MongoDB ObjectId

Client

A BSON ObjectId is 12 bytes shown as 24 hex digits: four-byte big-endian Unix time, three-byte machine id, two-byte process id, and a three-byte counter. Parse existing ids or generate new ones locally—useful next to JSON ↔ BSON and time tools.

Related tools

Compare time ordering with ULID and UUID v7. Convert the embedded second with the Unix timestamp workspace for time zones and ISO strings.

Parse ObjectId

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12-byte BSON value: Unix time (seconds) in the first four bytes (big-endian), then random/process fields—useful for rough document age, not a cryptographic guarantee.

Generate ObjectIds

Uses current Unix second plus eight random bytes—same 12-byte shape as MongoDB drivers for client-generated ids.

  • 69eb4f5e867a53cbbf83aa2d
  • 69eb4f5ea15b0e374d425cff
  • 69eb4f5e856d21e882434908
  • 69eb4f5e45160cd525398f2c
  • 69eb4f5e7a21c5d8ed63adc0

Common use cases

  • Read the embedded creation time from a log line or support ticket id without opening a database shell.
  • Generate placeholder ObjectIds for fixtures and API mocks that match the hex shape your UI expects.
  • Compare ObjectId timestamps with ULID or UUID v7 when choosing sortable identifiers for a new service.
  • Cross-check BSON JSON ↔ BSON conversion against the separate ObjectId field format in docs.

Common mistakes to avoid

  • Treating the timestamp as authoritative audit evidence

    Clock skew, imported data, and manually set values can make the first four bytes misleading—verify with application metadata when it matters.

  • Assuming machine and pid map to real hosts

    Drivers hash randomness into these fields; treat them as opaque entropy unless you control the generator.

  • Forgetting endianness when reading raw bytes

    ObjectId uses big-endian for the 32-bit timestamp and 16-bit process id—this page matches the wire order MongoDB uses.

FAQ

Is this the same as MongoDB’s server ObjectId?

Layout matches the 12-byte BSON type. Values generated here use the current second plus random trailing bytes, like typical client drivers—not the exact server monotonic counter.

Can I paste Extended JSON like {"$oid": "…"}?

Strip to the 24 hex characters (or use ?q= with the hex). This page does not parse full EJSON wrappers.

Prefill from a URL?

Yes—?q= or ?qb= fills the parse field with hex text.

Common search terms

Phrases people search for that match this tool. See the full long-tail keyword index.

  • mongodb objectid parser online
  • decode objectid timestamp hex 24
  • generate objectid browser local
  • bson objectid machine pid counter

More tools

Related utilities you can open in another tab—mostly client-side.