(new): JSON HTML escaping control

- add Formatter.JSONEscapeHTML and SetJSONEscapeHTML to let JSON writers preserve HTML-sensitive characters when needed while keeping escaping enabled by default.
- switch JSON output to json.Encoder, preserve existing Print/Println newline semantics, and cover the new escaping behavior in tests.

README.md

@@ -71,6 +71,10 @@ func main() {
 
 Important: with the current level ordering, `Level(sneklog.FATAL)` allows `INFO`, `WARN`, `ERROR`, and `FATAL`, but not `DEBUG`. Use `Level(sneklog.DEBUG)` to enable every level.
 
+If you want classic threshold filtering instead, call `SetThresholdMode(true)` and
+configure levels with `NewThresholdLogLevel(...)` or
+`NewThresholdLogLevelWithColors(...)`.
+
 ## Writers and ownership
 
 `Logger.Close()` only closes writers created by the logger itself:
@@ -135,6 +139,49 @@ httpCache.SetForeground256Color(214)
 Because `LogLevel` setters mutate the level in place, call them on a variable, not on a temporary value returned by `NewLogLevel(...)`.
 Short forms such as `SetFgColor` and `SetBgColor` remain available for backward compatibility.
 
+Common severities also have dedicated helpers:
+
+```go
+access := sneklog.NewInfoLogLevelWithColors("access", sneklog.FgCyan, sneklog.BgNone)
+audit := sneklog.NewWarnLogLevel("audit")
+```
+
+These helpers keep the legacy severity index for backward compatibility and also
+assign default threshold values:
+
+- `INFO`: `th=10`
+- `WARN`: `th=20`
+- `ERROR`: `th=30`
+- `FATAL`: `th=40`
+- `DEBUG`: `th=0`
+
+To define custom threshold-based levels explicitly:
+
+```go
+trace := sneklog.NewThresholdLogLevelWithColors(4, 5, "trace", sneklog.FgHiBlack, sneklog.BgNone)
+audit := sneklog.NewThresholdLogLevel(1, 25, "audit")
+
+logger := sneklog.NewLogger().
+	SetLevel(audit).
+	SetThresholdMode(true)
+
+logger.Print(trace, "verbose trace") // filtered out
+logger.Print(audit, "audit event")   // allowed
+```
+
+HTTP method-specific predefined levels are available out of the box:
+
+```go
+level := sneklog.LogLevelForMethod(http.MethodPost)
+logger.Print(level, "POST /users")
+```
+
+When comparing levels:
+
+- use `SameLevel` if only the legacy severity index matters;
+- use `SameThreshold` if only threshold filtering matters;
+- use `Equal` if the full configuration, including threshold, colors, and attributes, must match.
+
 ## Message replacement
 
 `AddReplacer(old, new)` replaces matching text in every message before the
@@ -157,6 +204,7 @@ An empty `old` value is ignored.
 
 - `Info`, `Warn`, `Error`, `Debug`, and `Fatal` accept a list of values.
 - `Infof`, `Warnf`, `Errorf`, `Debugf`, and `Fatalf` use `fmt.Sprintf`.
+- `Printf(level, format, args...)` formats a message for an explicit `LogLevel`.
 - The `*ln` methods preserve newline semantics, which is useful for `stdout`, Docker, and line-based collectors.
 - `Fatal`, `Fatalf`, and `Fatalln` call `os.Exit(1)` after writing the message.
 - `AddReplacer` masks or rewrites message text before records are sent to writers.

README_ru.md

@@ -71,6 +71,10 @@ func main() {
 
 Важно: в текущей модели уровней `Level(sneklog.FATAL)` пропускает `INFO`, `WARN`, `ERROR` и `FATAL`, но не `DEBUG`. Чтобы включить все сообщения, используйте `Level(sneklog.DEBUG)`.
 
+Если нужна классическая threshold-фильтрация, включите `SetThresholdMode(true)` и
+задавайте уровни через `NewThresholdLogLevel(...)` или
+`NewThresholdLogLevelWithColors(...)`.
+
 ## Writer'ы и владение
 
 `Logger.Close()` закрывает только writer'ы, которые логгер создал сам:
@@ -135,6 +139,49 @@ httpCache.SetForeground256Color(214)
 Так как setter'ы `LogLevel` изменяют уровень на месте, их нужно вызывать на переменной, а не на временном результате `NewLogLevel(...)`.
 Короткие формы вроде `SetFgColor` и `SetBgColor` сохранены для обратной совместимости.
 
+Для стандартных severity также есть отдельные helper'ы:
+
+```go
+access := sneklog.NewInfoLogLevelWithColors("access", sneklog.FgCyan, sneklog.BgNone)
+audit := sneklog.NewWarnLogLevel("audit")
+```
+
+Эти helper'ы сохраняют legacy severity index для обратной совместимости и
+одновременно выставляют значения threshold по умолчанию:
+
+- `INFO`: `th=10`
+- `WARN`: `th=20`
+- `ERROR`: `th=30`
+- `FATAL`: `th=40`
+- `DEBUG`: `th=0`
+
+Чтобы явно создавать уровни для threshold-режима:
+
+```go
+trace := sneklog.NewThresholdLogLevelWithColors(4, 5, "trace", sneklog.FgHiBlack, sneklog.BgNone)
+audit := sneklog.NewThresholdLogLevel(1, 25, "audit")
+
+logger := sneklog.NewLogger().
+	SetLevel(audit).
+	SetThresholdMode(true)
+
+logger.Print(trace, "verbose trace") // будет отфильтровано
+logger.Print(audit, "audit event")   // будет записано
+```
+
+Для HTTP-методов доступны готовые уровни:
+
+```go
+level := sneklog.LogLevelForMethod(http.MethodPost)
+logger.Print(level, "POST /users")
+```
+
+При сравнении уровней:
+
+- используйте `SameLevel`, если важен только legacy severity index;
+- используйте `SameThreshold`, если важна только threshold-фильтрация;
+- используйте `Equal`, если нужно полное совпадение конфигурации, включая threshold, цвета и атрибуты.
+
 ## Замена сообщений
 
 `AddReplacer(old, new)` заменяет найденный текст в каждом сообщении до того,
@@ -156,6 +203,7 @@ logger.Infoln("login token:", "SOME_SECRET")
 
 - `Info`, `Warn`, `Error`, `Debug`, `Fatal` принимают список значений.
 - `Infof`, `Warnf`, `Errorf`, `Debugf`, `Fatalf` используют `fmt.Sprintf`.
+- `Printf(level, format, args...)` форматирует сообщение для явного `LogLevel`.
 - Методы `*ln` добавляют семантику перевода строки, что удобно для `stdout`, Docker и line-based collectors.
 - `Fatal`, `Fatalf` и `Fatalln` вызывают `os.Exit(1)` после записи сообщения.
 - `AddReplacer` маскирует или переписывает текст сообщений перед отправкой в writer'ы.

