ChessMonitor + OpeningTree review: scores and evidence
ChessMonitor links Chess.com/Lichess or uploaded games to produce statistics, an opening explorer, a FIDE estimate and scouting, with a database of 10M OTB games and Stockfish 18; OpeningTree (GPL-3) builds the tree of your games for free. Neither offers exercises, courses or a diagnosis of named weaknesses.
Read on August 30, 2026 from the service’s public pages — every score cites the page read.
Overall score
2.3/ 10
Rank
74=/ 128
Languages
1
Listed price
Pro €538.80/yr (€59.90/mo); Plus €70.80/yr (€7.90/mo); OpeningTree free — read by hand on /pricing, 2026-09-01.
What the service is
This entry groups two independent services. ChessMonitor is published by ChessMonitor UG (haftungsbeschränkt), a German company in Eschweiler (register HRB 27657, Aachen) run by Thomas Dondorf (https://www.chessmonitor.com/legal); started in 2020 as a personal project with a prototype in 2021, it received the EXIST grant from the German Federal Ministry for Economic Affairs from March 2024 to February 2025 (https://www.chessmonitor.com/about; https://www.chessmonitor.com/blog/2024-chessmonitor-receives-startup-grant), and grandmaster Anish Giri became co-owner in October 2025. It links Chess.com and Lichess accounts or reads uploaded PGNs, produces opening and result statistics, an explorer with Stockfish 18, a FIDE rating estimate, opponent scouting and an "Ultra" database of 10 million over-the-board games updated live; iOS and Android apps since April 2026. Business model (https://www.chessmonitor.com/pricing): Basic free, Plus at €7.90/month, Professional at €59.90/month, no trial. OpeningTree (https://www.openingtree.com), open source under GPL-3.0 and free, builds the opening tree of your own games; Vanuj Juneja’s repository (https://github.com/openingtree/openingtree) was created in November 2019, its last release 6.4.0 dates from February 2022 and its latest commits from May 2026. Neither offers exercises, courses, a coach or a diagnosis of named weaknesses; English-only interfaces.
Activity history
- 2026-064 June 2026: transpositions handled in the explorer and broadcasts in beta; matching iOS version 1.3.6 on 11 June (https://www.chessmonitor.com/blog; https://apps.apple.com/us/app/chessmonitor/id6755627535).
- 2026-058 May 2026: the Masters database becomes the "Ultra Database" with live updates through the Lichess API, Stockfish 18 added to the web version, new homepage featuring Anish Giri (https://www.chessmonitor.com/blog/2026-ultra-database).
- 2026-0427 April 2026: release of the ChessMonitor mobile app for iPhone and Android (https://www.chessmonitor.com/blog/2026-chessmonitor-mobile-app).
- 2025-1019 October 2025: grandmaster Anish Giri joins ChessMonitor as co-owner and partner, with 50% of the shares announced (https://www.chessmonitor.com/blog/2025-anish-giri-joins-chessmonitor).
- 2025-019-10 January 2025: release of the Masters Database, PGNs collected from over 20 sources with monthly de-duplication (https://www.chessmonitor.com/changelog; https://www.chessmonitor.com/blog).
- 2024-0531 May 2024: ChessMonitor announces the EXIST grant from the German Federal Ministry for Economic Affairs, from March 2024 to February 2025, letting the founder work on it full time (https://www.chessmonitor.com/blog/2024-chessmonitor-receives-startup-grant).
- 2022-024 February 2022: OpeningTree 6.4.0, the last published release (Lichess login fixed, rating and time control corrected); occasional commits continue until May 2026 (https://github.com/openingtree/openingtree/releases; https://github.com/openingtree/openingtree/commits/master).
- 2020-0320 March 2020: OpeningTree 1.0.0, "First version to go live"; 6.0.0 on 29 November 2020 adds the opening book tab (https://github.com/openingtree/openingtree/releases).
The scores, evidence by evidence
Every score points to the page read and the fact found there. A fact documented nowhere is not credited: document it, then write to us.
