Support & Resistance
Support and resistance are price zones where buying or selling pressure has historically been strong enough to reverse or stall a price move. These zones are among the most fundamental concepts in technical analysis — nearly every trading strategy references them in some way. Engulfy automatically detects these zones and alerts you when price interacts with them.
Support and resistance zones diagram — showing price bouncing off support below and being rejected at resistance above
What Is Support?
A support level is a price zone below the current price where buying interest has historically been strong enough to prevent the price from falling further. Think of it as a "floor" — when the price drops to this level, buyers step in because they perceive the price as attractive.
Support levels are formed when the price drops to a zone, buyers overwhelm sellers, and the price bounces back up. The more times this happens at the same zone, the more significant that support level becomes — it means there is persistent buying demand at that price range.
What Is Resistance?
A resistance level is a price zone above the current price where selling pressure has historically been strong enough to prevent the price from rising further. Think of it as a "ceiling" — when the price rises to this level, sellers step in because they perceive the price as expensive or take profits on existing positions.
Like support, resistance levels become more significant with more "touches" — each time the price reaches the zone and falls back, it reinforces the level's importance.
Why Do Support and Resistance Work?
Support and resistance aren't magical lines. They work because of human psychology and market memory:
- Anchoring bias — traders remember prices where they bought or sold before, and tend to act at those same levels again.
- Institutional orders — large funds often place buy/sell orders at round numbers or historically significant prices, creating visible demand/supply zones.
- Self-fulfilling prophecy — because many traders watch the same levels, they all tend to act at the same time, reinforcing the zone's effect.
- Pain and regret — traders who missed a bounce at support may place buy orders "next time it comes back," creating future demand at that level.
Zones, Not Exact Lines
An important distinction: support and resistance are better understood as zones rather than exact price lines. Price rarely reverses at exactly the same penny twice. Instead, it tends to react within a narrow range — sometimes slightly above, sometimes slightly below the previous turning point.
Engulfy reflects this by detecting S/R as zones with a low, center, and high bound rather than single price points. A support zone at $50 might span from $49.60 to $50.40, with the center at $50.00.
Types of S/R Interactions
When price approaches a support or resistance zone, several things can happen. Engulfy detects eight specific interaction types:
| Signal | What It Means | Strength |
|---|---|---|
| Broke Resistance | Price closed above the zone with confirmation, signaling a breakout. | High |
| Broke Support | Price closed below the zone with confirmation, signaling a breakdown. | High |
| Rejected at Resistance | Price touched the zone and was pushed back down with a bearish candle and significant drop. | Medium |
| Bounced at Support | Price touched the zone and was pushed back up with a bullish candle and significant rise. | Medium |
| Breached Resistance | Price entered the zone from below for the first time. Not yet confirmed as a breakout. | Moderate |
| Breached Support | Price entered the zone from above for the first time. Not yet confirmed as a breakdown. | Moderate |
| Approaching Resistance | Price is trending up and getting close to a resistance zone. | Low |
| Approaching Support | Price is trending down and getting close to a support zone. | Low |
The signals are evaluated in priority order: Broke > Breached > Rejected/Bounced > Approaching. Only the most significant signal fires for each zone.
Breakouts and Breakdowns
A breakout occurs when the price pushes decisively above a resistance zone. This often signals the start of a new uptrend, because the sellers who had been capping the price have been overwhelmed by buyers. A breakdown is the opposite — price falls below support, suggesting the buyers who had been holding the line have capitulated.
Not all breakouts stick. False breakouts (also called "fakeouts") happen when price briefly pushes above resistance but quickly falls back below. This is why Engulfy requires two consecutive closes above/below the zone before flagging a "Broke" signal — it waits for confirmation rather than triggering on the first touch.
Role Reversal
One of the most powerful concepts in S/R analysis is role reversal: when a resistance level is broken, it often becomes support on the way back down, and vice versa. Traders who missed the breakout may buy on the "retest" of the old resistance (now support), creating demand at that level again.
Example: A stock struggles to break above $50 for months (resistance). Once it finally closes above $50, future pullbacks often find buyers near $50 (now support). The old ceiling becomes the new floor.
What Makes a Zone Strong?
- More touches — a zone tested 5 times is more significant than one tested only twice. Each touch adds evidence that the level matters.
- Longer time span — a support zone that has held for 6 months is more meaningful than one that formed over 2 weeks.
- Volume at the zone — high-volume reactions at a level indicate institutional interest, not just retail traders.
- Higher timeframe — weekly and monthly S/R zones are generally more significant than daily ones.
Engulfy ranks detected zones using a composite score that factors in both the number of touches and the time span over which the zone has been active. Zones with many touches spread over a long period get the highest rank.
How Engulfy Detects the Support & Resistance
- Scans historical OHLCV data for pivot highs (local peaks) and pivot lows (local valleys) using a timeframe-appropriate lookback window.
- Clusters nearby pivots into zones using a calibrated tolerance that accounts for the fact that price rarely reverses at the exact same penny.
- Filters out weak zones by requiring a minimum number of touches with sufficient time separation between them.
- Classifies each zone as support (below current price) or resistance (above current price).
- Evaluates the current bar against each zone to generate one of 8 signal types, in priority order: Broke > Breached > Rejected/Bounced > Approaching.
- Rejection and bounce signals require both a confirming candle body direction and a significant price move within a short window.
- Approaching signals require proximity to the zone and a confirmed trend direction toward it.
Pivot lookback and tolerance parameters are tuned per timeframe. Engulfy uses ATR-based thresholds where available for adaptive sensitivity.
Expert References
- John Murphy, Technical Analysis of the Financial Markets (1999) — provides a comprehensive treatment of S/R as the foundation of chart analysis.
- Al Brooks, Trading Price Action series (2012) — emphasizes that S/R is about "areas of prior agreement on value" and that exact levels matter less than the zone of interest.
- Thomas Bulkowski, Encyclopedia of Chart Patterns (2005) — provides statistical analysis of breakout success rates. His data shows that breakouts from well-established ranges succeed approximately 60-70% of the time when confirmed by volume.
Controversy & Limitations
- Subjective identification: Different traders draw S/R levels differently. Some use closing prices, others use wicks, and the "correct" level is often debatable. Engulfy's algorithmic approach removes this subjectivity by using consistent pivot-detection and clustering rules.
- False breakouts are common: Especially in low-volume or choppy markets, price can briefly pierce a support or resistance zone and then reverse. This is why Engulfy requires two consecutive closes for a "Broke" signal.
- No level holds forever: Every support level eventually breaks under enough selling pressure, and every resistance level eventually gives way to persistent buying. S/R is about probabilities, not certainties.
- Less useful in trending markets: During strong trends, price blasts through support and resistance levels routinely. S/R analysis is most useful in ranging or transitioning markets.