BASICFree
General server-time checks
- Low request volume
- Core sample validation
- 30-minute session
WINDOWS 10 / 11 · x64
Measure the time a server reports
with more care.
DongClock Server Time does not treat a single HTTP response as ground truth. It compares round-trip time and consistency across multiple observations to estimate server time within the information HTTP can actually provide.
A Windows tool that estimates server time from repeated HTTP responses and network timing.
Pro: one-time $7 payment · one year from purchase · no automatic renewal
HTTP TIME OBSERVATIONMEASURING
SERVER ESTIMATE · KST
14:42:28.482
advancing from a monotonic anchor
ROUND TRIPMeasure
SAMPLESCompare
RESULTDisplay after validation
Start with a possible offset interval, not a single exact point.
01 Never trust one response blindly
02 Avoid false confidence
03 Avoid sustained high-frequency requests
04 Be honest about HTTP Date limitations
QUICK CHOICE
Free Basic or
deeper Pro
Choose an edition first, then open the technical detail only when you need it.
PRO$7 / 1 year
More conservative validation
- Advanced state decisions
- Denser rechecks
- No session limit
Compare Basic / Pro in detail
- Basic: stable estimation for general use, baseline response checks, and server-friendly revalidation
- Pro: more initial evidence, path and timing separation, stronger cache defenses, and additional checks for large changes
- Both: Windows 10 / 11 x64 with Portable and Installer formats
License and delivery details
- Pro is a one-time $7 payment, valid for one year, with no automatic renewal
- Gumroad License Key, initial online activation, and periodic revalidation
- Current builds are not Authenticode-signed, so SmartScreen may warn
MEASUREMENT / 01
Follow the measurement flow,
not a single response.
DongClock observes the HTTP time sent by the server together with network round-trip time, then displays an estimate only after multiple measurements are consistent.
- Read HTTP Date with round-trip time
- Compare consistency across measurements
- Exclude suspicious responses
See the measurement flow
- Enter a website address
- Send HTTP request and receive server time
- Observe network round-trip time
- Compare results and exclude anomalies
- Estimate a consistent server time
HTTP Date usually has one-second resolution, and one-way network delay cannot be observed directly.
- 01Enter a websiteChoose an HTTP or HTTPS target.
- 02Send HTTP requestAsk the target server for a response.
- 03Receive server timeRead the response Date information.
- 04Measure round tripObserve the time taken by request and response.
- 05Compare measurementsDo not treat one response as ground truth.
- 06Exclude anomaliesSeparate suspicious latency, cache, and response behavior.
- 07Estimate server timeDisplay a result when the remaining evidence agrees.
A little more technical detail
HTTP Date usually has one-second resolution, and one-way network delay cannot be observed directly. DongClock uses possible time ranges and agreement across observations without presenting internal formulas or thresholds as an accuracy guarantee.
VALIDATION / 02
Prefer honest uncertainty
over a smaller number.
A new observation does not automatically replace the current estimate. DongClock also checks response structure and continuity.
- Check RTT and sample agreement
- Separate cache and stale responses
- Require more evidence for large changes
See validation principles
- Separate abnormal RTT and observations that do not agree.
- Check repeated, non-advancing, or regressing Date behavior.
- Advance a validated basis from the PC's monotonic clock.
DongClock does not invent information HTTP never provided.
RTT & consensus
Observations beyond robust RTT limits are filtered, and only sufficiently agreeing intervals contribute to the estimate.
Cache & stale checks
Explicit cache responses, repeated non-advancing dates, and Date regression are treated as distinct warning signals.
Conservative changes
Large offset changes need additional consistent evidence. Pro applies precision candidates only after layered checks pass.
Monotonic anchor
A validated offset advances from the PC's monotonic clock instead of rebuilding time from the operating-system wall clock every frame.
CORE PRINCIPLE
DongClock does not invent information HTTP never provided.
It is designed to avoid premature conclusions with the evidence that is available.