APersonalized diagnosis
2.9A1 :3Importing your games (Chess.com, Lichess, PGN files)
https://www.chessmonitor.com/: "Link your Chess.com, Lichess accounts and upload own games"; https://raw.githubusercontent.com/openingtree/openingtree/master/README.md: PGN from any source
A2 :1Automatic engine analysis of every game
https://apps.apple.com/us/app/chessmonitor/id6755627535: "Stockfish 18 engine integration" in the explorer; no automatic analysis of every game documented
A3 :1Recurring mistakes identified across all your games
https://www.chessmonitor.com/ — opening and result statistics; no named mistake
A4 :0Types of mistakes covered (tactics, strategy, endgame, time…)
https://www.chessmonitor.com/ — no typology of mistakes
A5 :0Written explanation of each mistake
https://www.chessmonitor.com/ — no written explanation
A6 :0Stated verification of the diagnoses (procedure, rates)
no mention on https://www.chessmonitor.com/
A7 :1Tracking each weakness over time
https://www.chessmonitor.com/: "Estimate your FIDE Elo rating, track your progress" — rating curve
A8 :1Comparison with players of the same rating
https://www.chessmonitor.com/: FIDE rating estimate (position), no comparison by axis
BOpenings
2.8B1 :0Building a personal repertoire
https://raw.githubusercontent.com/openingtree/openingtree/master/README.md: tree built from games, no repertoire editor; https://www.chessmonitor.com/pricing: "custom database"
B2 :0Training the repertoire (drills, games)
no drill on https://www.chessmonitor.com/, https://raw.githubusercontent.com/openingtree/openingtree/master/README.md
B3 :1Spotting where you left your repertoire in your games
https://www.chessmonitor.com/pricing: "Opening Statistics" on your games; https://raw.githubusercontent.com/openingtree/openingtree/master/README.md: "win percentages and statistics"
B4 :0Verification of the lines taught (engine, practice)
no line verification on https://www.chessmonitor.com/
B5 :3Opening explorer and statistics
https://www.chessmonitor.com/: "10 million games" OTB + online games + your own games, Stockfish 18 (https://apps.apple.com/us/app/chessmonitor/id6755627535)
B6 :1Explanation of opening plans and ideas
https://www.chessmonitor.com/: opening names and statistics, no teaching
CTargeted training
0.0C1 :0Exercises drawn from your own games
no exercise on https://www.chessmonitor.com/
C2 :0Bank of tactical exercises (size, themes, rating)
no bank on https://www.chessmonitor.com/
C3 :0Endgame training
no endgame on https://www.chessmonitor.com/
C4 :0Strategic and positional training
https://www.chessmonitor.com/ — no exercise
C5 :0Training defense and alertness
https://www.chessmonitor.com/ — no exercise
C6 :0Training calculation and visualization
no calculation on https://www.chessmonitor.com/
C7 :0Difficulty matched to your real level
no adaptivity on https://www.chessmonitor.com/
C8 :0Spaced repetition (named algorithm)
https://www.chessmonitor.com/ — no spaced repetition
C9 :0Personalized training plan
https://www.chessmonitor.com/ — no plan
DPrice and value
3.3D1 :2What the free plan actually lets you do
https://www.chessmonitor.com/pricing: Basic "100% free" — one account per platform, "Single, limited custom database"
D2 :0Annual price of the full plan
https://www.chessmonitor.com/pricing — full Pro offer €538.80/yr (> €150 bracket); the Plus tier is €70.80/yr. Read by hand on 01/09/2026: amounts are only rendered with JavaScript.