RELEASE_NOTES.md

@@ -1,3 +1,86 @@
+# v2.3.0
+
+This release adds JSON HTML-escaping control while preserving the existing
+JSON writer defaults and newline semantics.
+
+### Added
+
+- Added `Formatter.SetJSONEscapeHTML(bool)` and `Formatter.JSONEscapeHTML` to control whether JSON writers escape HTML-sensitive characters such as `<`, `>`, and `&`.
+
+### Changed
+
+- JSON writers now use `json.Encoder` internally so formatter-level HTML escaping can be configured.
+
+### Fixed
+
+- Preserved `Print` and `Println` newline behavior for JSON output while switching to `json.Encoder`.
+
+### Compatibility
+
+- No breaking API changes.
+- HTML escaping remains enabled by default, matching the previous `encoding/json` behavior.
+- `Print` still emits JSON without an added newline, and `Println` emits exactly one trailing newline.
+
+# v2.2.0
+
+This release expands the public LogLevel API, adds optional threshold-based
+filtering alongside the legacy severity ordering, and improves documentation
+and test coverage.
+
+### Added
+
+- Added dedicated log level constructors:
+  - `NewInfoLogLevel`
+  - `NewInfoLogLevelWithColors`
+  - `NewWarnLogLevel`
+  - `NewWarnLogLevelWithColors`
+  - `NewErrorLogLevel`
+  - `NewErrorLogLevelWithColors`
+  - `NewFatalLogLevel`
+  - `NewFatalLogLevelWithColors`
+  - `NewDebugLogLevel`
+  - `NewDebugLogLevelWithColors`
+- Added threshold-aware log level constructors:
+  - `NewThresholdLogLevel`
+  - `NewThresholdLogLevelWithColors`
+- Added HTTP method-specific predefined log levels:
+  - `HTTPGetLevel`
+  - `HTTPHeadLevel`
+  - `HTTPPostLevel`
+  - `HTTPPutLevel`
+  - `HTTPPatchLevel`
+  - `HTTPDeleteLevel`
+  - `HTTPOptionsLevel`
+  - `HTTPConnectLevel`
+  - `HTTPTraceLevel`
+  - `HTTPUnknownLevel`
+- Added `LogLevelForMethod(method string) LogLevel` to map HTTP methods to predefined log levels.
+- Added `Logger.Printf(level, format, args...)` for formatted logging with an explicit log level.
+- Added `Logger.SetThresholdMode(bool)` to switch filtering from legacy severity-index ordering to threshold-based ordering.
+- Added `LogLevel.SameLevel`, `LogLevel.SameThreshold`, and `LogLevel.Equal` for severity-only, threshold-only, and full level comparisons.
+
+### Changed
+
+- Refactored log level definitions into a dedicated `levels.go` file.
+- Unified `Logger.Print` and `Logger.Println` through a shared internal implementation without changing their behavior.
+- Common helper constructors such as `NewInfoLogLevel` now also assign threshold values while preserving legacy severity indexes.
+- `LogLevel.Equal` now includes threshold configuration in full equality checks.
+- Expanded test coverage for `Logger.Printf`, HTTP level mapping, constructor behavior, threshold filtering, and backward compatibility.
+
+### Documentation
+
+- Improved GoDoc coverage for exported types, constructors, formatters, colors, HTTP helpers, and time layouts.
+- Documented threshold mode, threshold-aware constructors, level comparison helpers, and explicit-level formatted logging.
+- Expanded inline documentation for formatter tokens and default formatter behavior.
+- Updated English and Russian README files with threshold-mode examples and comparison guidance.
+
+### Compatibility
+
+- No breaking API changes.
+- Existing `Print`, `Println`, predefined levels, `Level/SetLevel`, and color APIs remain compatible.
+- Legacy severity ordering remains the default; threshold filtering is enabled only when `SetThresholdMode(true)` is called.
+- `SameLevel` remains severity-only for backward compatibility, even when levels carry threshold metadata.
+
 # v2.1.0
 
 This release expands sneklog color customization while preserving compatibility with the v2.0.1 API.

colors.go

@@ -5,12 +5,25 @@ import (
 	"strings"
 )
 
+// FgColor is a basic ANSI foreground color code.
 type FgColor uint8
+
+// BgColor is a basic ANSI background color code.
 type BgColor uint8
+
+// FgColor256 is an ANSI 256-color foreground value.
 type FgColor256 uint8
+
+// BgColor256 is an ANSI 256-color background value.
 type BgColor256 uint8
+
+// BgColorRGB is an ANSI truecolor background value encoded as RGB bytes.
 type BgColorRGB []uint8
+
+// FgColorRGB is an ANSI truecolor foreground value encoded as RGB bytes.
 type FgColorRGB []uint8
+
+// Attribute is an ANSI text attribute code.
 type Attribute uint8
 
 // NewBgColorRGB builds an RGB background color value.
@@ -23,6 +36,7 @@ func NewFgColorRGB(r, g, b uint8) FgColorRGB {
 	return FgColorRGB{r, g, b}
 }
 
+// Text attribute codes.
 const (
 	Reset Attribute = iota
 	Bold
@@ -35,6 +49,8 @@ const (
 	Conceal
 	CrossedOut
 )
+
+// Additional text attribute codes.
 const (
 	DoubleUnderline Attribute = iota + 21 // Can be disable bold on some terminals
 	DisableBold
@@ -45,6 +61,8 @@ const (
 	DisableConceal
 	DisableCrossedOut
 )
+
+// Basic foreground color codes.
 const (
 	FgNone          = 0
 	FgBlack FgColor = iota + 30
@@ -57,6 +75,8 @@ const (
 	FgWhite
 	FgDefault FgColor = 39
 )
+
+// Basic background color codes.
 const (
 	BgNone          = 0
 	BgBlack BgColor = iota + 40
@@ -69,6 +89,8 @@ const (
 	BgWhite
 	BgDefault BgColor = 49
 )
+
+// High-intensity foreground color codes.
 const (
 	FgHiBlack FgColor = iota + 90
 	FgHiRed
@@ -79,6 +101,8 @@ const (
 	FgHiCyan
 	FgHiWhite
 )
+
+// High-intensity background color codes.
 const (
 	BgHiBlack BgColor = iota + 100
 	BgHiRed
@@ -90,7 +114,7 @@ const (
 	BgHiWhite
 )
 
-// This attributes rarely used and not supported by all terminals.
+// Rarely used text attribute codes that are not supported by all terminals.
 const (
 	Border Attribute = iota + 51
 	Outline
@@ -99,6 +123,7 @@ const (
 	DisableUpperline
 )
 