SERVER-FRIENDLY / 03
Server-friendly
by design.
Measure when needed, then reduce request frequency when stable.
DongClock gathers baseline evidence first, relaxes the interval when stable, and waits longer after errors or rate-limit responses.
- Measure first to build a baseline
- Increase intervals after stability
- Wait longer after errors or rate limits
HTTP measurement cannot create zero load. Please check the target service's terms and permitted use.
See request-policy detail
Basic prioritizes low request volume; Pro prioritizes more evidence and faster rechecks. Both reduce request frequency after the target becomes stable.
HTTP traffic cannot create zero load. Check the target service's terms and permitted use.
ADAPTIVE REQUEST POLICYShorter intervals mean more frequent checks
BasicLow-load measurement
AcquisitionBaseline evidenceLightweight start
UnstableRecheck as neededInterval adapts to state
StableLower request rateMore relaxed when stable
ProDenser measurement
AcquisitionMore evidenceDenser than Basic
UnstableFaster rechecksConservative validation
StableCloser monitoringLong-running measurement
Pro measures relatively more often. Basic prioritizes low request volume; Pro prioritizes more evidence and faster rechecks. Both reduce request frequency after the target becomes stable.
Repeated 403 · 429 · 503 · consecutive failures→ increase interval
- 1Normal measurementCollect observations
and estimate time - 2Sleep · long pauseMeasurement
continuity is lost - 3Measure againExclude old evidence
and start fresh
CONTINUITY / 04
After sleep, do not blindly continue
the previous estimate.After a long pause,
check again.
After sleep or a long interruption, old observations may no longer represent the current server path. DongClock does not mix that evidence into the new measurement; it builds a fresh basis from new observations.
After sleep or a long interruption, DongClock discards the old timing basis and checks again with fresh observations.
Technical detail
If the scheduled measurement is delayed beyond an allowed range, or PC clock continuity becomes unreliable, the prior estimator state is cleared and measurement restarts from fresh observations. Session identity and cumulative statistics remain, but old consensus evidence does not carry forward.
See technical detail
- Normal measurement
- Sleep or a long pause breaks continuity
- Exclude old evidence and measure again
The session and cumulative statistics remain, but old consensus evidence does not carry forward.
CHOOSE YOUR EDITION
Choose the measurement style you need
Basic is designed for general use and low request volume. Pro supports longer observation and more conservative precision-candidate handling.
BASIC
Freeno charge
Lightweight, stable
server-time checks
- Baseline validation for general use
- Low-request adaptive measurement policy
- RTT, consensus, cache, stale, and regression checks
- 30-minute measurement session
- Windows 10 / 11 x64
Windows 10 / 11 x64
1-YEAR LICENSE
PRO
$71-year license
Longer observation,
conservative precision
- More initial evidence · no session time limit
- Denser checks and faster revalidation
- Stronger cache defenses and response analysis
- Separates differing response paths and timing behavior
- Applies precision candidates only after sufficient consistency
One-time payment · no automatic renewal
| Feature | Basic | Pro |
|---|---|---|
| Price | Free | $7 · one year from purchase |
| Initial check | Baseline evidence | More evidence |
| Measurement | Stable estimate for general use | Validated precision candidates |
| Response analysis | Baseline validation | Finer path and timing separation |
| Session | 30 minutes | No time limit |
| Cache policy | Server-friendly revalidation | Stronger cache defense |
PURCHASE & DELIVERY
What to know before purchase
One year from purchase
Pro is a one-time $7 payment, not a subscription or automatic renewal. It uses a Gumroad License Key.
- Internet required for first activation
- Periodic license revalidation afterward
- Limited grace period for temporary connection failures
Portable and Installer
Both formats are provided for Windows 10 / 11 x64.
- Portable: run without installation
- Installer: standard Windows installation
Current builds are not code-signed
Current Windows builds do not have an Authenticode code signature, so SmartScreen may show a warning. Verify the official link and file name before running the app.
