Take over an existing codebase safely
A safe handover has three parts: you hold all the access, the outgoing team explains what they built, and the new developer starts with a short audit milestone before any big change.
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Why the handover matters
When a developer or agency leaves, knowledge leaves with them. Passwords sit in someone's head, and the way to publish an update is a secret. A planned handover turns that hidden knowledge into notes and access that belong to you. Even a short, friendly one makes the next stage cheaper.
If the other side is not cooperating or has disappeared, see rescue a stuck project. If the product is in good shape and you just need a new developer, continue an existing project is the lighter option.
Access checklist
Make sure the accounts below are owned by you or your company. The developer should be added as a member, not the other way round.
- Code: the repository, with full history and all branches.
- Hosting: servers or cloud account, plus the way updates are published.
- Domain name and DNS settings.
- Database and file storage, with a recent backup you have tested.
- Third party services: payments, email, analytics, maps, AI and push notifications.
- App Store and Google Play developer accounts, and signing certificates for mobile apps.
- Monitoring and error tracking tools.
- Secret keys and settings, shared in a password manager. After the handover, change keys the previous team knew.
Documentation to ask for
- How to run the product on a new computer, step by step.
- A sketch of how the parts connect: apps, servers, database and outside services.
- A list of settings and environment values, without the secret parts.
- How a new version goes live, and how to go back.
- Known problems, shortcuts and unfinished work.
- Licences of code libraries used. This is general information, not legal or tax advice.
Missing documents are normal. Ask for a call with the outgoing developer, recorded if they agree, where they walk through the product. An hour of this saves days later. The guide on who owns the code explains what to settle in writing.
The first audit milestone
Start the new relationship with an audit and no big changes. Each milestone is funded before work starts and runs 1, 2, 3, 4, 6 or 8 weeks. Milestones are from 50 to 2,000 each in your project currency. The new developer should return with:
- Confirmation that the product runs from your accounts.
- A summary of the structure in plain language.
- Risks ranked by impact: security, data, outdated parts and missing tests.
- A list of quick wins and a proposal for the next milestones.
| Topic | What you get | Example timing |
|---|---|---|
| Phase 1: Access and handover call | All accounts under your control, a walkthrough with the outgoing team | For example, 1 week |
| Phase 2: Audit milestone | Running copy, risk report and a plan for the next steps | One milestone, for example 1 to 2 weeks |
| Phase 3: Stabilise | Urgent risks fixed, keys changed, backups and deployment documented | One to two milestones, for example 2 to 4 weeks |
| Phase 4: Regular work | Features and fixes planned from the audit | Milestones as agreed |
Phase 1: Access and handover call
- What you get
- All accounts under your control, a walkthrough with the outgoing team
- Example timing
- For example, 1 week
Phase 2: Audit milestone
- What you get
- Running copy, risk report and a plan for the next steps
- Example timing
- One milestone, for example 1 to 2 weeks
Phase 3: Stabilise
- What you get
- Urgent risks fixed, keys changed, backups and deployment documented
- Example timing
- One to two milestones, for example 2 to 4 weeks
Phase 4: Regular work
- What you get
- Features and fixes planned from the audit
- Example timing
- Milestones as agreed
Example only: the weeks are for illustration. Developers set the length of each milestone in their proposal, and each real milestone runs 1, 2, 3, 4, 6 or 8 weeks.
Questions to ask developers
- What will you check in the first days, and what will I get in writing?
- How do you protect live users while you learn the code?
- Which technologies here are new to you?
- When would you advise against keeping the code as it is?
- How do you keep a handover note up to date as you work?
For more on choosing, read how to hire a developer safely.
Frequently asked questions
What if the outgoing agency does not cooperate?
Start with your contract, which often covers handover duties. Then secure whatever you already have access to. A new developer can still audit the code once they have a copy. This is general information, not legal or tax advice.
Link to this answerHow long should an audit take?
For most small and mid sized products, one milestone. Very large systems may need more time. Agree on what the audit covers and what you receive.
Link to this answerWhy change passwords and keys after a handover?
People who worked on the product know them. Changing them after the handover closes that door. It is a normal routine and not a sign of distrust.
Link to this answerWhat if the code has no tests?
That is common. A developer can add automated tests around the most important flows first, before any larger change.
Link to this answerDo I own the code the agency wrote?
That depends on your contract with them. For new work in milestones: Unless both sides agree otherwise in writing on the platform, the rights to the result of a milestone pass to the client once that milestone is paid in full.
Link to this answerRelated pages
- Hire a Developer to Continue Your ProjectSomeone started your product and now you need it finished or moved forward. Learn how to hand over a project and plan the next milestones.
- Rescue a Stuck App or Software ProjectYour developer disappeared or nobody can change the app anymore. See the first steps, a milestone plan and what to ask a rescue developer.
- Get Expert Advice or a Code ReviewA second opinion on your plan or code before you go further. Learn what a review covers, what to share and how to use the report.
- Who Owns the Code When You Hire a Developer?Learn who owns the code, design and data when a freelancer builds your software, what usually stays with the developer, and how to agree on it in writing.
- How to Hire a Developer SafelyHire a developer with confidence: pay per milestone, fund before work starts, keep payments on one platform, and get access to your code as you go.
- Freelancer vs Agency vs MarketplaceA neutral comparison of hiring a freelancer, an agency or a marketplace for your app, SaaS, website or game: cost, speed, risk and control.