+// ColorStringBuilder incrementally builds ANSI-colored strings.
 type ColorStringBuilder struct {
 	str string
 }

doc.go

@@ -17,6 +17,11 @@
 // passed to writers. Call SetFormatter on a writer to customize timestamps,
 // traceback fields, colors, and message layout.
 //
+// The package also provides helper constructors for common severities such as
+// NewInfoLogLevel and NewErrorLogLevel, plus predefined HTTP method-specific
+// levels such as HTTPGetLevel and HTTPPostLevel. Use LogLevelForMethod to map
+// an HTTP method to one of those predefined levels.
+//
 // Basic usage:
 //
 //	logger := sneklog.CreateLogger().
@@ -41,4 +46,8 @@
 // the logger and are closed by Logger.Close. Writers created from existing
 // io.Writer values through CreateTextWriter or CreateJsonWriter remain owned by
 // the caller and are not closed by the logger.
+//
+// LogLevel values can be compared with SameLevel when only the legacy severity
+// index matters, with SameThreshold when only threshold filtering matters, or
+// with Equal when the full level configuration must match.
 package sneklog

examples/main.go

@@ -32,6 +32,7 @@ func main() {
 	jsonFormatter := sneklog.NewFormatter().
 		SetFormat("[%L] [%N] %m").
 		SetColorOutput(false).
+		SetJSONEscapeHTML(false).
 		SetTimeStampFormat(sneklog.Kitchen)
 
 	textStdout.SetFormatter(formatter)
@@ -62,6 +63,7 @@ func main() {
 		externalJSON,
 	)
 
+	logger.Infoln("Тест <>&")
 	logger.Infoln("service started")
 	logger.Warnln("cache miss")
 	logger.Errorln("request failed")

formatter.go

@@ -6,23 +6,36 @@ import (
 	"time"
 )
 
-// Formatter
+// Formatter configures how log records are rendered.
-// Format: %t - time, %N - name, %l - level, %L - level uppercase, %b - traceback, %B - full traceback, %m - message,
-// %M - method, %f - filename, %n - line number, %s - method signature, %p - full path
-// Example: "%t [%l] %N: %m (%f:%n %s)"
 //
-// TimeStampFormat: %Y - year, %m - month, %d - day, %H - hour, %M - minute, %S - second,
+// Format tokens:
-// %z - timezone(i.e. 0300), %Z - timezone(i.e. 03:00)
+//   - %t: time
-// Example: "%d.%m.%Y %H:%M:%S"
+//   - %N: name
+//   - %l: level
+//   - %L: uppercase level
+//   - %b: first traceback frame
+//   - %B: full traceback
+//   - %m: message
+//   - %M: method
+//   - %f: filename
+//   - %n: line number
+//   - %s: method signature
+//   - %p: full path
 //
-// TraceBackFormat: %M - method, %f - filename, %n - line number, %s - method signature, %p - full path
+// Example format: "%t [%l] %N: %m (%f:%n %s)"
+//
+// TimeStampFormat uses strftime-like directives such as %Y, %m, %d, %H, %M,
+// %S, %z, and %Z.
+//
+// TraceBackFormat supports the traceback-related tokens %M, %f, %n, %s, and %p.
 type Formatter struct {
 	Format           string
 	MessageSeparator string
 
-	// JSONTraceBackPath
+	// JSONTraceBackPath enables full file paths in formatted traceback fields.
-	// If true, in traceback will be path to file, otherwise only filename.
 	JSONTraceBackPath bool
+	// JSONEscapeHTML controls whether JSON output escapes HTML-sensitive characters.
+	JSONEscapeHTML     bool
 	TimeStampFormat    string
 	TraceBackFormat    string
 	TraceBackSeparator string
@@ -31,6 +44,7 @@ type Formatter struct {
 	ColorOnlyStdout bool
 }
 
+// DefaultTextFormatter is the default formatter used by text writers.
 var DefaultTextFormatter = &Formatter{
 	Format:             "%t %l %N: %m",
 	MessageSeparator:   " ",
@@ -40,8 +54,11 @@ var DefaultTextFormatter = &Formatter{
 	ColorOutput:        true,
 	ColorOnlyStdout:    true,
 }
+
+// DefaultJsonFormatter is the default formatter used by JSON writers.
 var DefaultJsonFormatter = &Formatter{
 	Format:           "%m",
+	JSONEscapeHTML:   true,
 	MessageSeparator: " ",
 	TimeStampFormat:  RFC3339,
 	ColorOutput:      false,
@@ -52,6 +69,7 @@ func NewFormatter() *Formatter {
 	return &Formatter{
 		Format:             DefaultTextFormatter.Format,
 		MessageSeparator:   DefaultTextFormatter.MessageSeparator,
+		JSONEscapeHTML:     true,
 		TimeStampFormat:    DefaultTextFormatter.TimeStampFormat,
 		TraceBackFormat:    DefaultTextFormatter.TraceBackFormat,
 		TraceBackSeparator: DefaultTextFormatter.TraceBackSeparator,
@@ -72,6 +90,18 @@ func (f *Formatter) SetMessageSeparator(separator string) *Formatter {
 	return f
 }
 
+// SetJSONTraceBackPath enables or disables full file paths in formatted traceback fields.
+func (f *Formatter) SetJSONTraceBackPath(set bool) *Formatter {
+	f.JSONTraceBackPath = set
+	return f
+}
+
+// SetJSONEscapeHTML enables or disables HTML escaping in JSON output.
+func (f *Formatter) SetJSONEscapeHTML(escape bool) *Formatter {
+	f.JSONEscapeHTML = escape
+	return f
+}
+
 // SetTimeStampFormat sets the strftime-like format used for timestamps.
 func (f *Formatter) SetTimeStampFormat(format string) *Formatter {
 	f.TimeStampFormat = format

http.go

@@ -0,0 +1,47 @@
+package sneklog
+
+import "net/http"
+
+// HTTP method-specific log levels.
+var (
+	HTTPGetLevel    = NewInfoLogLevelWithColors("get", FgGreen, BgNone)
+	HTTPHeadLevel   = NewInfoLogLevelWithColors("head", FgCyan, BgNone)
+	HTTPPostLevel   = NewInfoLogLevelWithColors("post", FgBlue, BgNone)
+	HTTPPutLevel    = NewInfoLogLevelWithColors("put", FgYellow, BgNone)
+	HTTPPatchLevel  = NewInfoLogLevelWithColors("patch", FgMagenta, BgNone)
+	HTTPDeleteLevel = NewInfoLogLevelWithColors("delete", FgRed, BgNone)
+)
+
+// Additional HTTP method-specific log levels.
+var (
+	HTTPOptionsLevel = NewDebugLogLevelWithColors("options", FgWhite, BgNone)
+	HTTPConnectLevel = NewDebugLogLevelWithColors("connect", FgCyan, BgNone)
+	HTTPTraceLevel   = NewDebugLogLevelWithColors("trace", FgWhite, BgNone)
+	HTTPUnknownLevel = NewDebugLogLevelWithColors("http", FgWhite, BgNone)
+)
+
+// LogLevelForMethod returns the predefined log level associated with an HTTP method.
+func LogLevelForMethod(method string) LogLevel {
+	switch method {
+	case http.MethodGet:
+		return HTTPGetLevel
+	case http.MethodHead:
+		return HTTPHeadLevel
+	case http.MethodPost:
+		return HTTPPostLevel
+	case http.MethodPut:
+		return HTTPPutLevel
+	case http.MethodPatch:
+		return HTTPPatchLevel
+	case http.MethodDelete:
+		return HTTPDeleteLevel
+	case http.MethodOptions:
+		return HTTPOptionsLevel
+	case http.MethodConnect:
+		return HTTPConnectLevel
+	case http.MethodTrace:
+		return HTTPTraceLevel
+	default:
+		return HTTPUnknownLevel
+	}
+}

io.go

@@ -83,10 +83,10 @@ func (l *Logger) Debugln(m ...any) {
 	l.Println(DEBUG, m...)
 }
 
