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name: tam-sam-som-builder description: Estimates TAM, SAM, and realistic SOM for a B2C app idea using triangulated bottom-up methodology anchored to market_insights trend data, competitor revenue proxies, and community size signals. Includes indie capture rate benchmarks and growth-rate adjustments by trend velocity.

Skill: tam-sam-som-builder

Purpose

Provide a realistic market size estimate that an indie developer can actually use for decisions. Most TAM estimates are useless because they use top-down analyst numbers designed to impress VCs, not to inform a solo builder deciding where to spend the next 6 months. This skill uses triangulated bottom-up methodology — multiple independent estimation approaches cross-checked against each other — anchored to real signals from market_insights/ trend data.

Input

• Idea slug (or market research slug for pre-idea deep dives)
• memory/ideas/<slug>/keywords.json (search volume estimates — if available)
• memory/ideas/<slug>/competitors.json (competitor scale and pricing signals)
• memory/ideas/<slug>/pricing.json (target price — if available)
• memory/market_insights/<niche>-*-<YYYY>-<MM>.md (trend analysis files — use all available platform files for this niche)

Using Market Insights

Trend analysis files from memory/market_insights/ provide critical calibration data. Extract the following from each available file's YAML frontmatter and narrative:

Field	How it informs TAM/SAM/SOM
trend_velocity	Adjusts growth rate projections (see Step 5)
top_signals	Validates that real demand exists; calibrates bottom-up search volume estimates
monetization_evidence	Confirms WTP — if no monetization evidence exists across any platform, discount TAM by 30–50%
overall_verdict (hot/warm/cool/cold)	Sanity-check on whether the market is worth sizing at all
Platform narrative (Reddit pain points, TikTok engagement, App Store reviews)	Source for community size proxy estimation (see Approach B)

If overall_verdict across platforms is "cold", flag the entire estimate as speculative and note that market demand is unvalidated.

Methodology

Approach A — Search Volume (primary when keywords.json available)

TAM = monthly_search_volume × 12 × intent_conversion_rate × annual_price

Where:

• monthly_search_volume = total from keywords.json across all relevant keywords
• intent_conversion_rate = % of searchers who have genuine purchase intent (see benchmarks below)
• annual_price = from pricing.json target WTP, annualized

Intent conversion benchmarks by search type:

Search intent	Conversion rate	Example query
Direct solution search ("app to track X")	8–15%	"habit tracker app", "budget planner iOS"
Problem-aware search ("how to X")	3–8%	"how to save money", "how to build habits"
Category browsing ("best X apps")	5–12%	"best workout apps 2026", "top meditation apps"
Tangential interest ("X tips")	1–3%	"productivity tips", "healthy eating advice"

Approach B — Community Size Proxy (primary when market_insights available)

When keyword data is weak but trend analysis reveals active communities, estimate from community engagement:

TAM = active_community_members × platform_multiplier × annual_price

Where:

• active_community_members = sum of engaged users across platforms (subreddit subscribers, TikTok hashtag creators, App Store review volume)
• platform_multiplier = ratio of total interested population to active community members (see below)

Platform multipliers (how many silent interested people per active community member):

Signal source	Multiplier	Rationale
Reddit subscribers in niche subreddit	20–50×	~2–5% of interested people join a subreddit
TikTok hashtag creators (not views)	100–500×	Tiny fraction of interested people create content
App Store reviews for top competitor	50–100×	~1–2% of users leave reviews
Newsletter subscribers in niche	10–30×	Email subscribers are a warmer proxy

Approach C — Competitor Revenue Proxy (supplementary)

Estimate from competitor data in competitors.json:

TAM = sum of estimated annual revenue across all mapped competitors × market_coverage_factor

Where:

• Estimate competitor revenue from: estimated_users × competitor_price × 12 × estimated_conversion_rate
• market_coverage_factor = 1.3–2.0× (competitors don't capture the full market). Use 1.3× for saturated markets, 2.0× for markets with few competitors.

