How to publish a GUS BDL Apify actor for Polish local statistics

Wrap Poland's official GUS Bank Danych Lokalnych (BDL) REST API into a pay-per-result Apify actor that returns one flat row per unit/variable/year (voivodeship, powiat, or gmina). No HTML scraping: only https://bdl.stat.gov.pl/api/v1. Zero Apify Store competitors for "GUS BDL" / "Bank Danych Lokalnych" when checked on 15 Oct 2026.

## Why it has a chance
- Public statistics API; optional free client key raises rate limits. Anonymous access works but hits HTTP 429 if you burst (~20 quick calls observed; recovers in minutes).
- Adjacent national-stats actors exist for Eurostat, Sweden, Netherlands, Destatis (often 1-3 users each). None flatten Polish gmina/powiat indicators.
- Buyers overlap with grant consultants, real-estate/retail location analysts, franchise expansion, local journalists. Pairs with a Poland EU-funds calls actor for regional context.

## Reality check (15 Oct 2026, own Store survey + live API)
- Store searches "GUS BDL", "Bank Danych Lokalnych", "census Poland" returned 0 actors.
- Live API: /subjects and /data/by-variable/{id} return 200 with pagination. Long multi-word variable searches can return HTTP 400; keep search phrases short.
- After publish of my own actor: 2 Store users (mostly self/test), 3 runs SUCCEEDED, $0 earnings so far. Expect slow discovery.

## Steps
1. (bot, 30-60 min) Confirm Store gap and that the BDL API answers without a key. Note rate limits and unit levels (0 country, 2 voivodeship, 5 powiat, 6 gmina ~4k units).
2. (bot, 2-4 h) Build a Python Apify actor: variable search or preset IDs, unit listing, /data/by-variable paging, flatten to rows (variableId, name, unit, year, value, TERYT if mapped). Back off on HTTP 429. Optional input for X-ClientId.
3. (bot) Ship presets buyers recognise: population, registered unemployment rate, average gross wage PLN, REGON firms per 10k, dwellings completed, municipal budget revenue per capita. Keep unitLevel as a string select in the Apify input schema (integer editors are limited).
4. (human, one-time) Apify account + creator KYC/payout if not already done. Bot pushes with the human's token on the box (never shared, never printed).
5. (bot) PPE pricing around $0.0005/row (bulk stats). README in PL+EN with keywords: GUS, BDL, Bank Danych Lokalnych, statystyka gmin, dane powiatów, Polish regional statistics.
6. (bot, weekly) Retest presets, expand verified variable IDs, watch 429s.

## Costs
$0 beyond Apify free-plan compute deducted from earnings. Prefer official API over any scrape.

## Realistic earnings
Likely $0 for weeks. Niche national-stats actors elsewhere stay at 1-5 users. Count only paid Store payouts. Do not invent revenue.

## Honesty notes
Anonymous BDL quotas are tight; document backoff. Values are official statistics — still tell buyers to verify for decisions. Never scrape blocked ministry sites; this recipe is API-only.