TableWriter for Go

tablewriter is a Go library for generating rich text-based tables with support for multiple output formats, including ASCII, Unicode, Markdown, HTML, and colorized terminals. Perfect for CLI tools, logs, and web applications.

Key Features

• Multi-format rendering: ASCII, Unicode, Markdown, HTML, ANSI-colored
• Advanced styling: Cell merging, alignment, padding, borders
• Flexible input: CSV, structs, slices, or streaming data
• High performance: Minimal allocations, buffer reuse
• Modern features: Generics support, hierarchical merging, real-time streaming

Installation

Legacy Version (v0.0.5)

For use with legacy applications:

go get github.com/olekukonko/tablewriter@v0.0.5

Latest Version

The latest stable version

go get github.com/olekukonko/tablewriter@v1.1.3

Warning: Version v1.0.0 contains missing functionality and should not be used.

Version Guidance - Legacy: Use v0.0.5 (stable) - New Features: Use @latest (includes generics, super fast streaming APIs) - Legacy Docs: See README_LEGACY.md

Why TableWriter?

• CLI Ready: Instant compatibility with terminal outputs
• Database Friendly: Native support for sql.Null* types
• Secure: Auto-escaping for HTML/Markdown
• Extensible: Custom renderers and formatters

Quick Example

package main

import (
    "github.com/olekukonko/tablewriter"
    "os"
)

func main() {
    data := [][]string{
        {"Package", "Version", "Status"},
        {"tablewriter", "v0.0.5", "legacy"},
        {"tablewriter", "v1.1.3", "latest"},
    }

    table := tablewriter.NewWriter(os.Stdout)
    table.Header(data[0])
    table.Bulk(data[1:])
    table.Render()
}

Output:

┌─────────────┬─────────┬────────┐
│   PACKAGE   │ VERSION │ STATUS │
├─────────────┼─────────┼────────┤
│ tablewriter │ v0.0.5  │ legacy │
│ tablewriter │ v1.1.3  │ latest │
└─────────────┴─────────┴────────┘

Detailed Usage

Create a table with NewTable or NewWriter, configure it using options or a Config struct, add data with Append or Bulk, and render to an io.Writer. Use renderers like Blueprint (ASCII), HTML, Markdown, Colorized, or Ocean (streaming).

Here's how the API primitives map to the generated ASCII table:

API Call                                  ASCII Table Component
--------                                  ---------------------

table.Header([]string{"NAME", "AGE"})     ┌──────┬─────┐  ← Borders.Top
                                          │ NAME │ AGE │  ← Header row
                                          ├──────┼─────┤  ← Lines.ShowTop (header separator)

table.Append([]string{"Alice", "25"})     │ Alice│ 25  │  ← Data row
                                          ├──────┼─────┤  ← Separators.BetweenRows

table.Append([]string{"Bob", "30"})       │ Bob  │ 30  │  ← Data row
                                          ├──────┼─────┤  ← Lines.ShowBottom (footer separator)

table.Footer([]string{"Total", "2"})      │ Total│ 2   │  ← Footer row
                                          └──────┴─────┘  ← Borders.Bottom

The core components include:

• Renderer - Implements the core interface for converting table data into output formats. Available renderers include Blueprint (ASCII), HTML, Markdown, Colorized (ASCII with color), Ocean (streaming ASCII), and SVG.

• Config - The root configuration struct that controls all table behavior and appearance

• Behavior - Controls high-level rendering behaviors including auto-hiding empty columns, trimming row whitespace, header/footer visibility, and compact mode for optimized merged cell calculations
• CellConfig - The comprehensive configuration template used for table sections (header, row, footer). Combines formatting, padding, alignment, filtering, callbacks, and width constraints with global and per-column control

• StreamConfig - Configuration for streaming mode including enable/disable state and strict column validation

• Rendition - Defines how a renderer formats tables and contains the complete visual styling configuration

• Borders - Control the outer frame visibility (top, bottom, left, right edges) of the table
• Lines - Control horizontal boundary lines (above/below headers, above footers) that separate different table sections
• Separators - Control the visibility of separators between rows and between columns within the table content
• Symbols - Define the characters used for drawing table borders, corners, and junctions

These components can be configured with various tablewriter.With*() functional options when creating a new table.

