One clear API across sources and time.

Use Python or TypeScript to read historical and live public data with the same field names, clear timestamps, and the source attached to every row.

Get API key Read the SDK docs

$29 a month · unlimited fetching · Python 3.11+ and Node 20+

archive-and-live.py

1from mostlyright import weather
2
3live = await weather.live.latest("KNYC")
4history = weather.observations(
5    "KNYC", "2025-01-15", "2025-01-15",
6    return_type="list",
7)[-1]

1import { weather } from "mostlyright";
2
3const live = await weather.latest("KNYC");
4const { rows } = await weather.observations(
5  "KNYC", "2025-01-15", "2025-01-15"
6);
7const history = rows.at(-1);

Use the same fields from archive to live.

Functions name the data they return. Columns name the measurement and unit. Historical, live, and provider-specific records preserve documented field meanings.

One contract for historical and live data.

Train on historical rows, then read live reports without renaming shared measurements or rebuilding parsers.

Use only data available at the time.

Keep event time separate from publication time, preserve revisions, and filter against a research cutoff.

Know where every row came from.

Every row names its source. Deterministic merge rules handle overlapping feeds without silently averaging them.

Use maintained source definitions without sending every request through us.

Your API key retrieves the latest endpoint, schema, and source definitions. The SDK then fetches supported data directly from its public source and keeps a local provenance record.

How source resolution works →

quickstart.py

export MOSTLYRIGHT_API_KEY="mr_live_..."

from mostlyright import weather

rows = weather.observations(
    "KNYC", "2025-01-15", "2025-01-15"
)

From weather stations to financial reports.

Install one package for the common API, or depend only on the domain packages your application uses.

Weather

Live observations, archives, forecasts, daily summaries, hazards, satellite measurements, and river gauges.

Prediction markets

Kalshi and Polymarket discovery, history, order books, settlement data, and weather-contract resolvers.

Economy

CPI, PPI, payrolls, GDP, jobless claims, and Fed decisions with first-publication vintages.

Finance

Earnings-call transcripts and company mentions with publication and spoken times kept explicit.

Install the whole SDK in one command.

Python and TypeScript follow the same naming and source conventions, with generated reference documentation for every public module and export.

install

# Python
pip install mostlyrightmd

# TypeScript
pnpm add mostlyright

Fetch your first rows.

Install the SDK, add your API key, and fetch historical or live data in a few lines of code.

Get API key