I have seen saw him yesterday.
'yesterday' is finished time — use past simple.
Past simple vs. present perfect
review_due
patched
The grammar repair shop · Coming soon to the App Store
The mistakes you keep repeating? Patched.
GrammarPatch finds your recurring tense and preposition bugs and repairs the pattern behind them — built for intermediate English learners (A2–C1).
Coming soon to theApp Store
Free Patch Scan at launch · iOS 16+ · Your text stays in the EU
Tenses + prepositions, done properly
~5 min per patch
EU-only data
No ad trackers
Patch Scan
scan complete
I am responsible of for sales.
responsible takes for — it's a fixed pairing.
Adjective + preposition
review_due
patched
I live have lived here since 2020.
since + a start point needs present perfect.
for / since + present perfect
review_due
patched
You know this moment
You sent it. Then you saw the mistake.
Not because you don't know the rule — you do. It's the same handful of bugs, slipping through in the moments your English has to be right.
The client email
"I have seen the offer yesterday."
Sent. The client noticed before you did.
The interview
"I am responsible of a team of five."
Said out loud. The interviewer heard it too.
The exam
"I live in Hamburg since 2020."
Marked down again — the same deduction as last time.
You knew every one of these rules. Knowing the rule was never the problem.
Read the repair method: how to stop repeating the same English mistakes →
Patch Map3 Grammar Bugs
High
responsible of for
review_due
Medium
since live have lived
improving
Low
have seen saw yesterday
patched
3bugs found
22% → 58%patched
Tuenext review
The diagnosis
One short scan. Your recurring bugs, mapped.
A Patch Scan reads your writing the way a mechanic reads an engine — and surfaces the specific tense and preposition patterns you repeat, each with its severity, its rule, and how close it is to patched.
How it works
Diagnose the bug, then repair it until it's gone.
Four steps that map to the app itself — a repair shop, not a classroom. A few minutes at a time.
1Diagnose
Patch Scan
A short scan surfaces the tense and preposition bugs you repeat most.
3
Grammar Bugs found
2See the pattern
Patch Map
Every Grammar Bug laid out with its rule, its clue, and how close it is to patched.
High
responsible of for
Medium
since live have lived
3Repair
Quick Patch
Five-minute practice built around your specific mistakes — never a generic course. The rule is always revealed.
I ____ him yesterday.
4Make it stick
Patch Review
Spaced reviews bring each bug back until it's genuinely patched.
new
active
review_due
improving
patched
Beyond the scan
Repair with your own sentences.
The loop keeps working on the English you actually write — classified, repaired, and reviewed until each bug is genuinely gone.
Real Use
Paste a sentence you actually wrote — an email, a message — and get it patched against your own bug list.
I will discuss about discuss it on in the meeting.
Error DNA
Every bug is classified against a taxonomy of the mistakes intermediate learners actually make — so practice targets the real pattern.
tense: perfect-vs-past
tense: since / for
prep: fixed pairings
prep: time & place
Patch Review
Spaced repetition brings each bug back on schedule — a little at a time — until it reaches patched.
✓
✓
Tue
+3
+7
+14
Why not just…?
The honest comparison.
Other tools are good at what they do. None of them repairs the recurring pattern behind your own mistakes.
| Approach | Finds your recurring pattern | Practice that sticks | Built for A2–C1 |
|---|---|---|---|
| Grammar checkersFix the text in front of you — not the habit. | — | — | — |
| Language courses & appsTeach everything — not your bugs. | — | ✓ | ✓ |
| ChatGPTAnswers when you ask — no diagnosis, no spaced review. | — | — | — |
| GrammarPatchFinds your recurring bugs, repairs the pattern, reviews until patched. | ✓ | ✓ | ✓ |
A general chatbot can explain any rule you already know to ask about. GrammarPatch tells you which ones to ask about — from your own writing — and makes sure they stick.
Read the full, honest comparison — including when not to choose GrammarPatch →
Private by design
Your English is yours.
Learner text is personal data, and we treat it that way — stored in the EU, never sold, never used to train models, and deletable whenever you want.
EU-only storage
Your text lives in AWS Frankfurt (eu-central-1) — nowhere else.
Never trains AI models
Our processor is contractually barred from training on your text (per our DPA).
Deletable in Settings
Remove your writing history — or your whole account — in one action.
No cookies, no ad trackers
This site sets no cookies and keeps only anonymous, aggregate stats.
Who it's for
Built for the moments your English has to be right.
Professionals
Emails & meetings
When a slip in a client note undercuts otherwise strong work.
"Please revert reply to me until by Friday."
Job candidates
Interviews in English
When you want the interviewer listening to your answer, not your grammar.
"I am responsible of for a team of five."
Exam takers
IELTS · TOEFL · Cambridge
When the same recurring error keeps costing you writing-band points.
"I live have lived here since 2020."
Pricing
Start free. Go unlimited when it's paying off.
Find your first Grammar Bugs at no cost, then go unlimited with a 7-day free trial.
Free
$0
Enough to find your first Grammar Bugs.
- 1 Patch Scan
- 3 Quick Patches
- 2 Real Use submissions
7-day free trial
Pro
Unlimited repair for every bug on your Patch Map.
- Unlimited Patch Scans, Quick Patches & Patch Reviews
- Unlimited Real Use submissions
Billed through the App Store. Cancel anytime in your App Store settings.
Questions
Straight answers.
Is GrammarPatch a grammar checker?
No. A grammar checker corrects the text in front of you and moves on. GrammarPatch finds the tense and preposition mistakes you keep repeating — your Grammar Bugs — explains the rule and the clue behind each one, and repairs the pattern with short practice and spaced review until it is patched.
What English levels is it for?
Intermediate learners, roughly CEFR A2 to C1 — people who already know most of the rules but still repeat the same handful of mistakes in real writing.
What grammar does version 1 cover?
English tenses and prepositions, done properly — not every grammar topic at once. Focusing on the two areas that produce the most recurring mistakes lets us diagnose and repair them well, rather than covering everything shallowly.
Where does my text live?
Your learning text is stored only in the EU — AWS in Frankfurt (eu-central-1) — encrypted, never used to train AI models, never sent to analytics, and deletable anytime in Settings.
How much does it cost and how does the trial work?
The Free tier includes 1 Patch Scan, 3 Quick Patches, and 2 Real Use submissions. Pro is $9.99 per month or $59.99 per year with a 7-day free trial, billed through the App Store — cancel anytime in your App Store settings.
Patch your first Grammar Bug at launch.
Find the mistakes you keep repeating — and finally fix the pattern behind them.
Coming soon to theApp Store