-// Print write message without trailing "\n"
+func (l *Logger) print(level LogLevel, newline bool, m ...any) {
-// Good for database
+	if l.threshold && l.level.th < level.th {
-func (l *Logger) Print(level LogLevel, m ...any) {
+		return
-	if l.level.n < level.n {
+	} else if l.level.n < level.n {
 		return
 	}
 	if len(l.writers) == 0 {
@@ -94,30 +94,10 @@ func (l *Logger) Print(level LogLevel, m ...any) {
 	}
 
 	tb := getFullTraceback(1)
-	for _, writer := range l.writers {
+	messages := l.replaceAll(m...)
-		if writer == nil {
+	if newline {
-			continue
+		messages = append(messages, any("\n"))
 	}
-		err := writer.Print(level, l.prefix, tb, l.replaceAll(m...)...)
-		if err != nil {
-			l.reportWriterError(err)
-		}
-	}
-}
-
-// Println
-// Docker requires "\n" at end to write to log.
-// print not work for docker, otherwise it will work and write into stdout
-func (l *Logger) Println(level LogLevel, m ...any) {
-	if l.level.n < level.n {
-		return
-	}
-	if len(l.writers) == 0 {
-		return
-	}
-
-	tb := getFullTraceback(1)
-	messages := append(append(make([]any, 0, len(m)+1), l.replaceAll(m...)...), "\n")
 	for _, writer := range l.writers {
 		if writer == nil {
 			continue
@@ -129,6 +109,17 @@ func (l *Logger) Println(level LogLevel, m ...any) {
 	}
 }
 
+// Print logs a message without appending a trailing newline semantic.
+func (l *Logger) Print(level LogLevel, m ...any) { l.print(level, false, m...) }
+
+// Println logs a message and appends a trailing newline semantic for writers that need it.
+func (l *Logger) Println(level LogLevel, m ...any) { l.print(level, true, m...) }
+
+// Printf formats according to a format specifier and logs the resulting message.
+func (l *Logger) Printf(level LogLevel, format string, args ...any) {
+	l.print(level, false, fmt.Sprintf(format, args...))
+}
+
 // reportWriterError writes internal writer failures directly to stderr to avoid
 // re-entering the same logger path that just failed.
 func (l *Logger) reportWriterError(err error) {