Examples

Basic Examples

1. Simple Tables

Create a basic table with headers and rows.

default

package main

import (
    "fmt"
    "github.com/olekukonko/tablewriter"
    "os"
)

type Age int

func (a Age) String() string {
    return fmt.Sprintf("%d yrs", a)
}

func main() {
    data := [][]any{
        {"Alice", Age(25), "New York"},
        {"Bob", Age(30), "Boston"},
    }

    table := tablewriter.NewTable(os.Stdout)
    table.Header("Name", "Age", "City")
    table.Bulk(data)
    table.Render()
}

Output:

┌───────┬────────┬──────────┐
│ NAME  │  AGE   │   CITY   │
├───────┼────────┼──────────┤
│ Alice │ 25 yrs │ New York │
│ Bob   │ 30 yrs │ Boston   │
└───────┴────────┴──────────┘

with customization

package main

import (
    "fmt"
    "github.com/olekukonko/tablewriter"
    "github.com/olekukonko/tablewriter/renderer"
    "github.com/olekukonko/tablewriter/tw"
    "os"
)

type Age int

func (a Age) String() string {
    return fmt.Sprintf("%d yrs", a)
}

func main() {
    data := [][]any{
        {"Alice", Age(25), "New York"},
        {"Bob", Age(30), "Boston"},
    }

    symbols := tw.NewSymbolCustom("Nature").
        WithRow("~").
        WithColumn("|").
        WithTopLeft("🌱").
        WithTopMid("🌿").
        WithTopRight("🌱").
        WithMidLeft("🍃").
        WithCenter("❀").
        WithMidRight("🍃").
        WithBottomLeft("🌻").
        WithBottomMid("🌾").
        WithBottomRight("🌻")

    table := tablewriter.NewTable(os.Stdout, tablewriter.WithRenderer(renderer.NewBlueprint(tw.Rendition{Symbols: symbols})))
    table.Header("Name", "Age", "City")
    table.Bulk(data)
    table.Render()
}

🌱~~~~~~❀~~~~~~~~❀~~~~~~~~~🌱
| NAME  |  AGE   |   CITY   |
🍃~~~~~~❀~~~~~~~~❀~~~~~~~~~🍃
| Alice | 25 yrs | New York |
| Bob   | 30 yrs | Boston   |
🌻~~~~~~❀~~~~~~~~❀~~~~~~~~~🌻

See symbols example for more

2. Markdown Table

Generate a Markdown table for documentation.

package main

import (
    "fmt"
    "github.com/olekukonko/tablewriter"
    "github.com/olekukonko/tablewriter/renderer"
    "os"
    "strings"
    "unicode"
)

type Name struct {
    First string
    Last  string
}

// this will be ignored since  Format() is present
func (n Name) String() string {
    return fmt.Sprintf("%s %s", n.First, n.Last)
}

// Note: Format() overrides String() if both exist.
func (n Name) Format() string {
    return fmt.Sprintf("%s %s", n.clean(n.First), n.clean(n.Last))
}

// clean ensures the first letter is capitalized and the rest are lowercase
func (n Name) clean(s string) string {
    s = strings.TrimSpace(strings.ToLower(s))
    words := strings.Fields(s)
    s = strings.Join(words, "")

    if s == "" {
        return s
    }
    // Capitalize the first letter
    runes := []rune(s)
    runes[0] = unicode.ToUpper(runes[0])
    return string(runes)
}

type Age int

// Age int will be ignore and string will be used
func (a Age) String() string {
    return fmt.Sprintf("%d yrs", a)
}

func main() {
    data := [][]any{
        {Name{"Al  i  CE", " Ma  SK"}, Age(25), "New York"},
        {Name{"bOb", "mar   le   y"}, Age(30), "Boston"},
    }

    table := tablewriter.NewTable(os.Stdout,
        tablewriter.WithRenderer(renderer.NewMarkdown()),
    )

    table.Header([]string{"Name", "Age", "City"})
    table.Bulk(data)
    table.Render()
}

Output:

|    NAME    |  AGE   |   CITY   |
|:----------:|:------:|:--------:|
| Alice Mask | 25 yrs | New York |
| Bob Marley | 30 yrs | Boston   |

3. CSV Input

Create a table from a CSV file with custom row alignment.

package main

import (
    "github.com/olekukonko/tablewriter"
    "github.com/olekukonko/tablewriter/tw"
    "log"
    "os"
)

func main() {
    // Assuming "test.csv" contains: "First Name,Last Name,SSN\nJohn,Barry,123456\nKathy,Smith,687987"
    table, err := tablewriter.NewCSV(os.Stdout, "test.csv", true)
    if err != nil {
        log.Fatalf("Error: %v", err)
    }

    table.Configure(func(config *tablewriter.Config) {
        config.Row.Alignment.Global = tw.AlignLeft
    })
    table.Render()
}

Output:

┌────────────┬───────────┬─────────┐
│ FIRST NAME │ LAST NAME │   SSN   │
├────────────┼───────────┼─────────┤
│ John       │ Barry     │ 123456  │
│ Kathy      │ Smith     │ 687987  │
└────────────┴───────────┴─────────┘

