06 — Prepositions (in, on, at, to, for, with)

What this fixes for you: prepositions are the small words you keep guessing — “depend on” or “depend to”? This doc gives you a cheat table so you stop guessing and just know.

The rule in 30 seconds

• Time/place follow a zoom rule: in = big/inside (in June, in the repo), on = surface/day (on Monday, on the branch), at = exact point (at 9am, at line 42).
• Most dev prepositions are fixed pairings (collocations) — depend on, based on, responsible for. You memorize these; you do not work them out from logic.
• Direction uses to: push to, deploy to, merge to. Being inside something uses in/on: in the repo, on the branch.
• When in doubt, check the cheat table at the bottom. Real English speakers also just memorized these.

Why this trips you up

In your native language one preposition often covers several English ones, so you translate word-for-word and get “depend to” or “responsible of.” You also mix the zoom levels — writing “on the repo” when it’s “in the repo.” The fix is not grammar logic; it’s pairing the verb and its preposition together as one chunk and reusing it.

See it / fix it

❌ What you tend to write	✅ Correct	Why
this fix depend to the cache layer	This fix depends on the cache layer.	The verb is depend on, always. Also capitalize the first word and add the full stop.
i merged the branch to main	I merged the branch into main. (or to main)	You merge code into a target. Capitalize I.
pushed my changes in the remote	Pushed my changes to the remote.	Pushing is direction → to, not in.
the price is based of the tier	The price is based on the tier.	Fixed pair based on. Never based of / based off in formal writing.
who is responsible of this module	Who is responsible for this module?	responsible for. And it’s a question → add ?.
she is good in debugging	She is good at debugging.	good at a skill. in is wrong here.
i am interested on the new ticket	I’m interested in the new ticket.	interested in, always. Capitalize I.
the server listen in port 4000	The server listens on port 4000.	A service listens on a port. Add the -s (it listens).
we will deploy in production tonight	We’ll deploy to production tonight.	Deploy is direction → to an environment.
can u comment in my PR	Can you comment on my PR?	You comment on something. Spell out you.
working in a ticket about grammer	Working on a ticket about grammar.	You work on a task. Fix the spelling: grammar.
the file is on the repo on branch dev	The file is in the repo on branch dev.	You’re in a repo (container) but on a branch.

Patterns to remember

Time & place — the zoom rule (big → small):

Word	Time	Place
in	in 2026, in June, in an hour	in the repo, in the file, in production
on	on Monday, on June 16, on the weekend	on the branch, on line 42, on a server
at	at 9am, at noon, at deploy time	at the endpoint, at the office

Dev collocation cheat table (memorize the pairing, not the logic):

Phrase	Preposition	Example
depend ___	on	The job depends on Redis.
based ___	on	Pricing is based on quantity.
responsible ___	for	I’m responsible for the queue worker.
good ___ (a skill)	at	He’s good at writing tests.
interested ___	in	I’m interested in the caching task.
listen ___ (a port)	on	The service listens on port 8000.
deploy ___ (an env)	to	We deploy to staging first.
push ___ (a remote)	to	Push to origin.
merge ___ (a target)	into / to	Merge into main.
work ___ (a task)	on	I’m working on the bug.
comment ___ (a thing)	on	Please comment on the PR.
reply ___	to	Reply to the review thread.
connect ___	to	Connect to the database.
migrate ___	to	Migrate to PostgreSQL.
consist ___	of	The pipeline consists of three stages.

Quick mnemonic: Moving somewhere → to (push to, deploy to, reply to). Sitting inside → in (in the repo, in production). On a surface or a list → on (on the branch, on a port, on the PR).

In your daily writing

• Commits: “Fix crash that depends on a null tenant” — not “depend to.”
• PR titles: “Deploy worker to staging” / “Merge feature into main.”
• Slack standups: “Today I’m working on the cache ticket and will comment on Pravin’s PR.” — not “working in” / “comment in.”
• Code comments: // Service listens on port 4000 — not “listens in port.”
• Bug reports: “The error happens in production at the checkout endpoint on the release branch.” Notice each zoom level gets its own word.

Drills

Fix the preposition (and any spelling/capital/punctuation slips you notice).

1. the build depend to a env variable that is not set
2. i am interested on picking up the payment ticket
3. we deploy in production every friday
4. can u comment in my pull request when u get time
5. the price calculation is based of the product size
6. who is responsible of the queue worker
7. our api listen in port 8000 by default
8. she is really good in writing clean tests
9. Choose A or B: I’ll push my changes (A) to / (B) in the remote tonight.
10. Choose A or B: The config file is (A) on / (B) in the repo, (A) on / (B) in the dev branch.
11. Fill the blank: This migration consists ___ two reversible steps.
12. Fix the run-on: i fixed so much bug today and i will merge to main and then i deploy in staging

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Answer key

1. The build depends on an env variable that is not set. — depend on; add -s, capitalize, use an env, add full stop.
2. I’m interested in picking up the payment ticket. — interested in; capitalize I.
3. We deploy to production every Friday. — Direction → to; capitalize the day Friday.
4. Can you comment on my pull request when you get time? — comment on; spell out you; it’s a question → ?.
5. The price calculation is based on the product size. — Fixed pair based on, not based of.
6. Who is responsible for the queue worker? — responsible for; add the question mark.
7. Our API listens on port 8000 by default. — A service listens on a port; add -s.
8. She is really good at writing clean tests. — good at a skill, not good in.
9. A — to. — Pushing is direction, so push to the remote.
10. B (in the repo), A (on the dev branch). — You’re inside the repo but on a branch.
11. of — consist of. (The migration consists of two reversible steps.)
12. I fixed so many bugs today. I’ll merge into main and then deploy to staging. — so many bugs (countable, plural); split the run-on into sentences; merge into; deploy to; capitalize I.

Part of the Developer English course — see 00-index.md.