levels.go

@@ -0,0 +1,269 @@
+package sneklog
+
+// Predefined log levels.
+var (
+	INFO  = NewInfoLogLevelWithColors("info", FgWhite, BgNone)
+	WARN  = NewWarnLogLevelWithColors("warn", FgHiYellow, BgNone)
+	ERROR = NewErrorLogLevelWithColors("error", FgHiRed, BgNone)
+	FATAL = NewFatalLogLevelWithColors("fatal", FgRed, BgNone)
+	DEBUG = NewDebugLogLevelWithColors("debug", FgGreen, BgNone)
+)
+
+// LogLevel describes a logging severity.
+type LogLevel struct {
+	n  uint8
+	th uint8
+	t  string
+
+	fg    FgColor
+	fg256 FgColor256
+	fgRgb FgColorRGB
+
+	bg    BgColor
+	bg256 BgColor256
+	bgRgb BgColorRGB
+
+	attrs []Attribute
+}
+
+// NewLogLevel creates a log level without predefined colors.
+// Deprecated: use NewThresholdLogLevel. This function will be removed in v3.
+func NewLogLevel(index uint8, name string) LogLevel {
+	return NewLogLevelWithColors(index, name, 0, 0)
+}
+
+// NewLogLevelWithColors creates a log level with ANSI foreground and background colors.
+// Deprecated: use NewThresholdLogLevelWithColors. This function will be removed in v3.
+func NewLogLevelWithColors(index uint8, name string, fg FgColor, bg BgColor) LogLevel {
+	return LogLevel{n: index, t: name, fg: fg, bg: bg, attrs: []Attribute{}}
+}
+
+// NewThresholdLogLevel creates a log level with both a legacy severity index and
+// a threshold value used when Logger.SetThresholdMode(true) is enabled.
+func NewThresholdLogLevel(index, th uint8, name string) LogLevel {
+	return NewThresholdLogLevelWithColors(index, th, name, FgNone, BgNone)
+}
+
+// NewThresholdLogLevelWithColors creates a log level with both a legacy
+// severity index and a threshold value, plus ANSI foreground and background
+// colors.
+func NewThresholdLogLevelWithColors(index, th uint8, name string, fg FgColor, bg BgColor) LogLevel {
+	return LogLevel{n: index, th: th, t: name, fg: fg, bg: bg, attrs: []Attribute{}}
+}
+
+// NewInfoLogLevel creates an info-level log level without predefined colors.
+func NewInfoLogLevel(name string) LogLevel { return NewThresholdLogLevel(0, 10, name) }
+
+// NewInfoLogLevelWithColors creates an info-level log level with ANSI colors.
+func NewInfoLogLevelWithColors(name string, fg FgColor, bg BgColor) LogLevel {
+	return NewThresholdLogLevelWithColors(0, 10, name, fg, bg)
+}
+
+// NewWarnLogLevel creates a warn-level log level without predefined colors.
+func NewWarnLogLevel(name string) LogLevel { return NewThresholdLogLevel(1, 20, name) }
+
+// NewWarnLogLevelWithColors creates a warn-level log level with ANSI colors.
+func NewWarnLogLevelWithColors(name string, fg FgColor, bg BgColor) LogLevel {
+	return NewThresholdLogLevelWithColors(1, 20, name, fg, bg)
+}
+
+// NewErrorLogLevel creates an error-level log level without predefined colors.
+func NewErrorLogLevel(name string) LogLevel { return NewThresholdLogLevel(2, 30, name) }
+
+// NewErrorLogLevelWithColors creates an error-level log level with ANSI colors.
+func NewErrorLogLevelWithColors(name string, fg FgColor, bg BgColor) LogLevel {
+	return NewThresholdLogLevelWithColors(2, 30, name, fg, bg)
+}
+
+// NewFatalLogLevel creates a fatal-level log level without predefined colors.
+func NewFatalLogLevel(name string) LogLevel { return NewThresholdLogLevel(3, 40, name) }
+
+// NewFatalLogLevelWithColors creates a fatal-level log level with ANSI colors.
+func NewFatalLogLevelWithColors(name string, fg FgColor, bg BgColor) LogLevel {
+	return NewThresholdLogLevelWithColors(3, 40, name, fg, bg)
+}
+
+// NewDebugLogLevel creates a debug-level log level without predefined colors.
+func NewDebugLogLevel(name string) LogLevel { return NewThresholdLogLevel(4, 0, name) }
+
+// NewDebugLogLevelWithColors creates a debug-level log level with ANSI colors.
+func NewDebugLogLevelWithColors(name string, fg FgColor, bg BgColor) LogLevel {
+	return NewThresholdLogLevelWithColors(4, 0, name, fg, bg)
+}
+
+// GetName returns the lowercase textual representation of the level.
+func (l *LogLevel) GetName() string { return l.t }
+
+// SetFgColor sets the ANSI foreground color and clears other foreground color modes.
+// Deprecated: use SetForegroundColor. This method will be removed in v3.
+func (l *LogLevel) SetFgColor(color FgColor) *LogLevel {
+	return l.SetForegroundColor(color)
+}
+
+// GetFgColor returns the ANSI foreground color for the level.
+// Deprecated: use GetForegroundColor. This method will be removed in v3.
+func (l *LogLevel) GetFgColor() FgColor { return l.GetForegroundColor() }
+
+// SetForegroundColor sets the ANSI foreground color and clears other foreground color modes.
+func (l *LogLevel) SetForegroundColor(color FgColor) *LogLevel {
+	l.fg = color
+	l.fg256 = 0
+	l.fgRgb = nil
+	return l
+}
+
+// GetForegroundColor returns the ANSI foreground color for the level.
+func (l *LogLevel) GetForegroundColor() FgColor { return l.fg }
+
+// SetForeground256Color sets the 256-color foreground and clears other foreground color modes.
+func (l *LogLevel) SetForeground256Color(color FgColor256) *LogLevel {
+	l.fg = 0
+	l.fg256 = color
+	l.fgRgb = nil
+	return l
+}
+
+// GetForeground256Color returns the configured 256-color foreground value.
+func (l *LogLevel) GetForeground256Color() FgColor256 { return l.fg256 }
+
+// SetForegroundRGB sets the RGB foreground color and clears other foreground color modes.
+func (l *LogLevel) SetForegroundRGB(r, g, b uint8) *LogLevel {
+	l.fg = 0
+	l.fg256 = 0
+	l.fgRgb = FgColorRGB{r, g, b}
+	return l
+}
+
+// GetForegroundRGB returns the configured RGB foreground value.
+func (l *LogLevel) GetForegroundRGB() FgColorRGB { return l.fgRgb }
+
+// SetBgColor sets the ANSI background color and clears other background color modes.
+// Deprecated: use SetBackgroundColor. This method will be removed in v3.
+func (l *LogLevel) SetBgColor(color BgColor) *LogLevel {
+	return l.SetBackgroundColor(color)
+}
+
+// GetBgColor returns the ANSI background color for the level.
+// Deprecated: use GetBackgroundColor. This method will be removed in v3.
+func (l *LogLevel) GetBgColor() BgColor { return l.GetBackgroundColor() }
+
+// SetBackgroundColor sets the ANSI background color and clears other background color modes.
+func (l *LogLevel) SetBackgroundColor(color BgColor) *LogLevel {
+	l.bg = color
+	l.bg256 = 0
+	l.bgRgb = nil
+	return l
+}
+
+// GetBackgroundColor returns the ANSI background color for the level.
+func (l *LogLevel) GetBackgroundColor() BgColor { return l.bg }
+
+// SetBackground256Color sets the 256-color background and clears other background color modes.
+func (l *LogLevel) SetBackground256Color(color BgColor256) *LogLevel {
+	l.bg = 0
+	l.bg256 = color
+	l.bgRgb = nil
+	return l
+}
+
+// GetBackground256Color returns the configured 256-color background value.
+func (l *LogLevel) GetBackground256Color() BgColor256 { return l.bg256 }
+
+// SetBackgroundRGB sets the RGB background color and clears other background color modes.
+func (l *LogLevel) SetBackgroundRGB(r, g, b uint8) *LogLevel {
+	l.bg = 0
+	l.bg256 = 0
+	l.bgRgb = BgColorRGB{r, g, b}
+	return l
+}
+
+// GetBackgroundRGB returns the configured RGB background value.
+func (l *LogLevel) GetBackgroundRGB() BgColorRGB { return l.bgRgb }
+
+// AddAttribute appends an ANSI text attribute to the level.
+func (l *LogLevel) AddAttribute(a Attribute) *LogLevel {
+	l.attrs = append(l.attrs, a)
+	return l
+}
+
+// RemoveAttribute removes all matching ANSI text attributes from the level.
+func (l *LogLevel) RemoveAttribute(a Attribute) *LogLevel {
+	attrs := make([]Attribute, 0)
+	for _, attr := range l.attrs {
+		if attr != a {
+			attrs = append(attrs, attr)
+		}
+	}
+	l.attrs = attrs
+	return l
+}
+
+// SetAttributes replaces the level attributes with a copy of the provided slice.
+func (l *LogLevel) SetAttributes(a []Attribute) *LogLevel {
+	attrs := make([]Attribute, len(a))
+	copy(attrs, a)
+	l.attrs = attrs
+	return l
+}
+
+// GetAttributes returns a copy of the configured ANSI text attributes.
+func (l *LogLevel) GetAttributes() []Attribute {
+	attrs := make([]Attribute, len(l.attrs))
+	copy(attrs, l.attrs)
+	return attrs
+}
+
+// SameLevel reports whether two log levels have the same severity index.
+// Deprecated: use SameThreshold for threshold-only comparisons or Equal for the
+// full level configuration. SameLevel remains severity-only for backward
+// compatibility and ignores threshold values.
+func (l *LogLevel) SameLevel(other LogLevel) bool {
+	return l.n == other.n
+}
+
+// SameThreshold reports whether two log levels have the same threshold value.
+func (l *LogLevel) SameThreshold(other LogLevel) bool {
+	return l.th == other.th
+}
+
+// Equal reports whether two log levels have identical configuration.
+func (l *LogLevel) Equal(other LogLevel) bool {
+	if l.t != other.t || l.n != other.n || l.th != other.th {
+		return false
+	}
+	if l.fg != other.fg || l.bg != other.bg {
+		return false
+	}
+
+	if l.fg256 != other.fg256 || l.bg256 != other.bg256 {
+		return false
+	}
+
+	if len(l.attrs) != len(other.attrs) {
+		return false
+	}
+	for i := range l.attrs {
+		if l.attrs[i] != other.attrs[i] {
+			return false
+		}
+	}
+
+	if len(l.fgRgb) != len(other.fgRgb) {
+		return false
+	}
+	for i := range l.fgRgb {
+		if l.fgRgb[i] != other.fgRgb[i] {
+			return false
+		}
+	}
+
+	if len(l.bgRgb) != len(other.bgRgb) {
+		return false
+	}
+	for i := range l.bgRgb {
+		if l.bgRgb[i] != other.bgRgb[i] {
+			return false
+		}
+	}
+	return true
+}

logger.go

@@ -7,154 +7,6 @@ import (
 	"strings"
 )
 
