Freelance Developer English Vocabulary: Proposals, Invoices, and Contracts
The complete freelance developer vocabulary guide: SOW, retainer, kill fee, NDA, change order, invoice terms, scope creep, and 50 more terms for independent developers.
Freelance developers write proposals, negotiate rates, draft contracts, and manage client relationships — all in English. Unlike most tech vocabulary, this one is business and legal — different from the vocabulary you use writing code. This guide covers the 50+ terms you need to operate confidently as an independent developer or contractor.
Project Documents
Proposal
A proposal is the document you send a client before the project starts. It describes your understanding of their problem, your proposed solution, timeline, and price.
A solid proposal includes:
- Project overview (problem + solution)
- Scope of work (what you will deliver)
- What is out of scope
- Timeline with milestones
- Pricing
- Payment terms
- Next steps
SOW (Statement of Work)
A Statement of Work is a formal document that defines the work to be performed, deliverables, timeline, acceptance criteria, and price. More formal than a proposal — often attached to or part of the contract.
“Before starting, both parties sign the SOW — it protects us both by defining exactly what I’m delivering.”
NDA (Non-Disclosure Agreement)
An NDA is a legal agreement preventing parties from sharing confidential information. Common before discussing a project. Can be one-way (only you can’t share) or mutual.
“I’m happy to sign your NDA before the discovery call.”
MSA (Master Service Agreement)
An MSA is a framework contract that governs the ongoing relationship between a freelancer and a client — used with multiple SOWs over time. Defines payment terms, IP ownership, dispute resolution, and liability limits.
Contract
A contract is a legally binding agreement. For freelancers, it defines deliverables, timeline, payment, IP ownership, confidentiality, and termination conditions.
Pricing & Payments
Hourly Rate vs. Fixed Price
- Hourly rate — you bill for time worked. Good for unclear scope; risky for clients.
- Fixed price (flat fee) — you charge a single price for the whole project. Good when scope is well-defined.
Retainer
A retainer is a regular payment (monthly) for ongoing availability and work — the client pays whether or not they use all the hours. Provides income predictability for freelancers.
“I have two clients on a 20-hour monthly retainer — it covers my base expenses.”
Milestone Payment
A milestone payment ties payment to specific deliverables. Example: 30% upfront, 30% at mid-point delivery, 40% on final delivery. Reduces risk for both parties.
Upfront Deposit
An upfront deposit (or advance) is a percentage paid before work begins — protects you from abandonment. Typically 25–50% for fixed-price projects.
Net-30 / Net-15 / Net-60
Net-30 means the client has 30 days from invoice date to pay. Net-15 is 15 days. Net-60 is 60 days. Standard for B2B invoicing.
“My standard payment terms are net-15. I charge a 1.5% late fee per month after that.”
Late Payment Fee
A late payment fee (or finance charge) is charged when a client pays after the due date. Must be specified in the contract to be enforceable.
Invoice
An invoice is a formal request for payment. It lists: invoice number, date, due date, itemised services, total amount, payment method, and tax details.
Overage
An overage is the additional fee charged when work exceeds the original project scope — e.g., extra hours worked beyond the fixed-price estimate due to client-requested changes.
Scope & Deliverables
Deliverable
A deliverable is a tangible output of the project — a working feature, codebase, documentation, design, or report — that can be handed over to the client.
Scope
The scope defines the boundaries of the project — what is included and what is not. Clearly defining scope in the contract prevents disputes.
Scope Creep
Scope creep is the gradual expansion of project work without corresponding adjustments to price or timeline. Often caused by informal client requests (“Could you also add…?”).
“Adding the mobile app to the original website project is scope creep — it requires a new SOW and additional fee.”
Change Order
A change order (or change request) is a formal document amending the original SOW to add, remove, or modify deliverables — with updated cost and timeline implications.
“Happy to add the analytics dashboard — I’ll send a change order for the additional scope.”
MVP (Minimum Viable Product)
The MVP is the minimal version of the deliverable that meets the core requirements. Useful for scoping fixed-price projects — agree on MVP first, then iterate.
