, and avoid repeatedly requesting the same historical interval. A successful first response is only a starting point; verify that subsequent pages produce new records and that the collection reaches its intended endpoint.

Use bounded retries for temporary failures, with increasing delays where appropriate. Record each failed attempt and stop after a defined limit. A permanently invalid identifier should not trigger an endless retry loop. If the provider supplies a delay instruction, respect it. Collection reliability should come from predictable behavior.

Streaming adds another failure mode: a connection can disconnect while the application still appears active. Track connection health, reconnect according to documented behavior, and restore a consistent snapshot when needed. Preserve sequence information if the provider exposes it. Never assume the absence of a message proves that the market did not change.

Build a report someone else can inspect

A useful research output includes the question, included markets, collection window, metric definitions, missing observations, and known limitations. Report how many records were attempted, collected, excluded, and analyzed. A chart should state the outcome, price measure, timezone, and sampling interval directly in its caption.

For a hypothetical announcement study, preserve a preselected window on either side of the announcement. Compare the recorded spreads and depths, then inspect data coverage in both periods. If collection failed during the most active interval, describe that gap before drawing a conclusion. A later price movement alone does not prove which piece of information caused it.

Keep the selection process reproducible. Save the market directory, transformation version, and analysis settings with the report. For a historical study, include closed and resolved markets according to your predefined rules rather than selecting only the markets still prominent today. Document any exclusions introduced after inspection.

Finish with a small, dependable workflow

A first project is complete when you can trace a chart point back to a source observation, explain its timestamp, and reproduce its calculation. Add more markets only after those checks work. Increasing coverage before establishing clear definitions usually multiplies ambiguity.

The same records can support editorial preparation for a prediction podcast: what changed, when it changed, how complete the evidence is, and which interpretation remains uncertain. A dependable read-only workflow gives you those answers while keeping the underlying observations available for review.

Written for educational use. Examples are hypothetical unless stated otherwise. Sources, revisions, and archive dates.