D3 :0Commercial transparency (price shown, trial, cancellation)
https://www.chessmonitor.com/pricing: amounts not rendered without JavaScript (placeholders), "Cancel anytime", no trial
D4 :2Number of paid tiers (how simple the offer is)
https://www.chessmonitor.com/pricing — free Basic + two paid tiers (Plus, Professional); Professional unlocks everything
EEvidence and transparency
4.2E1 :0Published evidence of effectiveness
no data on https://www.chessmonitor.com/
E2 :0Chess verification of the content (positions, lines)
no information on https://www.chessmonitor.com/
E3 :3Transparency of the method (algorithms, code)
https://github.com/openingtree/openingtree: public GPL-3.0 code (474 stars, last push 03/05/2026); https://apps.apple.com/us/app/chessmonitor/id6755627535: Stockfish 18 named
E4 :2Marketing claims that can be checked (no overselling)
https://www.chessmonitor.com/: factual wording ("Made in Germany")
FContent and method
0.0F1 :0Courses organized by rating level
no course on https://www.chessmonitor.com/
F2 :0Course authors named and titled
no author on https://www.chessmonitor.com/
F3 :0Content formats (text, video, interactive)
no content on https://www.chessmonitor.com/
F4 :0Published method of progression
no method on https://www.chessmonitor.com/
F5 :0How often the content is updated
no dated teaching content on https://www.chessmonitor.com/
GPlaying and practice
0.0G1 :0Playing humans online (pool, anti-cheating)
no play on https://www.chessmonitor.com/
G2 :0Realistic artificial opponents
no opponent on https://www.chessmonitor.com/
G3 :0Replaying one specific position against the machine
no practice on https://www.chessmonitor.com/
G4 :0Tournaments and organized competition
no tournament on https://www.chessmonitor.com/
HExperience and accessibility
2.7H1 :3Platforms available (web, iOS, Android, desktop)
https://www.chessmonitor.com/: web + https://apps.apple.com/us/app/chessmonitor/id6755627535 + https://play.google.com/store/apps/details?id=com.chessmonitor.app
H2 :0User ratings and reviews (stores, press)
https://apps.apple.com/us/app/chessmonitor/id6755627535: 0 ratings; https://play.google.com/store/apps/details?id=com.chessmonitor.app: 1k+ installs, no rating shown
H3 :0Interface languages available
a single language observed — https://apps.apple.com/us/app/chessmonitor/id6755627535: "Languages: English"
H4 :0Accessibility (keyboard, screen reader)
no information on https://www.chessmonitor.com/
H5 :1Offline use and known incidents
https://www.chessmonitor.com/: online service; no incident reported
IPreparation and study
3.3I1 :2Preparing for a named opponent
https://www.chessmonitor.com/pricing — "View any Chess.com/Lichess player", "Full Opponent View"; App Store: "study their openings"; neither weaknesses nor suggested lines
I2 :0Annotating and sharing games (studies)
https://www.chessmonitor.com/ — no annotation, variation or sharing of analysis
I3 :0Entering a game played at a club (photo, scoresheet)
https://www.chessmonitor.com/pricing — PGN upload only; no board entry, photo or OCR
I4 :2Searching your games (filters, position)
https://www.chessmonitor.com/pricing — filters Date, Time Control, Account, Outcome & Termination, Opponent Strength, Opponent Name
JHuman coaching and community
2.5J1 :0Access to human coaches
no coach on https://www.chessmonitor.com/
J2 :0Size and activity of the community
https://www.chessmonitor.com/pricing: "Community Support" only; no visible forum
J3 :1Tools for trainers, clubs and schools
https://www.chessmonitor.com/pricing: "Up to 5/10 Chess.com accounts" per subscription
J4 :2Engagement mechanics (streaks, virtual currency, reminders)
https://www.chessmonitor.com/: no paid engagement mechanic; scouting and statistics
KPersonal data and interoperability
6.7K1 :1Exporting your data (games, repertoire)
https://www.chessmonitor.com/privacy: export "in machine-readable format" on request
K2 :2Protection of personal data (GDPR, hosting)
https://www.chessmonitor.com/privacy: server in Germany, GDPR, Umami without IP; https://www.chessmonitor.com/pricing: "No ads" reserved for paid tiers
K3 :3Public API and source code
https://github.com/openingtree/openingtree: open-source GPL-3.0 repository
Also, outside the grid
Features found that no criterion measures. They do not count towards the score.
- FIDE rating estimate
- Ultra database of 10M OTB/correspondence games
- Bookmarked players to follow
- OpeningTree: open-source opening tree
Sources consulted
- https://www.chessmonitor.com/
- https://www.chessmonitor.com/about
- https://www.chessmonitor.com/legal
- https://www.chessmonitor.com/pricing
- https://www.chessmonitor.com/privacy
- https://www.chessmonitor.com/blog
- https://www.chessmonitor.com/changelog
- https://www.chessmonitor.com/blog/2026-ultra-database
- https://www.chessmonitor.com/blog/2026-chessmonitor-mobile-app
- https://www.chessmonitor.com/blog/2025-anish-giri-joins-chessmonitor
- https://www.chessmonitor.com/blog/2024-chessmonitor-receives-startup-grant
- https://apps.apple.com/us/app/chessmonitor/id6755627535
- https://play.google.com/store/apps/details?id=com.chessmonitor.app
- https://www.openingtree.com
- https://github.com/openingtree/openingtree
- https://github.com/openingtree/openingtree/releases
- https://github.com/openingtree/openingtree/commits/master
- https://github.com/vjuneja
- https://raw.githubusercontent.com/openingtree/openingtree/master/README.md
Services with a similar profile
The three services whose category profile is closest — a distance over the eleven scores, computed, never chosen.