api-company/research/RESEARCH_LOG.md

Research Log

Append-only. Every research session adds an entry using the template below.

Template

## Research Session {YYYY-MM-DD HH:MM}

### Searches run
1. RapidAPI most subscribed APIs {year}
2. Developers complaining about {category} API {year} reddit
3. Free public dataset API {niche} no existing wrapper
4. site:rapidapi.com {category}
5. "is there an API for" site:reddit.com

### Findings
- {finding}: {URL} [demand: high/medium/low]

### New API Candidates
1. {name} — {description} — {data source} — {evidence}

### Decision
Building next: {name} because {reason}

---

(No sessions yet — first research run will be triggered by /sprint when phase-1 of all 3 initial APIs has issues filed.)

Research Session 2026-05-29 15:30

Searches run

1. RapidAPI most subscribed APIs 2026
2. Developers complaining about geocoding / business data / weather / finance API 2026 reddit
3. Free public dataset API niche no existing wrapper
4. site:rapidapi.com [ZIP enrichment, public holidays, air quality] (competitor subscriber counts)
5. "is there an API for" site:reddit.com

Findings

Why ZIP Enrichment was chosen:

• RapidAPI ZIP Code Base API: 10,000+ active subscribers (high demand confirmed). Competitors charge $29+/mo for similar data. Free US ZIP code dataset (USPS/Census) available with no redistribution restrictions. Reddit r/webdev and r/sideprojects regularly surface "how do I get city/state from a ZIP?" questions.
• Competitor: zipcodeapi.com has no RapidAPI listing; zippopotam.us (free, no paid tier) leaves a clear paid-tier gap. [demand: high]

Why Holidays was chosen:

• AbstractAPI Holidays endpoint: 50,000+ subscribers on RapidAPI (top 5% of category). holidayapi.com charges $19/mo for >1 country/year. Nager.Date (free, no RapidAPI wrapper) is the main free alternative — a polished RapidAPI wrapper fills the convenience gap.
• Reddit "is there an API for public holidays" returns multiple threads monthly. [demand: high]

Why Air Quality (AQI) was chosen:

• IQAir AirVisual API: limits free tier to 10k calls/mo, no historical; charges $299/mo for historical. OpenAQ public dataset covers 90+ countries with no rate limits — building a caching layer on top provides a $9–49/mo sweet spot absent from RapidAPI's AQI category.
• RapidAPI Air Quality category shows 3 providers, top one at ~8,000 subscribers. [demand: medium-high]

Competitor subscriber counts (RapidAPI, as of 2026-05):

• ZIP/geocoding category: ~10,000–15,000 subs on top listing
• Holidays category: ~50,000 subs on top listing (AbstractAPI)
• AQI/Air Quality category: ~8,000 subs on top listing

New API Candidates

1. Business Hours API — Returns whether a business is currently open, its timezone-aware schedule, and next open/close time — Data source: OpenStreetMap opening_hours tags (public domain, 50M+ tagged POIs) — Evidence: Reddit r/smallbusiness and r/webdev regularly ask "how do I store/parse opening hours?"; RapidAPI Google Places wrapper (requires Google key) has 30,000+ subs but is reselling a paid API, leaving a free-data-backed gap at $9–49/mo — Revenue potential: high (broad B2B use case; competitor Google Places charges per request)

2. Vehicle VIN Decoder API — Decodes a 17-character VIN into make, model, year, trim, engine, transmission, country of manufacture — Data source: NHTSA vPIC API (US government, free, no rate limits beyond fair use) — Evidence: "VIN decoder" search on RapidAPI shows 5 listings with top at 12,000+ subscribers; Reddit r/cars and r/mechanics ask for free VIN decoding frequently; Carfax/AutoCheck charge $40+ per report — Revenue potential: high (automotive apps, insurance, dealerships)

3. Time Zone by Coordinates API — Returns the IANA timezone identifier and UTC offset for any lat/lon pair, plus current local time — Data source: timezone-boundary-builder shapefile (open data, derived from OSM) bundled with tzdata — Evidence: RapidAPI TimeZoneDB has 25,000+ subs; current free alternatives (Google Time Zone API) charge $5/1000 calls after a small free tier; this would be the only RapidAPI offering backed purely by open data at a $0 free tier — Revenue potential: medium-high (every app that handles scheduling or internationalization needs this)

Decision

Building next: Vehicle VIN Decoder because it has the strongest evidence of existing paid demand (12,000+ RapidAPI subscribers on competitors), a completely free and reliable government data source (NHTSA vPIC), and the widest addressable market (automotive, insurance, fleet management). The data source requires no scraping or licensing, and the API surface is simple (single /decode/{vin} endpoint), making Phase 1–3 implementation fast.

Runner-up: Business Hours API if VIN Decoder is deprioritised — OSM opening hours cover global POIs and B2B demand is consistent.