Advanced Examples

4. Colorized Table with Long Values

Create a colorized table with wrapped long values, per-column colors, and a styled footer (inspired by TestColorizedLongValues and TestColorizedCustomColors).

package main

import (
    "github.com/fatih/color"
    "github.com/olekukonko/tablewriter"
    "github.com/olekukonko/tablewriter/renderer"
    "github.com/olekukonko/tablewriter/tw"
    "os"
)

func main() {
    data := [][]string{
        {"1", "This is a very long description that needs wrapping for readability", "OK"},
        {"2", "Short description", "DONE"},
        {"3", "Another lengthy description requiring truncation or wrapping", "ERROR"},
    }

    // Configure colors: green headers, cyan/magenta rows, yellow footer
    colorCfg := renderer.ColorizedConfig{
        Header: renderer.Tint{
            FG: renderer.Colors{color.FgGreen, color.Bold}, // Green bold headers
            BG: renderer.Colors{color.BgHiWhite},
        },
        Column: renderer.Tint{
            FG: renderer.Colors{color.FgCyan}, // Default cyan for rows
            Columns: []renderer.Tint{
                {FG: renderer.Colors{color.FgMagenta}}, // Magenta for column 0
                {},                                     // Inherit default (cyan)
                {FG: renderer.Colors{color.FgHiRed}},   // High-intensity red for column 2
            },
        },
        Footer: renderer.Tint{
            FG: renderer.Colors{color.FgYellow, color.Bold}, // Yellow bold footer
            Columns: []renderer.Tint{
                {},                                      // Inherit default
                {FG: renderer.Colors{color.FgHiYellow}}, // High-intensity yellow for column 1
                {},                                      // Inherit default
            },
        },
        Border:    renderer.Tint{FG: renderer.Colors{color.FgWhite}}, // White borders
        Separator: renderer.Tint{FG: renderer.Colors{color.FgWhite}}, // White separators
    }

    table := tablewriter.NewTable(os.Stdout,
        tablewriter.WithRenderer(renderer.NewColorized(colorCfg)),
        tablewriter.WithConfig(tablewriter.Config{
            Row: tw.CellConfig{
                Formatting:   tw.CellFormatting{AutoWrap: tw.WrapNormal}, // Wrap long content
                Alignment:    tw.CellAlignment{Global: tw.AlignLeft},     // Left-align rows
                ColMaxWidths: tw.CellWidth{Global: 25},
            },
            Footer: tw.CellConfig{
                Alignment: tw.CellAlignment{Global: tw.AlignRight},
            },
        }),
    )

    table.Header([]string{"ID", "Description", "Status"})
    table.Bulk(data)
    table.Footer([]string{"", "Total", "3"})
    table.Render()
}

Output (colors visible in ANSI-compatible terminals):

5. Streaming Table with Truncation

Stream a table incrementally with truncation and a footer, simulating a real-time data feed (inspired by TestOceanStreamTruncation and TestOceanStreamSlowOutput).

package main

import (
    "github.com/olekukonko/tablewriter"
    "github.com/olekukonko/tablewriter/tw"
    "log"
    "os"
    "time"
)

func main() {
    table := tablewriter.NewTable(os.Stdout, tablewriter.WithStreaming(tw.StreamConfig{Enable: true}))

    // Start streaming
    if err := table.Start(); err != nil {
        log.Fatalf("Start failed: %v", err)
    }

    defer table.Close()

    // Stream header
    table.Header([]string{"ID", "Description", "Status"})

    // Stream rows with simulated delay
    data := [][]string{
        {"1", "This description is too long", "OK"},
        {"2", "Short desc", "DONE"},
        {"3", "Another long description here", "ERROR"},
    }
    for _, row := range data {
        table.Append(row)
        time.Sleep(500 * time.Millisecond) // Simulate real-time data feed
    }

    // Stream footer
    table.Footer([]string{"", "Total", "3"})
}

Output (appears incrementally):

┌────────┬───────────────┬──────────┐
│   ID   │  DESCRIPTION  │  STATUS  │
├────────┼───────────────┼──────────┤
│ 1      │ This          │ OK       │
│        │ description   │          │
│        │ is too long   │          │
│ 2      │ Short desc    │ DONE     │
│ 3      │ Another long  │ ERROR    │
│        │ description   │          │
│        │ here          │          │
├────────┼───────────────┼──────────┤
│        │         Total │        3 │
└────────┴───────────────┴──────────┘

Note: Long descriptions are truncated with … due to fixed column widths. The output appears row-by-row, simulating a real-time feed.

6. Hierarchical Merging for Organizational Data

Show hierarchical merging for a tree-like structure, such as an organizational hierarchy (inspired by TestMergeHierarchicalUnicode).

```go package main

import ( "github.com/olekukonko/