Acceptance Criteria
Acceptance criteria define the conditions a deliverable must meet for the client to formally accept it. Prevents subjective disputes about whether the work is “done”.
Revision
A revision is a modification to a delivered output. Define the number of free revisions in the contract — e.g., “two rounds of revisions included; additional revisions billed at hourly rate.”
Legal & Contracts
IP (Intellectual Property) Ownership
IP ownership clauses in contracts define who owns the code you write. Options:
- Work for hire — client owns all IP upon final payment
- License — you retain ownership but grant the client a license to use the work
- Dual copyright — common in open-source contexts
“My standard contract transfers all project IP to the client upon receipt of final payment.”
Kill Fee
A kill fee is compensation paid to the freelancer if the client cancels the project after work has begun. Typically 25–50% of the remaining contract value.
“My contract includes a kill fee — if the project is cancelled, the client pays 50% of the remaining balance.”
Termination Clause
The termination clause specifies how and when either party can end the contract — notice period, circumstances, and obligations upon termination.
Indemnification
Indemnification is contractual protection — the client agrees to defend you against claims arising from their content, data, or product (and vice versa).
Limitation of Liability
A limitation of liability clause caps your financial exposure — typically limited to fees paid under the contract. Protects freelancers from catastrophic client claims.
Non-Compete
A non-compete clause restricts you from working for the client’s competitors for a defined period. Be cautious — overly broad non-competes can harm your business.
Client Communication
Discovery Call
A discovery call is an initial meeting to understand the client’s problem, budget, and timeline — before you write a proposal. Essential for scoping accurately.
Onboarding
Onboarding is the process of setting up a new client: contracts signed, access granted, communication channels established, first milestone defined.
Check-In / Status Update
A check-in (or status update) is a regular brief communication — email or call — to keep the client informed of progress. Proactive communication prevents client anxiety.
Sign-Off
Sign-off is formal acceptance of a deliverable. Get written sign-off (email or contract signature) at each milestone — protects you from later claims of incomplete work.
Escalation
An escalation is raising an issue to a higher level when it cannot be resolved at the current level — e.g., if a client contact is unresponsive, escalating to their manager.
Business Operations
Sole Trader / Sole Proprietor
A sole trader (UK) / sole proprietor (US) operates as an individual — simplest structure, personal liability for debts.
LLC (Limited Liability Company)
An LLC separates your personal assets from business liabilities. In the US, the default structure for freelancers who want liability protection.
Limited Company (Ltd)
In the UK, a Limited Company provides the same liability protection as an LLC. Common for freelancers in the UK.
IR35 (UK)
IR35 is UK tax legislation determining whether a contractor is effectively an employee — in which case the client (or umbrella company) must withhold tax. Critical for UK contractors.
B2B vs. B2C
- B2B (Business-to-Business) — you work for companies. Usually higher rates than B2C.
- B2C (Business-to-Consumer) — you work for individuals. More common on platforms like Fiverr.
Umbrella Company
An umbrella company employs contractors — handling payroll, taxes, and employer obligations — allowing you to work on short contracts without setting up your own company.
Useful Phrases
In proposals:
- “Based on our discovery call, I propose a fixed-price engagement for the following scope…”
- “This quote includes two rounds of revisions. Additional revisions are billed at my hourly rate.”
- “This project is estimated at X. To begin, I require a 40% deposit.”
When scope creep occurs:
- “I’m happy to add the feature you mentioned. This is outside the original scope — I’ll send a change order for the additional work.”
- “To keep us on track for the deadline, I’d suggest we add this to a Phase 2 SOW.”
On late payment:
- “This invoice was due on [date]. As per our agreement, a late payment fee of 1.5% per month applies from that date.”
On project completion:
- “All deliverables outlined in the SOW have been completed and are ready for your review and sign-off.”
Practice
Test your freelance vocabulary with the Freelance & Contractor exercise set — 5 exercises covering proposals, contracts, and client communication.
Explore the Freelance Developer learning path for proposal writing, negotiation exercises, and email templates.