ACCURACY & LIMITS / 05
Be honest
about accuracy.
DongClock is not an atomic clock, NTP client, or PTP instrument.
01
HTTP Date normally has one-second resolution. Displayed milliseconds come from interval agreement and monotonic progression, not from a millisecond timestamp supplied by the server.
02
One-way delay cannot be observed directly. Request and response paths may be asymmetric.
03
The server clock itself may be wrong. Internal consistency cannot certify absolute agreement with true UTC.
04
An intermediary may generate Date. DongClock does not claim perfect proxy, CDN, or differing-backend identification.
05
Read the full Accuracy & Limitations notice →No fixed ±X ms guarantee. Results depend on the server, network, cache behavior, and path.
PRACTICAL USE
A tool for observing time
Ticketing and reservation server timeWeb-service event start timesWeb-server Date header comparisonServer response timing observation
DongClock measures and displays time. It does not provide automatic clicking or purchase automation.
WINDOWS APP / 06
The interface and measurement engine
have separate responsibilities.
DongClock is a Tauri 2 application for Windows x64. The interface handles input and presentation; the Rust engine owns network requests, measurement state, validation, and adaptive scheduling.
See app architecture
- WebView UI: address input, settings, and status
- Rust engine: HTTP probes, interval estimation, and validation
- Network guard: blocks local/reserved targets and revalidates redirects
UI
WebView interfaceServer address, settings, measurement state, and time display.
CORE
Rust measurement engineHTTP probes, interval estimation, validation, and the monotonic anchor.
GUARD
Network safety checksAllows HTTP/HTTPS, blocks local and reserved targets, and revalidates every redirect.
FAQ / 07
Questions,
answered clearly.
Product behavior and purchase terms without hidden claims.
Is DongClock an NTP program?
No. DongClock observes the target web server's HTTP Date header. It does not use standard NTP/PTP measurement or an external atomic-clock reference.
How accurate is the server time?
There is no fixed ±X ms guarantee. Results depend on HTTP Date resolution, network asymmetry, server and CDN clocks, and cache behavior. DongClock uses agreement and validation to avoid premature conclusions within those limits.
Why make multiple requests?
One Date response describes only a possible offset interval. Multiple intervals and RTT observations are needed to identify a consistent range and distinguish abnormal samples.
Does it burden the server?
Any measurement creates HTTP requests. DongClock increases intervals after stability and backs off after errors or rate limiting to avoid sustained high-frequency polling.
What is the difference between Basic and Pro?
Basic is designed around a 30-minute session and low request volume. Pro has no session time limit, gathers more evidence, separates response paths and timing behavior more finely, and applies precision candidates only after sufficient validation.
Is Pro a subscription?
No. One $7 payment grants use for one year from the purchase date.
Is there automatic renewal or automatic billing?
No. Pro is not charged or renewed automatically after one year. To continue, you must purchase a new license yourself.
Does DongClock automate clicks or purchases?
No. DongClock measures and displays server time. It does not perform automatic clicking, reservations, or purchases.
What happens when Pro expires?
The Pro interface and license management remain available, but starting a new measurement is restricted. Existing data is not automatically deleted, and a new key can be entered after renewal.
Does Pro stop immediately when the internet disconnects?
No. A Gumroad License Key needs an online check for first activation and periodic revalidation. A temporary Gumroad outage has a grace period, bounded by the license expiry date.
Can Windows SmartScreen appear?
Yes. Current builds do not have an Authenticode code signature, so Windows SmartScreen may show a warning. Verify the official link and file name before running the app.
DOWNLOAD
Read the time a server sends
with more care.
Windows 10 / 11 x64 · DongClock Server Time 1.0.0
Portable (no install) and Installer provided · currently unsigned · SmartScreen warning possible
DongClock BasicFreeDownload FreePortable + Installer
DongClock Pro$7 / 1 yearBuy on Gumroad One-time payment · no automatic renewal · Portable + Installer