What if the current vendor won’t cooperate?

The transition takes longer and relies more on reading the code and infrastructure. Your contract’s handover terms matter; involve your lawyer if needed. Securing assets first protects you either way.

Can we keep the old vendor for a while in parallel?

Often a good idea: a paid overlap period for knowledge transfer and support reduces risk significantly.

Guide · Vendor transition

Switching vendors without a rewrite.

Changing development vendors feels risky because it often is — mostly because of what the old vendor knows and you don’t. Done in the right order, a transition takes weeks, not months, and the new team doesn’t need to start over.

By Nythrex EngineeringUpdated 24 September 2026 2 min read

Secure assets

Accounts · repos · credentials

Notice & plan

Contract terms · schedule

Knowledge transfer

Walkthroughs · docs · Q&A

Shadow & reverse-shadow

New team leads, old supports

Full handover

Access revoked · keys rotated

047 weeks

An orderly transition. Its length depends mostly on documentation quality and cooperation.

Before you tell anyone

Make sure your company controls

0/6

Not sure how exposed you are? Take the vendor lock-in test, and check the contract’s IP and exit clauses with Who really owns your code?.

The handover checklist

0/10

Running the transition

1
Clean build
The new team builds and deploys from scratch into a new environment. Every failure reveals missing knowledge to ask about while the old team is still available.
2
Walkthroughs
Recorded sessions per area: architecture, data, integrations, deployment, operations.
3
Shadowing
The new team watches the old team handle real tasks, then swaps roles (reverse shadowing).
4
Cut-over
The new team takes full responsibility. Old access is revoked and all credentials rotated.

Frequently asked questions

ServiceProject rescueVendor gone, deadline slipping, code nobody understands? We take over troubled software and AI projects: fast audit, stabilisation, a plan you can trust.Free toolVendor lock-in testTwelve questions about code, cloud, access, contracts and docs reveal how locked in you are to your development vendor — with a prioritised fix list.GuideWho really owns your code?Paying for software doesn’t make it yours. The clauses that decide code ownership: IP assignment, background IP, open source, AI assets, exit terms.Guide13 red flags your vendor is hiding problemsVague reports, shifting dates, no access to code: 13 signs your outsourced project is in trouble — and what to ask or do about each this week.Example projectRescuing a stalled marketplaceIllustrative rescue: a marketplace nine months late, code in the vendor’s account, no tests. How we’d secure assets, audit, decide and ship.

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