Sherlock is live · free · last verified 26 Oct 2026 · viability monitor
Sherlock
Client-side JavaScript library that turns typed English date phrases into structured calendar events.
If you're building a form or chat input that needs to accept phrases like 'lunch on the 3rd' or 'retreat from Jan 12 - 29' and turn them into dates, Sherlock does that job in the browser with no server round-trip and no dependencies. The trade-off is scope: it is a rule-based English parser, so treat it as a convenience layer, not an authoritative scheduling engine. Teams needing timezone math, locale formatting, or multilingual input should pair it with a date library like date-fns or Luxon. Pick Sherlock when bundle size, privacy, and zero-dependency integration matter more than parsing breadth.
Verdict generatedVerified 10d ago · liveness 59/100 · cite: rightaichoice.com/tools/sherlock
- JavaScript developers adding date parsing to a web app
- Product teams building scheduling or reminder inputs
- Hobbyist developers building personal assistant tools
- Projects with strict bundle-size budgets
- Apps requiring timezone conversion
- Teams needing multilingual date parsing
- Non-developers wanting a finished calendar product
We scan live Reddit threads, YouTube comments, X posts, G2 reviews and other communities — and hand you an honest verdict in under a minute.
- Honest verdict, not marketing
- Real pros & cons from real users
- Attributed quotes with receipts
3 free scans · no card needed
Skip Sherlock if you need timezone conversion, multilingual parsing, or server-side accuracy guarantees — its rule-based English parser runs entirely in the browser and no maintainer SLA stands behind it.
The library itself is MIT-licensed with no fees, but if parsing accuracy matters to paying customers you will spend engineering hours maintaining or forking the ruleset yourself.
Sherlock is free and MIT licensed, which puts it at the bottom of the cost scale for natural-language date parsing. Hosted NL-date APIs typically charge per request and route typed text off-device; Sherlock costs nothing per call but covers only English and no timezone math. For a solo developer or a startup shipping a scheduling input, that trade is usually worth taking; for an enterprise that needs SLA-backed accuracy across locales, the free option is the wrong axis to optimize on.
In short
Sherlock — Client-side JavaScript library that turns typed English date phrases into structured calendar events. Best for JavaScript developers adding date parsing to a web app, Product teams building scheduling or reminder inputs, Hobbyist developers building personal assistant tools. Free to use.
What is Sherlock?
Sherlock — Client-side JavaScript library that turns typed English date phrases into structured calendar events. Best for JavaScript developers adding date parsing to a web app, Product teams building scheduling or reminder inputs, Hobbyist developers building personal assistant tools. Free to use.
Sherlock is a small open-source JavaScript library that converts typed English date and time phrases — 'next Monday at 3pm', 'The retreat is from Jan 12 - 29', 'Vacation is in 4 weeks' — into structured event data, entirely in the browser. A live demo on the project homepage lists exactly the kinds of inputs it targets: 'February 24 at 3pm - 2pm', 'Homework 5 due next monday at 3pm', 'Christmas is on December 25th', 'Let's have lunch on the 3rd', 'Bake a cake tomorrow'. Each returns an extracted event title plus start and end dates. Parsing is rule-based and runs locally, so there are no network calls and no API keys. The library ships with zero external dependencies and a minified build under 10KB, and it is MIT licensed with source on GitHub, so you can read the parsing rules, fork them, or contribute. It is deliberately narrow: event extraction from English text, not calendar management. The audience is developers, not end users.
Key features
- Parse natural language phrases into structured event data
- Extract event titles from free text
- Relative date support (e.g., "in 4 weeks", "tomorrow")
- Time range parsing (e.g., "from Jan 12 - 29")
- Holiday name recognition (e.g., "Christmas is on December 25th")
- Recurring event support (e.g., "every week")
- Ordinal day-of-month parsing (e.g., "on the 3rd")
- Extracts start and end dates from a single sentence
- Client-side processing with no server calls
- Zero external dependencies
- Minified bundle under 10KB
- MIT open-source license with source on GitHub
- English-language input
- Browser-based demo for testing phrases
- Works without network access
Behind the verdict
Sherlock's pitch is narrow and honest, and that is the point. The homepage demo shows the exact phrasings the maintainer intends to support: an explicit clock range ('February 24 at 3pm - 2pm'), a relative future date ('Vacation is in 4 weeks'), a named holiday with a date ('Christmas is on December 25th'), a titled event with a relative day and time ('Homework 5 due next monday at 3pm'), an ordinal day-of-month ('Let's have lunch on the 3rd'), a multi-day range ('The retreat is from Jan 12 - 29'), and a bare relative day ('Bake a cake tomorrow'). All of that runs client-side with zero external dependencies and a minified build under 10KB — which matters if you are shipping a scheduling input inside an existing bundle and cannot justify a parser that costs more than the rest of your app. Strengths: the dependency count and bundle size are the headline. No API keys, nothing leaves the browser, so privacy-sensitive apps that cannot send typed text to a third-party NLP service have a workable path. Event title extraction is a first-class output, not an afterthought, which is what distinguishes this from a plain date-formatter: you get a title plus start and end. Weaknesses and where it does not fit: it is English-only, it does not do timezone conversion, and it does not store events, detect conflicts, or fire reminders. Ambiguous input is a known soft spot because the ruleset is finite. It is also a single-maintainer open-source project, so you are depending on volunteer maintenance rather than a vendor SLA — factor that into anything customer-facing. The practical pattern is to use Sherlock as the NL front door and hand its structured output to a real date library (date-fns or Luxon) for timezone, locale, and arithmetic. That combination costs you almost nothing in bytes, keeps the user's text on-device, and covers the majority of the casual phrasings people actually type into scheduling inputs.