-// LogLevel describes a logging severity.
-type LogLevel struct {
-	n uint8
-	t string
-
-	fg    FgColor
-	fg256 FgColor256
-	fgRgb FgColorRGB
-
-	bg    BgColor
-	bg256 BgColor256
-	bgRgb BgColorRGB
-
-	attrs []Attribute
-}
-
-// NewLogLevel creates a log level without predefined colors.
-func NewLogLevel(index uint8, name string) LogLevel {
-	return LogLevel{n: index, t: name, attrs: []Attribute{}}
-}
-
-// NewLogLevelWithColors creates a log level with ANSI foreground and background colors.
-func NewLogLevelWithColors(index uint8, name string, fg FgColor, bg BgColor) LogLevel {
-	return LogLevel{n: index, t: name, fg: fg, bg: bg, attrs: []Attribute{}}
-}
-
-// GetName returns the lowercase textual representation of the level.
-func (l *LogLevel) GetName() string { return l.t }
-
-// SetFgColor sets the ANSI foreground color and clears other foreground color modes.
-// Deprecated: use SetForegroundColor. This method will be removed in v3.
-func (l *LogLevel) SetFgColor(color FgColor) *LogLevel {
-	return l.SetForegroundColor(color)
-}
-
-// GetFgColor returns the ANSI foreground color for the level.
-// Deprecated: use GetForegroundColor. This method will be removed in v3.
-func (l *LogLevel) GetFgColor() FgColor { return l.GetForegroundColor() }
-
-// SetForegroundColor sets the ANSI foreground color and clears other foreground color modes.
-func (l *LogLevel) SetForegroundColor(color FgColor) *LogLevel {
-	l.fg = color
-	l.fg256 = 0
-	l.fgRgb = nil
-	return l
-}
-
-// GetForegroundColor returns the ANSI foreground color for the level.
-func (l *LogLevel) GetForegroundColor() FgColor { return l.fg }
-
-// SetForeground256Color sets the 256-color foreground and clears other foreground color modes.
-func (l *LogLevel) SetForeground256Color(color FgColor256) *LogLevel {
-	l.fg = 0
-	l.fg256 = color
-	l.fgRgb = nil
-	return l
-}
-
-// GetForeground256Color returns the configured 256-color foreground value.
-func (l *LogLevel) GetForeground256Color() FgColor256 { return l.fg256 }
-
-// SetForegroundRGB sets the RGB foreground color and clears other foreground color modes.
-func (l *LogLevel) SetForegroundRGB(r, g, b uint8) *LogLevel {
-	l.fg = 0
-	l.fg256 = 0
-	l.fgRgb = FgColorRGB{r, g, b}
-	return l
-}
-
-// GetForegroundRGB returns the configured RGB foreground value.
-func (l *LogLevel) GetForegroundRGB() FgColorRGB { return l.fgRgb }
-
-// SetBgColor sets the ANSI background color and clears other background color modes.
-// Deprecated: use SetBackgroundColor. This method will be removed in v3.
-func (l *LogLevel) SetBgColor(color BgColor) *LogLevel {
-	return l.SetBackgroundColor(color)
-}
-
-// GetBgColor returns the ANSI background color for the level.
-// Deprecated: use GetBackgroundColor. This method will be removed in v3.
-func (l *LogLevel) GetBgColor() BgColor { return l.GetBackgroundColor() }
-
-// SetBackgroundColor sets the ANSI background color and clears other background color modes.
-func (l *LogLevel) SetBackgroundColor(color BgColor) *LogLevel {
-	l.bg = color
-	l.bg256 = 0
-	l.bgRgb = nil
-	return l
-}
-
-// GetBackgroundColor returns the ANSI background color for the level.
-func (l *LogLevel) GetBackgroundColor() BgColor { return l.bg }
-
-// SetBackground256Color sets the 256-color background and clears other background color modes.
-func (l *LogLevel) SetBackground256Color(color BgColor256) *LogLevel {
-	l.bg = 0
-	l.bg256 = color
-	l.bgRgb = nil
-	return l
-}
-
-// GetBackground256Color returns the configured 256-color background value.
-func (l *LogLevel) GetBackground256Color() BgColor256 { return l.bg256 }
-
-// SetBackgroundRGB sets the RGB background color and clears other background color modes.
-func (l *LogLevel) SetBackgroundRGB(r, g, b uint8) *LogLevel {
-	l.bg = 0
-	l.bg256 = 0
-	l.bgRgb = BgColorRGB{r, g, b}
-	return l
-}
-
-// GetBackgroundRGB returns the configured RGB background value.
-func (l *LogLevel) GetBackgroundRGB() BgColorRGB { return l.bgRgb }
-
-// AddAttribute appends an ANSI text attribute to the level.
-func (l *LogLevel) AddAttribute(a Attribute) *LogLevel {
-	l.attrs = append(l.attrs, a)
-	return l
-}
-
-// RemoveAttribute removes all matching ANSI text attributes from the level.
-func (l *LogLevel) RemoveAttribute(a Attribute) *LogLevel {
-	attrs := make([]Attribute, 0)
-	for _, attr := range l.attrs {
-		if attr != a {
-			attrs = append(attrs, attr)
-		}
-	}
-	l.attrs = attrs
-	return l
-}
-
-// SetAttributes replaces the level attributes with a copy of the provided slice.
-func (l *LogLevel) SetAttributes(a []Attribute) *LogLevel {
-	attrs := make([]Attribute, len(a))
-	copy(attrs, a)
-	l.attrs = attrs
-	return l
-}
-
-// GetAttributes returns a copy of the configured ANSI text attributes.
-func (l *LogLevel) GetAttributes() []Attribute {
-	attrs := make([]Attribute, len(l.attrs))
-	copy(attrs, l.attrs)
-	return attrs
-}
-
 // MethodTraceback describes a single stack frame attached to a log entry.
 type MethodTraceback struct {
 	Method    string `json:"method"`
@@ -164,23 +16,16 @@ type MethodTraceback struct {
 	FullPath  string `json:"fullPath"`
 }
 
