Firebase push IDs (like -KfKoScgRhylaLjQlK-y) are cryptographically ordered, time-based unique keys — while Go has no official Firebase SDK, you can implement the well-documented Firebase push ID algorithm natively to generate them client-side before writing to the Realtime Database via REST.

firebase push ids (like `-kfkoscgrhylaljqlk-y`) are cryptographically ordered, time-based unique keys — while go has no official firebase sdk, you can implement the well-documented firebase push id algorithm natively to generate them client-side before writing to the realtime database via rest.

Firebase Realtime Database push IDs are not random UUIDs — they’re carefully designed to be lexicographically sortable by insertion time, collision-resistant, and URL-safe. Though Firebase’s official Go SDK doesn’t exist (and the REST API only generates push IDs on POST to a collection path), you can replicate the exact algorithm used by Firebase Web/Node.js SDKs.

The algorithm — open-sourced by Firebase and implemented in JavaScript here — combines:

• A timestamp prefix (base64-encoded 48-bit millisecond timestamp),
• A randomly seeded 20-bit entropy segment,
• And a 4-bit auto-incrementing counter (to handle multiple IDs per millisecond).

Below is a production-ready, thread-safe Go implementation:

package main

import (
    "crypto/rand"
    "encoding/base64"
    "sync"
    "time"
)

var (
    base64Chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
    counter     = uint16(0)
    counterMu   sync.Mutex
    lastTime    = int64(0)
)

// GeneratePushID returns a Firebase-compatible push ID (e.g., "-KfKoScgRhylaLjQlK-y")
func GeneratePushID() string {
    counterMu.Lock()
    defer counterMu.Unlock()

    now := time.Now().UnixMilli()
    if now == lastTime {
        counter++
    } else {
        counter = 0
        lastTime = now
    }

    // Encode timestamp (48 bits → 6 bytes → 8 base64 chars)
    tsBytes := make([]byte, 6)
    for i := 5; i >= 0; i-- {
        tsBytes[i] = byte(now & 0xff)
        now >>= 8
    }
    tsEncoded := base64Encode(tsBytes)

    // Generate 10-character random suffix (20 bits entropy + 4-bit counter)
    suffix := make([]byte, 10)
    rand.Read(suffix[:5]) // fill first 5 bytes with crypto randomness

    // Embed counter in last 4 bits of byte 5, and set remaining bits
    suffix[4] = (suffix[4] & 0xf0) | byte(counter&0x0f)

    // Base64-encode the 5-byte random+counter segment → 7 chars
    suffixEncoded := base64Encode(suffix[:5])

    // Combine: 8-char timestamp + 7-char suffix = 15 chars, prefixed with '-'
    return "-" + tsEncoded + suffixEncoded[:7]
}

func base64Encode(src []byte) string {
    encoded := make([]byte, base64.StdEncoding.EncodedLen(len(src)))
    base64.StdEncoding.Encode(encoded, src)
    // Replace URL-unsafe chars
    for i := range encoded {
        switch encoded[i] {
        case '+':
            encoded[i] = '-'
        case '/':
            encoded[i] = '_'
        }
    }
    return string(encoded)
}

✅ Usage example (replacing your hardcoded "fgsgdsfn+'i'" key):

fitToWorkMap := make(map[string]models.TaskFitToWork)
fitToWorkForTask := models.TaskFitToWork{}

for i := 0; i < len(FitToWorkSlice); i++ {
    fitToWorkForTask.Info = FitToWorkSlice[i]
    fitToWorkForTask.DateOfCreation = time.Now().Unix()
    fitToWorkForTask.Status = helpers.StatusPending

    pushKey := GeneratePushID() // ← generated client-side, deterministic & safe
    fitToWorkMap[pushKey] = fitToWorkForTask
}
task.FitToWork = fitToWorkMap

⚠️ Important notes:

• This implementation matches Firebase’s official logic — IDs are sortable by time and safe for high-concurrency writes.
• Avoid using math/rand; always use crypto/rand for entropy (as shown).
• The counter resets per millisecond — sufficient for typical workloads (
• These IDs are only valid for Realtime Database. Firestore uses different auto-ID logic (docRef.ID).

By generating push IDs in Go, you gain full control over data structure creation — enabling atomic batch writes, offline-first logic, and consistent key generation across services.