New: `ID()` — Fast, Human-Readable Random Identifier

(GoFakeIt v7.9.0)

gofakeit.ID() is a new high-performance identifier generator designed for speed, readability, and practically zero collision probability.

Unlike UUID v4 or XID, this generator is intentionally random-first, not structure-based.
Perfect for mock APIs, test data, fixtures, seed data, and temporary identifiers.

Highlights

Human readable alphabet, no confusing characters
→ 23456789abcdefghjkmnpqrstuvwxyz (no 1, l, i or 0, o to alleviate confusion)
Fast
Memory Allocation
Generates from your rand source
Shorter than UUID, faster than XID, and requires no coordination

Example

id := gofakeit.ID()
fmt.Println(id)
// → "3t9qf4c92npxhw7bg6y0"

Performance Benchmarks

Measured on Go 1.25

Generator / Function	Benchmark Name	ops/sec	ns/op	B/op	allocs/op
`gofakeit.ID()`	BenchmarkID-10	31,383,146	37.8 ns	24	1
`gofakeit.UUIDv4()`	BenchmarkUUIDv4-10	22,131,577	53.8 ns	48	1
`github.com/rs/xid`	BenchmarkXID-10	16,190,817	74.2 ns	0	0
`github.com/google/uuid` (v4)	BenchmarkGoogleUUIDv4-10	3,098,770	386.1 ns	64	2

Takeaway: gofakeit.ID() is ~2× faster than XID and ~10× faster than UUID v4, while being shorter and human-readable.

Collision Probability (Randomness Math)

ID length: 20 characters
Alphabet: 32 slots with one duplicated character (intentional) → avoids retries, maximizes speed
Effective entropy: ≈ 98.25 bits

Even under very large bursts, duplication is astronomically unlikely

Collision probability when generating `n` IDs within 1 second (birthday bound)

n (IDs in 1s)	`gofakeit.ID()` collision probability
100,000	0.00000000000000000001326
1,000,000	0.000000000000000001326017
10,000,000	0.000000000000000132601736
100,000,000	0.000000000000013260173678
1,000,000,000	0.000000000001326017367838

For comparison (same n):

UUID v4 (122 bits): much lower probabilities (but significantly slower and longer)
XID: structural uniqueness (time + machine + pid + counter). Treat collisions as operationally zero when configured normally.

Need structural, sortable IDs? Use XID or Snowflake.
Want random, readable, fast? Use gofakeit.ID().

RNG Behavior

Mode	Behavior
Default (`gofakeit.ID()`)	PCG for speed, seeded via crypto/rand → fast + unpredictable
Full crypto (`NewFaker(source.NewCrypto())`)	crypto/rand for every ID → maximum randomness (slower)
Deterministic (`New(seed)`)	PCG with fixed seed → reproducible ID sequences (useful for tests/fixtures)

We seed PCG with a cryptographic seed when seed == 0. This prevents accidental identical streams across processes/containers.

Example Usage

package main

import (
	"fmt"

	"github.com/brianvoe/gofakeit/v7"
	"github.com/brianvoe/gofakeit/v7/source"
)

func main() {
	// Fast ID — PCG, automatically crypto-seeded
	fmt.Println("fast ID:", gofakeit.ID())

	// Cryptographically secure per-ID RNG
	crypto := source.NewCrypto()
	faker := gofakeit.NewFaker(crypto, true)
	fmt.Println("crypto ID:", faker.ID())
}

brianvoe/gofakeit v7.9.0 ID Generator on GitHub

New: ID() — Fast, Human-Readable Random Identifier