-// Predefined log levels.
-var (
-	INFO  = NewLogLevelWithColors(0, "info", FgWhite, BgNone)
-	WARN  = NewLogLevelWithColors(1, "warn", FgHiYellow, BgNone)
-	ERROR = NewLogLevelWithColors(2, "error", FgHiRed, BgNone)
-	FATAL = NewLogLevelWithColors(3, "fatal", FgRed, BgNone)
-	DEBUG = NewLogLevelWithColors(4, "debug", FgGreen, BgNone)
-)
-
 // Logger routes log records to one or more configured writers.
 type Logger struct {
 	prefix string
 	level  LogLevel
+
 	writers   []LoggerWriter
 	replacers []replacer
 
 	jsonPretty bool
+	threshold  bool
 }
 
 // CreateLogger creates a logger with default settings.
@@ -239,6 +84,13 @@ func (l *Logger) SetJSONPretty(b bool) *Logger {
 	return l
 }
 
+// SetThresholdMode switches Logger.Print filtering from legacy severity-index
+// ordering to LogLevel threshold ordering.
+func (l *Logger) SetThresholdMode(b bool) *Logger {
+	l.threshold = b
+	return l
+}
+
 // AddWriters appends multiple writers to the logger.
 func (l *Logger) AddWriters(writers ...LoggerWriter) *Logger {
 	l.writers = append(l.writers, writers...)

logger_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
+	"net/http"
 	"os"
 	"strings"
 	"testing"
@@ -100,6 +101,180 @@ func TestLoggerPreservesMessageTypesWithoutReplacers(t *testing.T) {
 	}
 }
 
+func TestLoggerPrintfFormatsMessage(t *testing.T) {
+	writer := &stubLoggerWriter{}
+	logger := CreateLogger().
+		SetLevel(DEBUG).
+		AddWriter(writer)
+
+	logger.Printf(INFO, "status=%d %s", 200, "ok")
+
+	if writer.printCalls != 1 {
+		t.Fatalf("Printf() should write once, got %d calls", writer.printCalls)
+	}
+	if len(writer.messages) != 1 {
+		t.Fatalf("Printf() should produce one formatted message, got %d parts", len(writer.messages))
+	}
+	if got, ok := writer.messages[0].(string); !ok || got != "status=200 ok" {
+		t.Fatalf("Printf() should format message, got %#v", writer.messages)
+	}
+}
+
+func TestLoggerUsesSeverityOrderingWhenThresholdModeIsDisabled(t *testing.T) {
+	writer := &stubLoggerWriter{}
+	logger := CreateLogger().
+		SetLevel(NewThresholdLogLevel(1, 0, "warn")).
+		AddWriter(writer)
+
+	logger.Print(NewThresholdLogLevel(0, 100, "info"))
+	logger.Print(NewThresholdLogLevel(2, 0, "error"))
+
+	if writer.printCalls != 1 {
+		t.Fatalf("severity mode should allow only lower-or-equal severity levels, got %d writes", writer.printCalls)
+	}
+}
+
+func TestLoggerUsesThresholdOrderingWhenThresholdModeIsEnabled(t *testing.T) {
+	writer := &stubLoggerWriter{}
+	logger := CreateLogger().
+		SetLevel(NewThresholdLogLevel(4, 20, "custom")).
+		SetThresholdMode(true).
+		AddWriter(writer)
+
+	logger.Print(NewThresholdLogLevel(4, 10, "debug"))
+	logger.Print(NewThresholdLogLevel(0, 30, "info"))
+
+	if writer.printCalls != 1 {
+		t.Fatalf("threshold mode should allow only entries at or below the configured threshold, got %d writes", writer.printCalls)
+	}
+}
+
+func TestDeprecatedLevelMethodKeepsLegacySeverityBehavior(t *testing.T) {
+	writer := &stubLoggerWriter{}
+	logger := CreateLogger().
+		Level(FATAL).
+		AddWriter(writer)
+
+	logger.Print(INFO, "info")
+	logger.Print(WARN, "warn")
+	logger.Print(ERROR, "error")
+	logger.Print(FATAL, "fatal")
+	logger.Print(DEBUG, "debug")
+
+	if writer.printCalls != 4 {
+		t.Fatalf("Level(FATAL) should keep legacy behavior and allow INFO/WARN/ERROR/FATAL only, got %d writes", writer.printCalls)
+	}
+}
+
+func TestSameLevelIgnoresThresholdDifferencesForCompatibility(t *testing.T) {
+	legacy := NewLogLevel(1, "warn")
+	threshold := NewThresholdLogLevel(1, 20, "warn")
+
+	if !legacy.SameLevel(threshold) {
+		t.Fatalf("SameLevel() should continue comparing only severity index")
+	}
+	if legacy.Equal(threshold) {
+		t.Fatalf("Equal() should distinguish levels with different threshold configuration")
+	}
+}
+
+func TestSameThresholdComparesOnlyThresholdValue(t *testing.T) {
+	first := NewThresholdLogLevel(1, 20, "warn")
+	second := NewThresholdLogLevel(9, 20, "custom")
+	third := NewThresholdLogLevel(1, 30, "warn")
+
+	if !first.SameThreshold(second) {
+		t.Fatalf("SameThreshold() should ignore severity and compare threshold only")
+	}
+	if first.SameThreshold(third) {
+		t.Fatalf("SameThreshold() should detect different threshold values")
+	}
+}
+
+func TestLogLevelForMethodReturnsExpectedLevels(t *testing.T) {
+	tests := []struct {
+		name   string
+		method string
+		want   LogLevel
+	}{
+		{name: "get", method: http.MethodGet, want: HTTPGetLevel},
+		{name: "head", method: http.MethodHead, want: HTTPHeadLevel},
+		{name: "post", method: http.MethodPost, want: HTTPPostLevel},
+		{name: "put", method: http.MethodPut, want: HTTPPutLevel},
+		{name: "patch", method: http.MethodPatch, want: HTTPPatchLevel},
+		{name: "delete", method: http.MethodDelete, want: HTTPDeleteLevel},
+		{name: "options", method: http.MethodOptions, want: HTTPOptionsLevel},
+		{name: "connect", method: http.MethodConnect, want: HTTPConnectLevel},
+		{name: "trace", method: http.MethodTrace, want: HTTPTraceLevel},
+		{name: "unknown", method: "PROPFIND", want: HTTPUnknownLevel},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := LogLevelForMethod(tt.method)
+			if got.n != tt.want.n || got.t != tt.want.t || got.fg != tt.want.fg || got.bg != tt.want.bg {
+				t.Fatalf("LogLevelForMethod(%q) = %#v, want %#v", tt.method, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNewLevelConstructorsSetExpectedSeverity(t *testing.T) {
+	tests := []struct {
+		name   string
+		got    LogLevel
+		want   LogLevel
+		wantTh uint8
+	}{
+		{name: "info", got: NewInfoLogLevel("custom"), want: INFO, wantTh: 10},
+		{name: "warn", got: NewWarnLogLevel("custom"), want: WARN, wantTh: 20},
+		{name: "error", got: NewErrorLogLevel("custom"), want: ERROR, wantTh: 30},
+		{name: "fatal", got: NewFatalLogLevel("custom"), want: FATAL, wantTh: 40},
+		{name: "debug", got: NewDebugLogLevel("custom"), want: DEBUG, wantTh: 0},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.got.n != tt.want.n {
+				t.Fatalf("%s severity = %d, want %d", tt.name, tt.got.n, tt.want.n)
+			}
+			if tt.got.th != tt.wantTh {
+				t.Fatalf("%s threshold = %d, want %d", tt.name, tt.got.th, tt.wantTh)
+			}
+			if tt.got.GetName() != "custom" {
+				t.Fatalf("%s constructor should preserve name, got %q", tt.name, tt.got.GetName())
+			}
+		})
+	}
+}
+
+func TestNewLevelConstructorsWithColorsSetExpectedFields(t *testing.T) {
+	info := NewInfoLogLevelWithColors("info-custom", FgBlue, BgYellow)
+	if info.n != INFO.n || info.GetName() != "info-custom" || info.fg != FgBlue || info.bg != BgYellow {
+		t.Fatalf("NewInfoLogLevelWithColors() = %#v", info)
+	}
+
+	warn := NewWarnLogLevelWithColors("warn-custom", FgMagenta, BgCyan)
+	if warn.n != WARN.n || warn.GetName() != "warn-custom" || warn.fg != FgMagenta || warn.bg != BgCyan {
+		t.Fatalf("NewWarnLogLevelWithColors() = %#v", warn)
+	}
+
+	errLevel := NewErrorLogLevelWithColors("error-custom", FgRed, BgWhite)
+	if errLevel.n != ERROR.n || errLevel.GetName() != "error-custom" || errLevel.fg != FgRed || errLevel.bg != BgWhite {
+		t.Fatalf("NewErrorLogLevelWithColors() = %#v", errLevel)
+	}
+
+	fatal := NewFatalLogLevelWithColors("fatal-custom", FgHiRed, BgBlack)
+	if fatal.n != FATAL.n || fatal.GetName() != "fatal-custom" || fatal.fg != FgHiRed || fatal.bg != BgBlack {
+		t.Fatalf("NewFatalLogLevelWithColors() = %#v", fatal)
+	}
+
+	debug := NewDebugLogLevelWithColors("debug-custom", FgGreen, BgDefault)
+	if debug.n != DEBUG.n || debug.GetName() != "debug-custom" || debug.fg != FgGreen || debug.bg != BgDefault {
+		t.Fatalf("NewDebugLogLevelWithColors() = %#v", debug)
+	}
+}
+
 func TestCreateTextWriterCloseOnNonCloserIsNoOp(t *testing.T) {
 	writer := CreateTextWriter(&bytes.Buffer{})
 	if err := writer.Close(); err != nil {
@@ -167,6 +342,42 @@ func TestJsonWriterPrintAllowsEmptyMessages(t *testing.T) {
 	}
 }
 
