The developer who’s been building your site knows things nobody wrote down. Which of the twelve comments from three weeks ago actually got fixed. Why the pricing page still says “coming soon.” What “make it pop more” turned into after the second round of back-and-forth. None of that is in a spec. Most of it isn’t even in Slack anymore — it’s in their head.

Then they leave. A contract ends, an agency gets reassigned, a freelancer takes another client. And the founder is left trying to reconstruct six weeks of review history from memory, half-read Slack threads, and a folder of screenshots nobody labeled.

This isn’t a rare event. It’s a predictable one, and it has a predictable fix: stop storing review history in a person, and start storing it in a shared, status-tracked record that survives whoever’s currently building the site.

Why does switching developers mid-project lose so much feedback?

It loses feedback because most teams store review history in tools that were never built to outlive a single relationship — a Slack workspace, a person’s inbox, or a departing developer’s mental model of what’s done.

Slack is the biggest silent offender. A huge share of small teams run on Slack’s free tier, and Slack’s own help center is explicit about what that tier retains: on the free plan, workspaces are “limited to the most recent 90 days of message and file history,” and anything older than a year is deleted outright. If your website review has been running for four months, the first month of feedback — including the decisions everyone thinks are “already settled” — may already be invisible to search, whether or not the developer who made those calls is still around to remember them.

And developer turnover mid-project isn’t an edge case worth ignoring. Even at the high end of the industry, agency relationships don’t last indefinitely. The 2025 ANA/4As Client-Agency Relationship Tenure study found the average client-agency relationship now runs about seven years — but tenures compress sharply under specific conditions: clients with mandatory periodic reviews average just 3.8 years with an agency, versus 8.1 years for those without them. A single website build or redesign is a fraction of that timeline, but the same forces apply at smaller scale — budget reviews, staffing changes, a freelancer’s other clients — and any one of them can end a developer relationship mid-project, not at a clean milestone.

Put those together and you get the actual failure mode: review history degrades on a fixed clock (Slack’s 90 days) while developer relationships end on an unpredictable one. The gap between those two timelines is where feedback gets lost.

What feedback history actually needs to survive the handoff?

Not everything — three things: what’s still open, what’s already been decided, and what the site looked like when the review started. Trying to hand off the entire six-week conversation is how handoffs turn into archaeology instead of onboarding.

Dumping raw context on a new developer doesn’t solve this, and there’s decent evidence it makes things worse. Analysis from the Stack Overflow engineering blog on developer documentation found that when documentation is inadequate, developers spend “more than 30 minutes a day searching for solutions to technical problems,” and that outdated documentation “can mislead developers, leading to errors” rather than simply failing to help. A pile of old Slack threads and a “here’s roughly where we are” call from the outgoing developer isn’t neutral — it’s a source of active misdirection if any of it is stale, and after weeks of review, some of it always is.

What actually needs to make the trip:

Every open item, with enough context that the new developer doesn’t have to guess what “fix the spacing here” meant three weeks ago.
Every resolved item, marked resolved — so nobody relitigates a decision that already got made.
The visual baseline the review started from, so the new developer can see what changed and what didn’t.

That’s a status list, not a novel. If you can’t compress the handoff to those three categories, the review process itself was the problem, not the personnel change.

How do you hand off review history so a new developer doesn’t start blind?

You give them access to the record, not a summary of it. The single highest-leverage move in a developer handoff is inviting the incoming developer into the same place the outgoing one was already working — not writing a document that’s accurate on the day you write it and wrong a week later.

This is the same logic GitLab uses to run an entire company remote-first: documentation isn’t a courtesy extended to people who couldn’t make the meeting, it’s the actual source of truth. GitLab’s own handbook describes a “handbook-first” approach where written, centralized records are the default and verbal explanation is the exception — specifically so that institutional knowledge doesn’t live only in the heads of people who happen to be in the room, or on the team, at a given moment. A website review has the same structure at a smaller scale: whatever isn’t written down and centralized only exists for as long as the person who remembers it sticks around.

In Simpl_Markup, that’s what a workspace already is — a founder pastes the site URL in Slack, Simpl_Markup generates the desktop, tablet, and mobile baseline screenshots, and every comment anyone pins after that carries a status: open, fixed, or approved. That status list doesn’t belong to the developer who’s leaving; it belongs to the workspace. Adding the incoming developer is an admin sending an invite, not a re-explanation. Because pricing is per workspace rather than per seat, swapping developers doesn’t touch the bill either — the workspace has room for the new person the moment they accept.

Compare that to the default pattern: a folder of exported screenshots, a Google Doc titled “Handoff Notes,” and a scroll through Slack hoping the important messages haven’t already aged past the 90-day search window. That approach — the screenshot-and-Slack-DM workflow most teams default to — was already losing context during ordinary review. A personnel change just makes the loss visible all at once instead of gradually.

What should the new developer’s first review pass actually look like?

It should be a structured audit of the existing record, not a live walkthrough with the person leaving. Have the new developer go through three things before writing a single line of code:

Every open item, in priority order. What’s still unresolved, and what did the founder actually ask for — not what the new developer assumes they meant.
A spot-check of the approved items. Confirm what’s marked “fixed” actually matches production. Status only means something if it’s trustworthy, and the fastest way to lose a founder’s confidence in a new developer is relitigating something that was already signed off.
The original baseline against the current state. What’s changed since the review started, and does that match what the open and resolved items say should have changed?

This is deliberately not a call. A live walkthrough compresses six weeks of context into forty-five minutes of one person talking while the other tries to keep up — and whatever doesn’t get mentioned on that call is gone. A written, pinned record of feedback doesn’t have that failure mode: the new developer can go through it at their own pace, and nothing depends on the outgoing developer remembering to mention it before their last day.

How do you make sure this doesn’t happen again next time you switch developers?

You centralize review history before you need to hand it off, not after. The teams who navigate a developer switch cleanly aren’t the ones with a great offboarding process — they’re the ones whose review history was already living somewhere durable, so there was nothing special to hand off in the first place.

That means treating the review workspace as permanent infrastructure for the project, independent of who’s currently building it. The URL gets pasted once, the baseline screenshots get generated once, and every comment from that point forward — regardless of which developer, agency, or freelancer is on the other end of it — carries the same status and lives in the same place. When the next transition happens, and per the tenure data above it eventually will, onboarding the replacement is an invite, not a reconstruction project.

The founders who get burned by a developer handoff aren’t the ones who picked the wrong developer. They’re the ones who let review history live in a relationship instead of a record. Fix that once, at the start of a project, and every future switch gets cheaper.