Method

Sources, provenance, and what this analysis cannot know

Every figure on this site is computed by a script from a committed dataset. Nothing is typed in by hand. This page is generated from the provenance ledger the fetchers write, so it cannot drift from what the pipeline actually pulled.

Datasets

Dataset	Publisher	Coverage	Rows	Terms
`amfi_fund_houses`	Association of Mutual Funds in India (AMFI)	20-Aug-2026	52	AMFI terms; publicly published daily NAV file
`amfi_schemes`	Association of Mutual Funds in India (AMFI)	20-Aug-2026	14,288	AMFI terms; publicly published daily NAV file
`bank_fundamentals`	Yahoo Finance	11 NSE tickers	47	Yahoo Finance terms; personal/research use
`bank_prices`	Yahoo Finance	11 NSE tickers	13,580	Yahoo Finance terms; personal/research use
`india_rates`	FRED (Federal Reserve Bank of St. Louis), series sourced from OECD / RBI	1968-01 to 2026-06	702	FRED terms of use; underlying series (c) OECD. Free to redistribute with attribution.
`pulse_base_national`	PhonePe Pulse	2018Q1 to 2026Q2	34	CDLA-Permissive-2.0 (see PhonePe/pulse repository LICENSE)
`pulse_txn_national`	PhonePe Pulse	2018Q1 to 2026Q2	102	CDLA-Permissive-2.0 (see PhonePe/pulse repository LICENSE)
`pulse_txn_state`	PhonePe Pulse	2018Q1 to 2026Q2	1,224	CDLA-Permissive-2.0 (see PhonePe/pulse repository LICENSE)
`pulse_txn_state_mix`	PhonePe Pulse	2026Q2	108	CDLA-Permissive-2.0 (see PhonePe/pulse repository LICENSE)
`upi_apps`	NPCI (UPI Ecosystem Statistics)	2023-12 to 2026-07	132	NPCI terms apply to the underlying data
`upi_apps_hhi`	NPCI (UPI Ecosystem Statistics)	2023-12 to 2026-07	12	NPCI terms apply to the underlying data
`upi_monthly`	NPCI via India Data Portal (CKAN mirror)	2016-07 to 2026-07	116	NPCI terms apply to the underlying data
`worldbank_india`	World Bank Open Data	1960 to 2025	66	CC BY 4.0

All accessed 2026-08-21. Code in this repository is Apache 2.0 licensed; each dataset retains its publisher's own terms.

Caveats carried into every exhibit

amfi_fund_houses, Scheme universe snapshot; scheme counts are not AUM.
amfi_schemes, Scheme universe snapshot; scheme counts are not AUM.
bank_fundamentals, Retrieved via the yfinance library. NIM here is a PROXY: net interest income / average total assets, not reported NIM.
bank_prices, Retrieved via the yfinance library. NIM here is a PROXY: net interest income / average total assets, not reported NIM.
india_rates, India immediate/call money interbank rate, monthly. Fetched from FRED's keyless CSV endpoint so the pipeline needs no credentials. Months FRED does not publish are dropped, never interpolated.
pulse_base_national, Registered users and registered merchants. PhonePe's own transactions, not all of UPI.
pulse_txn_national, P2P / Retail (merchant) / Utility split. PhonePe's own transactions, not all of UPI.
pulse_txn_state, State-level transaction count and value. PhonePe's own transactions, not all of UPI.
pulse_txn_state_mix, P2P / merchant / utility split within each state, from the per-state aggregated endpoint. Reconciled against the country file. PhonePe's own transactions, not all of UPI.
upi_apps, Top ten apps by volume, transcribed from a browser session because NPCI returns HTTP 403 to scripted access. Shares are computed against the NPCI national monthly total, so they are true market shares and the residual is real.
upi_apps_hhi, Top ten apps by volume, transcribed from a browser session because NPCI returns HTTP 403 to scripted access. Shares are computed against the NPCI national monthly total, so they are true market shares and the residual is real.
upi_monthly, CKAN mirror STOPS AT 2023-08. Rows after that are hand-seeded from npci.org.in, which returns HTTP 403 to scripted access. The `provenance` column marks which is which.
worldbank_india, Indicators: FX.OWN.TOTL.ZS, FX.OWN.TOTL.FE.ZS, NY.GDP.MKTP.CD, SP.POP.TOTL, SP.POP.0014.TO, FB.AST.NPER.ZS, FS.AST.PRVT.GD.ZS

What was deliberately not used

RBI DBIE (data.rbi.org.in): An Angular application with no documented public REST API. Net interest margin is derived from filed income statements instead, which is more defensible than screen-scraping a portal.
NPCI direct scraping: npci.org.in returns HTTP 403 to every scripted request. Recent months are transcribed from a browser session with per-row provenance instead. The overlap month matches the open mirror exactly, confirming no level shift at the seam.
data.gov.in: The public sandbox key authenticates, but filtered resource queries time out and many finance resources have no active API. It would add nothing the spine does not already cover.
Perspective, Superset, Panel, Redash, Vizro, glue: Each needs a live Python or Node backend, which a static free-hosted site cannot have, or ships several megabytes of WASM to pivot 36 rows. The workbench is built in code instead, which keeps the page fast.
D3: Dropped after the charts were specified. A four-point cohort chart is server-rendered SVG with no JavaScript at all, and ECharts covers the rest. Removing it took a dependency and a client bundle out of the project.
WebGPU: No dataset here is remotely large enough to justify it.

Three rules the pipeline enforces

Never fabricate a number. If a value was not fetched or computed it stays a visible gap. Four months NPCI does not publish are left empty rather than interpolated.
Fail loud on shape change. Each fetcher validates its schema and range. The bank fetcher refused to run when a NIM came back negative, correctly, because the company was a payments firm, not a bank.
Synthetic data announces itself. The survey panel is generated. It says so in the filename, on the chart, and at the top of the memo.