Blindspot

Introduction

Blindspot is a web-based English writing checker built on a specific pedagogical claim: learners repeat the same errors because nobody ever explained the rule behind the correction. Instead of silently rewriting a sentence, the platform flags the mistake, presents the corrected form, and attaches a plain-language explanation of the grammar that governs it. The service targets intermediate and upper-intermediate English learners — with Russian speakers clearly in view, given the bilingual interface — and bundles a text checker, a vocabulary notebook, and an adaptive grammar trainer into a single account.

Key Features

Writing check with rule-level explanations. The core loop is deliberately explanatory rather than cosmetic. A sample sentence — "Yesterday I didn't saw my friend at the university" — returns a two-part response: a correction that strikes "didn't saw" and substitutes "didn't see", followed by a short note stating that "didn't" already marks past tense, so the following verb stays in its base form. That structure sidesteps the common failure mode of grammar tools that produce cleaner text without teaching anything transferable.

Mistake clustering into shared grammar topics. Individual corrections are not treated as isolated events. The grammar preview shows three separate learner sentences — "didn't saw my friend", "didn't went to the meeting", "didn't understood the instructions" — collapsed into one named topic: Past Simple negative sentences. Aggregating errors this way turns scattered red marks into a small number of identifiable weak spots.

Adaptive practice generation. Once a topic exists, the platform builds exercises around it. The demo question "She didn't ___ to the meeting" offers went, go, and going, testing precisely the rule the learner broke. Practice therefore derives from the learner's own output rather than a generic curriculum.

Vocabulary capture with linguistic depth. The vocabulary module is more than a word list. Entries such as endeavour arrive with a summary gloss, separate noun and verb definitions, an authentic usage example, collocations ("make every endeavour", "creative endeavour", "endeavour to understand"), and synonyms grouped by part of speech. Flashcards follow from the same record, so saving a word is the only step needed to schedule it for review.

Chrome extension for in-context saving. A Chrome extension lets a learner select any word during a normal browsing session and click a plus control to push it into the personal dictionary, complete with a translated gloss. A second tab in the same extension runs writing checks inline, returning corrected text alongside grammar notes such as "base form after 'didn't'". Reading, saving, and checking stay inside one window.

Placement and localization. A free English level test provides an entry point for users who do not know where to begin, and the interface ships in English and Russian with reciprocal hreflang declarations for both locales.

How It Works

The workflow is short by design. A visitor lands on a single-field form, pastes or types between 30 and 300 characters of English, and submits. If no session exists, a Google sign-in window opens while the draft is retained in the current browser tab, so nothing is lost during authentication. The learner then selects a native language if one has not already been set, and the check runs.

Once inside an account, the same checker accepts texts up to 5,000 characters — enough for an email, a work note, or several paragraphs of free writing. Results arrive as a structured review: the corrected sentence, the reasoning behind each change, and an optional vocabulary suggestion extracted from the text. Saving a suggested word is a manual decision, which keeps the personal dictionary focused rather than auto-inflated.

Submitted texts are analysed through OpenAI, and both the source text and the resulting feedback are stored in the account, creating a running record that the grammar module can mine for patterns. Over time that record becomes the curriculum: repeated structures surface as topics, and topics generate question sets. The whole loop — write, check, understand, drill — is available from a browser without installing desktop software.

Use Cases

Intermediate learners with fossilized errors. The profile the product fits best is someone whose English is functional but repeatedly slips on structures like Past Simple negation, articles, or verb patterns. Standard checkers fix the sentence and move on; Blindspot names the rule, which is the missing piece for learners who have seen the rule before but never connected it to their own writing.

Russian-speaking professionals. The bilingual English/Russian interface, Russian-language glosses in the extension popup, and translated source words inside feedback panels (for example, готовился mapped to "was preparing / was studying") make the platform unusually convenient for that audience compared with English-only competitors.

Workplace and academic writing. Because the in-account checker handles up to 5,000 characters, the tool suits emails, reports, cover letters, and discussion posts — real texts with consequences, where an explanation of why a construction was wrong is worth more than a silent rewrite.

Self-directed vocabulary building. Learners reading articles or documentation in Chrome can capture unfamiliar words as they encounter them, then review generated flashcards later, turning passive reading into scheduled retention work.

Tutors and study routines. A tutor can use the extracted grammar topics as an objective summary of a student's recurring weaknesses, while the free level test gives new learners a starting point before any paid commitment.

Pricing & Value

The entry point is free and explicitly card-free: an account unlocks text checks and personalized practice at no cost, and payment is positioned as a later, optional upgrade for heavier usage. The marketing pages do not publish tier names or per-check limits, so the exact threshold where free usage ends is not documented publicly.

Value assessment therefore rests on the format rather than the price sheet. Free tiers in this category typically deliver a corrected string and a suggestion count; Blindspot's free layer includes the explanatory note, the grammar topic clustering, the practice question, and the vocabulary record. For a learner who values understanding a rule once over fixing a sentence repeatedly, the free tier alone carries unusual utility. The paid tier is likely to matter most to high-volume users — people checking several texts per day or drilling continuously.

Final Verdict

Blindspot occupies a defensible niche between two crowded categories: grammar checkers that correct quietly and language apps that teach from generic syllabi. Its differentiator is the feedback contract — every correction comes with a reason, and every cluster of reasons becomes a drill. Combined with a vocabulary module that captures collocations and synonyms rather than bare translations, plus a browser extension that removes friction from both saving and checking, the product delivers a coherent study loop from a single account.

The caveats are practical rather than conceptual. The public demo is capped at 300 characters, so the free trial experience is a snapshot rather than a full test. Pricing structure is not published, which makes cost forecasting difficult for teams or heavy users. Distribution is also narrow: two locales, no dedicated mobile apps, and a Chrome-only extension. Learners who work primarily on mobile, or who need languages beyond English, will find the surface area limited.

For its intended user — an intermediate learner, especially a Russian speaker, writing English in a desktop browser and wanting to stop repeating the same mistakes — Blindspot is a well-scoped tool with a clear method. Those users should run a text through the checker, inspect the explanation quality on a known weak point, and judge the drilling from there.