Limitations
- Sherlock is a rule-based, client-side date parser for English text, not an AI model.
- It handles common event phrasings — titled events, relative dates, explicit ranges, recurring patterns, ordinal days like "the 3rd", and holiday names — but ambiguous or complex date/time constructs may not resolve.
- It does not perform timezone conversion and does not provide calendar management such as storage, conflict detection, or reminders.
- Input coverage is English-only.
- Because it is a small single-maintainer open-source project, ongoing maintenance and feature velocity are not guaranteed the way a funded product's would be.
as of 2026-10-09
Researching Sherlock? Get your full AI stack in 60 seconds.
Free, no signup — tell us your goal and get tools matched to your budget & existing stack.
Is Sherlock still active?
Sherlock is live · free · last verified 26 Oct 2026 · viability monitor.
Viability score
How well maintained and how widely used is Sherlock? Built from what the vendor actually publishes (docs, changelog, tutorials, integrations, pricing), whether the site is live, and how much real users discuss it. How we calculate this
Last calculated: November 2026
How we score →What do users say about Sherlock?
What people actually say about Sherlock — is it worth it?
We scanned public community sources for Sherlock on Aug 14, 2026 and could not establish that the discussion we found is about this tool rather than something else sharing its name. Our own analysis of that scan says the posts were off-subject. Rather than publish a sentiment score built on the wrong subject, we publish nothing here and re-run the scan.
How we verified this
Every listed fact about Sherlock — pricing, features, links, status — is re-read from the vendor's own pages by our verification pipeline and each change is logged with a date; the last pass ran on 26 Oct 2026. Analysis is drafted with AI models and checked against our editorial standards before publishing; see how we verify.
Verification history
We have re-verified Sherlock 10 times since . Each pass re-reads the vendor's own pages and re-checks every listed field against that evidence; passes where nothing had changed are marked as such.
- — changed SSL certificate
- — changed description, who it suits, our verdict, features, hidden costs, limitations, switching in, switching out, pricing tiers, pricing fit, setup time, who should skip it, summary, use cases
- — changed switching in, who it suits, switching out, who should skip it, description, setup time, our verdict, features, summary, hidden costs, limitations, pricing tiers, pricing fit, use cases
- — changed SSL certificate
- — changed limitations
- — changed SSL certificate
Showing the 6 most recent of 10 verification passes.
Free to cite with attribution — this page re-verifies continuously.
How much does Sherlock cost in 2026?
Sherlock: Free to use. Pricing last verified 26 Oct 2026.
Plans compared
Every published Sherlock tier, its price as the vendor publishes it, who it fits, and what it adds over the tier below. The 12-month cost projection follows.
| Plan | Price | Billing | Who it's for |
|---|---|---|---|
| Open Source (MIT) | Free | — | JavaScript developers and small product teams who need client-side English date parsing and are comfortable self-supporting an open-source dependency.Adds: Starting tier: MIT-licensed source with no fees, zero external dependencies, and a minified build under 10KB. |
12-month cost
Project the real annual outlay, including the implied monthly cost when only an annual tier is published.
Vendor list price only. Add-on usage, seat overages, and contract minimums are surfaced under Hidden costs & gotchas.
Where the pricing makes sense
The company stage and team size where Sherlock's pricing actually pencils out — and where peers do it cheaper.
Sherlock is free and MIT licensed, which puts it at the bottom of the cost scale for natural-language date parsing. Hosted NL-date APIs typically charge per request and route typed text off-device; Sherlock costs nothing per call but covers only English and no timezone math. For a solo developer or a startup shipping a scheduling input, that trade is usually worth taking; for an enterprise that needs SLA-backed accuracy across locales, the free option is the wrong axis to optimize on.
Has Sherlock's pricing changed?
No plan price for Sherlock has moved since we began logging in Aug 2026; the pricing page is re-read on every verification pass.
Who should pick Sherlock?
Pick Sherlock if you are JavaScript developers adding date parsing to a web app, Product teams building scheduling or reminder inputs, Hobbyist developers building personal assistant tools, Projects with strict bundle-size budgets.
Look elsewhere if you are Apps requiring timezone conversion, Teams needing multilingual date parsing, Non-developers wanting a finished calendar product, Products requiring high-accuracy parsing of ambiguous input.