Triangulation

Run all available approaches and compare:

• If estimates agree within 2× → high confidence. Use the geometric mean.
• If estimates disagree by 2–5× → medium confidence. Use the most conservative estimate and note the range.
• If estimates disagree by > 5× → low confidence. Flag assumptions that cause the divergence.

Always report which approaches were used and their individual estimates in the output.

SAM Filtering

SAM narrows TAM to the segment actually reachable by the app. Apply these filters in order:

Geographic & Platform Filters

Filter	How to apply	Data source
Platform	iOS-only → multiply TAM by iOS market share in target geography	See benchmarks below
Geography	English-only → US + UK + CA + AU + NZ + IE. Specific country → that country only	App concept language
Age range	If app targets a demographic (teens, 50+), apply population %	Idea description
Income bracket	If app requires disposable income for subscription, filter by income	Pricing model

iOS market share by region (for iOS-only apps):

Region	iOS share (approximate)
United States	55–58%
United Kingdom	50–53%
Canada	53–56%
Australia	55–58%
Western Europe (avg)	30–35%
Global	25–28%
Southeast Asia	10–15%
India	4–6%
Latin America	12–18%

For Android-only or cross-platform, apply the inverse or use 100%.

Segment Filters

Beyond geography and platform, apply any filters that narrow the market to people who would actually consider this specific app:

• Niche focus (e.g., "fitness" → "climbing-specific fitness")
• Prerequisite behavior (e.g., "already tracks workouts" → subset of fitness app users)
• Tech-savviness requirement (if the app requires unusual setup, filter out casual users)

SAM should typically be 10–40% of TAM. If SAM > 50% of TAM, the filters are too loose. If SAM < 5% of TAM, the niche may be too narrow for viable economics.

SOM Estimation

SOM is what an indie developer can realistically capture. This is where most estimates go wrong — indie builders don't have the resources to capture meaningful market share in crowded categories.

SOM Capture Rate Benchmarks by Category

App category	Year 1 capture rate	Year 3 capture rate	Notes
Utility / tool (calculator, converter, scanner)	0.1–0.5% of SAM	0.5–2.0%	Discoverable via ASO, many competitors
Niche productivity (specific workflow tool)	0.5–2.0%	2.0–5.0%	Smaller SAM but higher capture in the niche
Health & fitness (niche)	0.3–1.5%	1.0–4.0%	Loyal users if retention is strong
Health & fitness (broad)	0.05–0.2%	0.2–0.8%	Dominated by incumbents
Social / community	0.01–0.1%	0.1–0.5%	Network effects favor incumbents; cold start is brutal
Content / media	0.1–0.5%	0.5–2.0%	Depends heavily on content quality and curation
Finance / budgeting	0.1–0.5%	0.5–2.0%	High trust barrier, but sticky once adopted
Creative tools (photo, video, design)	0.2–1.0%	1.0–3.0%	Shareable output drives organic growth
Education / learning	0.2–1.0%	1.0–3.0%	Retention is the main challenge
Lifestyle / habit	0.3–1.5%	1.0–4.0%	Success varies wildly by habit loop quality

Use the lower end of the range when:

• market_saturation from competitors.json is "high"
• Founder is beginner tier (from user_profile.md)
• No distribution advantage identified

Use the upper end when:

• Founder has an existing audience or distribution edge
• Strong ASO opportunity or viral loop exists
• Market is growing fast (trend_velocity = "rising-fast")

SOM Calculation

SOM_year_1 = SAM × capture_rate_year_1
SOM_year_3 = SAM × capture_rate_year_3 × growth_multiplier

Growth Rate Adjustment (from market_insights)

Trend velocity from market_insights directly affects the year-3 projection:

Trend velocity	Growth multiplier (applied to year-3 SOM)	Rationale
rising-fast	1.5–2.0×	Market is expanding — your share of a growing pie grows faster
rising	1.2–1.5×	Moderate tailwind
stable	1.0×	No adjustment — capture rate is the only growth driver
declining	0.5–0.8×	Shrinking market — your absolute numbers may drop even if capture rate improves

If multiple platform files have different velocities, use the median velocity.