+func TestJsonWriterPrintDoesNotAppendNewline(t *testing.T) {
+	var buf bytes.Buffer
+	writer := CreateJsonWriter(&buf, false)
+
+	if err := writer.Print(INFO, "TEST", nil, "hello"); err != nil {
+		t.Fatalf("Print() error = %v", err)
+	}
+
+	if bytes.HasSuffix(buf.Bytes(), []byte("\n")) {
+		t.Fatalf("Print() should not append newline, got %q", buf.String())
+	}
+}
+
+func TestJsonWriterSetJSONEscapeHTML(t *testing.T) {
+	var escaped bytes.Buffer
+	escapedWriter := CreateJsonWriter(&escaped, false)
+
+	if err := escapedWriter.Print(INFO, "TEST", nil, "<>&"); err != nil {
+		t.Fatalf("Print() with default formatter error = %v", err)
+	}
+	if strings.Contains(escaped.String(), "<>&") {
+		t.Fatalf("default JSON output should escape HTML-sensitive characters, got %q", escaped.String())
+	}
+
+	var raw bytes.Buffer
+	rawWriter := CreateJsonWriter(&raw, false).
+		SetFormatter(NewFormatter().SetFormat("%m").SetJSONEscapeHTML(false))
+
+	if err := rawWriter.Print(INFO, "TEST", nil, "<>&"); err != nil {
+		t.Fatalf("Print() with SetJSONEscapeHTML(false) error = %v", err)
+	}
+	if !strings.Contains(raw.String(), "<>&") {
+		t.Fatalf("SetJSONEscapeHTML(false) should preserve HTML-sensitive characters, got %q", raw.String())
+	}
+}
+
 func TestJsonWriterPrintPreservesTrailingNewlineSemantic(t *testing.T) {
 	var buf bytes.Buffer
 	writer := CreateJsonWriter(&buf, false)
@@ -179,6 +390,9 @@ func TestJsonWriterPrintPreservesTrailingNewlineSemantic(t *testing.T) {
 	if !bytes.HasSuffix(data, []byte("\n")) {
 		t.Fatalf("JSON output should end with newline, got %q", data)
 	}
+	if bytes.HasSuffix(bytes.TrimSuffix(data, []byte("\n")), []byte("\n")) {
+		t.Fatalf("JSON output should end with exactly one newline, got %q", data)
+	}
 
 	var message LoggerJsonMessage
 	if err := json.Unmarshal(bytes.TrimSuffix(data, []byte("\n")), &message); err != nil {

time_format.go

@@ -2,6 +2,7 @@ package sneklog
 
 import "strings"
 
+// Predefined strftime-like time layouts.
 const (
 	Layout   = "%m/%d %I:%M:%S%p '%y %z"
 	ANSIC    = "%a %b %e %H:%M:%S %Y"

writers.go

@@ -1,6 +1,7 @@
 package sneklog
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -145,21 +146,27 @@ func (w *LoggerJsonWriter) Print(level LogLevel, prefix string, traceback []*Met
 		Message:   s,
 		Traceback: traceback,
 	}
-	var data []byte
+
-	var err error
+	buf := bytes.NewBuffer(nil)
+	enc := json.NewEncoder(buf)
+	enc.SetEscapeHTML(f.JSONEscapeHTML)
 	if w.pretty {
-		data, err = json.MarshalIndent(m, "", "  ")
+		enc.SetIndent("", "  ")
-	} else {
-		data, err = json.Marshal(m)
 	}
+
+	err := enc.Encode(m)
 	if err != nil {
 		return err
 	}
-	if newline {
+	data := buf.Bytes()
-		data = append(data, '\n')
+	if !newline {
+		data = bytes.TrimSuffix(data, []byte("\n"))
 	}
-	_, err = w.Write(data)
+	_, err = w.writer.Write(data)
+	if err != nil {
 		return err
+	}
+	return nil
 }
 
 // Close closes the owned writer, if any.