Skip it if Skip Sherlock if you need timezone conversion, multilingual parsing, or server-side accuracy guarantees — its rule-based English parser runs entirely in the browser and no maintainer SLA stands behind it.
GeneratedReal-world workflow fit
Concrete scenarios for the personas Sherlock actually fits — and what changes day-one when you adopt it.
You drop the minified Sherlock build into an existing React form so users can type "Design review next monday at 3pm" instead of filling four separate date pickers.
Outcome: Sherlock returns the title and start/end dates client-side; you pass the dates to date-fns for formatting and store them in your own backend.
Your users dictate or type reminders like "Bake a cake tomorrow" and "Vacation is in 4 weeks", and your policy forbids sending that text to a third-party NLP service.
Outcome: All parsing happens in the browser with no network call, so the raw text never leaves the device and no API key ever ships in your bundle.
Messages in your app mention things like "The retreat is from Jan 12 - 29" or "Christmas is on December 25th", and you want them turned into structured entries automatically.
Outcome: Sherlock extracts the title and the start and end dates from the sentence, and you persist them into whatever store you already use.
Use cases
- Turn a typed phrase like "meeting next Tuesday at 2pm" into a structured calendar event
- Add natural language date entry to a form or chat-style scheduling input
- Extract event title and dates from free text in a messaging app
- Power dictation or voice-transcribed commands that create calendar entries
- Convert free-text ranges like "from Jan 12 - 29" into start and end dates for booking flows
- Prototype scheduling features without standing up a parsing server
Setup time & first value
How long it actually takes to get something useful out of Sherlock — broken out by persona, not the marketing-page minute.
For a JavaScript developer: minutes. Add the sub-10KB script tag or npm install, call the parse function on a string, and read the returned event object — the homepage demo shows testable phrases you can use to sanity-check output before wiring it in. Budget an extra hour or two if you also need to bolt on date-fns or Luxon for timezone and formatting, since Sherlock deliberately stops at
Switching to or from Sherlock
How to bring data in from common predecessors and how to get it back out — written for the switcher, not the buyer.
- →From a hosted natural-language date API: route the same typed input through Sherlock locally, then reconcile the date strings your downstream code already expects.
- →From hand-written regex date parsing: replace your pattern list with Sherlock's rule-based parser and keep your existing event-storage code unchanged.
- →From a general date library alone: keep date-fns or Luxon for formatting and arithmetic, and let Sherlock handle the natural-language front end.
- ↗To a hosted NL date API: if you need multilingual or higher-accuracy parsing, swap the local parse call for an HTTP request and accept per-call cost and off-device text.
- ↗To date-fns or Luxon alone: if your inputs are already structured, drop the parser layer and format the dates directly.
- ↗To a full calendar product: if you need storage, conflict detection, and reminders, Sherlock was never the layer that handled those.
Tutorials & Learning
YouTube returned 6 videos for “Sherlock”, and we withheld 6: 6 could not be judged, because “Sherlock” is a single word that other videos use for other things. We are showing none, because we could not prove any of them are about Sherlock.
Official links
What are the best Sherlock alternatives?
The closest alternatives to Sherlock we list are Voiset, Vimcal and Agenda Hero Magic. Ranked by direct product-type match, not category overlap.
| Alternative | Pricing | Starts at | Last verified |
|---|---|---|---|
| Voiset | Freemium | Pricing not published | — |
| Vimcal | Freemium | Pricing not published | — |
| Agenda Hero Magic | Freemium | Pricing not published | — |
Alternatives to Sherlock
View all
Voiset
Voiset is a voice-first AI calendar that turns spoken tasks into a scheduled, prioritized day plan.
Vimcal
Vimcal is a keyboard-first AI calendar that books meetings from typed availability instead of booking links.
Agenda Hero Magic
Turn text, PDFs, images, and forwarded email into calendar events with Agenda Hero Magic.
Tools that pair well with Sherlock
Common stack mates teams adopt alongside Sherlock, with the specific reason each pairing earns its keep.
Voiset
Voiset is a voice-first AI calendar that turns spoken tasks into a scheduled, prioritized day plan.
Vimcal
Vimcal is a keyboard-first AI calendar that books meetings from typed availability instead of booking links.
Agenda Hero Magic
Turn text, PDFs, images, and forwarded email into calendar events with Agenda Hero Magic.
Sherlock vs its closest rival
Sherlock's closest head-to-head is with Bito.
Our Sherlock vs Bito verdict written Jul 6, 2026 is more than 90 days old, so it is being re-reviewed against current data and is not shown.
Head-to-head comparisons
Frequently asked questions
Categories
Topics
For makers of Sherlock
- Get a Verified Listing for Sherlock ($39): a written decision within 1 working day.
- Free listing for another tool: Free reviews are decided in order, within 3 weeks.
Used Sherlock? Help shape our editorial sentiment research.