Reality Check Layer

Before finalizing, run these sanity checks:

Check	Threshold	Action if triggered
TAM inflation	TAM > $10B for a niche indie app	Almost certainly using top-down numbers. Redo with bottom-up only.
SAM too broad	SAM > 50% of TAM	Filters are too loose. Add platform/geography/niche constraints.
SOM fantasy	SOM year 1 > $500K for a solo developer	Reality-check the capture rate. Most indie apps earn $0–$50K in year 1.
No monetization evidence	monetization_evidence from market_insights is empty across all platforms	Discount TAM by 30–50%. People may want this but not pay for it.
Cold market	All market_insights files show overall_verdict = "cold" or "cool"	Flag as speculative. Note that market demand is unvalidated.

Market Size Verdict Thresholds

Based on SOM year 1 (the number that actually matters for an indie developer deciding whether to build):

SOM year 1	Verdict	Meaning for an indie dev
> $200K	large	Significant indie opportunity. Even partial execution could be life-changing.
$50K–$200K	medium	Viable as a primary project. Can sustain a solo developer if retention is good.
$10K–$50K	niche	Side-project scale. Viable if build cost is low and the founder has another income source.
< $10K	micro-niche	Hobby scale. Only worth building if the founder has a personal reason to build it or can expand the niche.

Process

1. Load all available inputs: keywords.json, competitors.json, pricing.json, and all matching memory/market_insights/<niche>-*-<YYYY>-<MM>.md files.
2. Extract calibration data from market_insights (trend velocity, top signals, monetization evidence, overall verdict).
3. Run Approach A (search volume) if keywords.json is available.
4. Run Approach B (community size proxy) if market_insights contain community signals.
5. Run Approach C (competitor revenue proxy) if competitors.json has user/pricing data.
6. Triangulate: compare estimates, determine confidence, select final TAM.
7. Apply SAM filters (geography, platform, demographics, niche).
8. Estimate SOM using category-appropriate capture rate benchmark.
9. Apply growth multiplier from trend velocity.
10. Run reality checks. Adjust if any are triggered.
11. Determine market size verdict from SOM year 1 thresholds.
12. Write output.

Output

Write to memory/ideas/<slug>/market_size.json:

{
  "methodology": "bottom-up | community-proxy | competitor-proxy | triangulated",
  "estimation_approaches": [
    {
      "approach": "search-volume | community-proxy | competitor-proxy",
      "tam_estimate": 0,
      "key_assumptions": []
    }
  ],
  "triangulation_confidence": "high | medium | low",
  "tam": {
    "value": 0,
    "currency": "USD",
    "period": "annual",
    "assumptions": []
  },
  "sam": {
    "value": 0,
    "filter_criteria": [],
    "sam_to_tam_ratio": 0
  },
  "som": {
    "year_1": 0,
    "year_3": 0,
    "capture_rate_year_1_pct": 0,
    "capture_rate_year_3_pct": 0,
    "growth_multiplier": 1.0,
    "growth_multiplier_source": ""
  },
  "market_insights_used": [],
  "trend_velocity_observed": "rising-fast | rising | stable | declining",
  "monetization_evidence_found": true,
  "reality_checks_triggered": [],
  "market_size_verdict": "large | medium | niche | micro-niche"
}

Notes

• When used in the market-deep-dive workflow, pricing.json may not exist yet. In that case, use the median competitive price from competitors.json or a category benchmark ($3–$7/mo for typical B2C subscription apps).
• When used in idea-validation (if the orchestrator includes it), the output feeds into idea-scoring's Monetization dimension. The market_size_verdict and SOM values are used alongside pricing and CAC data to assess overall monetization viability.
• Market_insights files have a stale_after date. If all available files are past their stale date, flag the estimates as potentially outdated and recommend re-running trend-analysis before making a build decision.