Anywhere Door hops
Every short code opens straight onto its long URL — one click, no maze. Deep links resolve locally and count a bell-ring on arrival.
Fresh from the 4D pocket · gadget-powered links
An Anywhere Door
for your links.
Step through with any long URL and come out the other side with a short one — Snowflake IDs, Base62 codes, Memory-Bread dedup and Time-Furoshiki expiry. Dorayaki optional, delight guaranteed.
- Anywhere Door
- Instant hops
- Memory Bread
- Smart dedup
- Time Furoshiki
- Honest expiry
Got a long link? Shrink it with the Small Light.
https://example.com/a/very/long/path/you-do-not-want-to-sharedora.ly/7chars
Snowflake IDs · Base62 · Furoshiki TTL · Pocket guard — shareable anywhere
Gadget shelf — the lineup
Four gadgets, zero filler.
Memory Bread dedup
Feed the lab a URL it has already memorized and it recalls the same code instead of minting a twin. One URL, one name — like it studied overnight.
Time Furoshiki expiry
Wrap a link in a TTL and it ages exactly on schedule. Record and cache share the same lifetime, so nothing lingers past its time.
4D Pocket guard
A 1M-entry Bloom filter fronts the store: unknown codes are turned away at the pocket mouth, and every claimed hit is verified inside.
Inside the pocket — the method
Four small steps through the Door.
- 01
Snowflake ID
Sewn by the Time Furoshiki
(ts − epoch) << 22 | worker << 12 | seq
A 64-bit, time-ordered identity. Worker IDs are range-checked 0–1023, the clock is guarded against moving backwards, and 16k concurrent IDs stay unique.
- 02
Base62 code
Folded pocket-size
encode(id) → [0-9A-Za-z]
BigInt-safe encoding — never Number — so large IDs keep their precision. Auto codes take the last 7 characters with retry-on-collision.
- 03
Alias or mint
Named with Memory Bread
alias ? reserve : generate
Your gadget name is validated and reserved behind a uniqueness check; duplicates raise a conflict instead of silently overwriting.
- 04
Store, cache, pocket
Filed in the 4D Pocket
record + ttl cache + bloom.put(code)
The record carries createdAt and expiresAt; the cache TTL mirrors it exactly. The Bloom filter learns each code for cheap negative lookups.
Pocket rules — lessons, kept
Ten compiler scoldings, five design traps — now house rules.
Every rule below was earned debugging the original Java service. They hang by the Door so the lab never repeats them.
Check the worker's badge
Ten bits means 0–1023. Anything else is turned away at the Door — never silently overflows into the timestamp.
No time travel
If the clock moves backwards, ID minting stops instead of duplicating. Doraemon respects the timeline.
Never fold blindly
Careless truncation destroyed uniqueness and could crash. Full codes by default; shortened only with collision retries.
Cache what you promise
The cache TTL is cut from the same Furoshiki as the record — no stale ghosts lingering after expiry.
Asked at the Door
Questions, answered kindly.
- In this browser's own little 4D pocket (localStorage) — no account, no tracking. In production the same service fronts a database with a UNIQUE constraint on the code plus a Redis cache.
- Seven Base62 characters give about 3.5 trillion combinations — short enough to say out loud, large enough to stay safe. Because folding raises collision risk, the lab retries with a fresh Snowflake ID whenever a code is taken.
- It wraps the link in a TTL: expiresAt on the record and the identical TTL on the cache entry. After unwrapping, the code shows an ‘expired’ notice instead of a stale redirect.
- A 1M-entry Bloom filter with ~1% false positives that answers ‘definitely never seen’ without touching the database. Claimed hits are always verified against the store — a guard, never the source of truth.
- Yes — 1–16 characters of letters, numbers, _ or -. Taken names raise a clear conflict so nothing is ever overwritten, the way Nobita's homework never should be.
The finale
Your Anywhere Door is waiting.
Push a long link through, name it like a gadget, and share something as delightful as where it leads.
Ring the bell