Dev agency case study template
Dev agency case study template
A dev agency case study is a 600 to 1,200 word narrative that walks a future client through a past engagement: client problem, technical constraints, the architecture you chose, the trade-offs you made, the measurable result, and a direct quote from the buyer. The template below is engineering-specific, not marketing-speak: it forces you to name your stack, expose your latency numbers, and admit what you would do differently.
Most agency case studies fail because they read like brochures. The buyer (usually a technical founder or a head of engineering) is scanning for three things: did you understand the constraint, did you pick a defensible architecture, and did the numbers move. Anything else is decoration.
Why most dev agency case studies underperform
Walk through the case study pages on the top 20 agency sites and you find the same four problems:
- No stack named. "We built a scalable web app" with no mention of Postgres, Next.js, Temporal, or the actual database choice.
- No metric that matters. "Increased engagement by 40%" instead of "P95 checkout latency dropped from 2.4s to 380ms."
- No trade-off section. Every decision is presented as optimal. Real engineering has trade-offs; pretending otherwise signals you have not shipped much.
- No client voice. A pull-quote ghostwritten by the agency, attributed to a director nobody can find on LinkedIn.
The fix is structural. A dev agency case study should follow a template that forces honesty, because honesty is the differentiator. Buyers can spot recycled marketing copy in three seconds. They cannot fake-skim a real architecture decision.
The reusable dev agency case study template
Use this seven-section structure for every engagement. Aim for 900 words. Anything shorter looks thin; anything longer loses the buyer.
Section 1: One-line summary (≤30 words)
The headline plus a single sentence. Example: "Rebuilt a fintech onboarding flow on Next.js + Supabase. P95 latency dropped 84%, trial-to-paid conversion rose from 11% to 19%."
This is what shows up on the case-study index page and in your LinkedIn posts. Write it last; it is the hardest sentence in the whole document.
Section 2: Client problem (100 to 150 words)
Name the company, the stage, the team size, and the exact problem. Not "the client struggled with scale." Say "a Series A B2B SaaS with 14 engineers had a 9-second checkout flow that was costing them an estimated $180K in abandoned trials per quarter."
If the client cannot be named (NDA, common), use the pattern "a 40-person Series B logistics company in the EU." Be specific enough that a reader in a similar shape can self-identify.
Section 3: Technical constraints (80 to 120 words)
List them as bullets. This is the part most agencies skip; it is the part technical buyers read first.
- Existing stack you had to integrate with
- Compliance requirements (SOC 2, HIPAA, PCI, GDPR)
- Team handover model (your team only, embedded with theirs, lift-and-shift)
- Performance budgets (latency, bundle size, cold-start tolerance)
- Deadline and budget envelope
Constraints are the case study's credibility check. If you list none, you are pretending the problem was greenfield, and greenfield engagements are rare enough that the buyer will assume you are bluffing.
Section 4: Architecture chosen (200 to 300 words, with diagram)
Name every component. Not "a modern serverless backend"; say "Next.js 15 App Router on Vercel, Postgres on Neon, background jobs on Inngest, auth on Clerk, payments on Stripe Checkout, observability on Axiom."
Include a one-paragraph rationale for the three or four most contested decisions. Example: "We picked Inngest over Temporal because the team had no prior workflow-engine experience and the operational overhead of a self-hosted Temporal cluster was a worse trade than Inngest's per-event pricing at their volume."
A simple ASCII or Mermaid diagram beats a polished marketing illustration here. Buyers want to see the data flow, not the brand colors.
Section 5: Trade-offs (100 to 150 words)
This is the section that separates real case studies from sales sheets. List two or three things you would do differently and why.
Example: "We chose Server Actions for the form submissions because the team wanted a single language for client and server. If the project restarted today on Next.js 16, we would split the heaviest endpoints into route handlers because Server Action error boundaries are still less mature."
Trade-off honesty is the most underpriced trust signal in agency content. Founders who have built anything recognize the voice instantly.
Section 6: Metrics (the table)
A real metrics table, not a bar chart of vanity numbers. The four categories that matter to technical buyers:
| Metric | Before | After | Delta |
|---|---|---|---|
| P95 checkout latency | 2,400 ms | 380 ms | -84% |
| Trial-to-paid conversion | 11.2% | 19.4% | +73% |
| Monthly infra cost | $4,800 | $2,100 | -56% |
| Mean time to deploy | 47 min | 6 min | -87% |
| Production incidents / mo | 6.3 | 1.1 | -83% |
If you do not have before-numbers, say so. "We did not have baseline latency data for the legacy stack; the 380 ms number is the steady-state P95 four weeks post-launch." That sentence builds more trust than a fabricated baseline.
Section 7: Testimonial (50 to 80 words, with attribution)
A real quote from a real person, with their full name, title, and LinkedIn URL. Anything less is treated as fiction.
The best testimonials are specific: "They argued with us about three of our requirements and were right on two of them" beats "great team, would hire again." Coach your client to be specific when you ask for the quote.
A full sample case study using the template
Below is a complete worked example. Use it as a mental model when you write your own.
Headline: Rebuilt a fintech onboarding flow on Next.js + Supabase. P95 latency dropped 84%, trial-to-paid conversion rose from 11% to 19%.
Client problem. Northstar Treasury (a Series A B2B treasury-management SaaS, 14 engineers, ~$3M ARR) had a 9-second checkout flow built on a Rails monolith with a React 16 SPA front-end. Their conversion analytics showed a 71% drop-off between step 2 (bank-link) and step 3 (payment). Internal estimates put the cost of the drop-off at $180K per quarter in lost annual contract value.
Technical constraints.
- Stack lock-in: Rails monolith stays, owns billing logic; we owned the new web front-end and an edge API layer.
- SOC 2 Type II in flight; any new third-party vendor required a security review.
- Plaid was non-negotiable for bank-linking; the existing Plaid integration was on the Rails side.
- Performance budget: P95 sub-500ms for the full onboarding flow.
- Six-week deadline before their Series B kickoff.
Architecture chosen. Next.js 15 (App Router) on Vercel, Postgres on Supabase for new onboarding-session state (not user-of-record data, which stayed in Rails), Server Actions for form submissions, an edge middleware layer to proxy authenticated calls to the Rails monolith, Stripe Elements for the card capture (kept off our servers for PCI scope reduction), and Axiom for log streaming. State machine for the onboarding flow built with XState.
We picked Supabase over a fresh Postgres on RDS because the team needed row-level-security defaults out of the box and the SOC 2 review for Supabase was already complete. We picked XState over a homegrown reducer because the flow had 11 states with 23 transitions and the team had not built a state machine of that complexity before.
Trade-offs.
- We used Server Actions for the bank-link confirmation step. In hindsight a dedicated route handler would have given us cleaner retry semantics; Server Action error boundaries swallowed two production incidents before we added explicit error logging.
- We kept the Rails monolith authoritative for billing. This was correct for the timeline but means a second project is needed to consolidate the auth model.
Metrics.
| Metric | Before | After | Delta |
|---|---|---|---|
| P95 onboarding flow latency | 9,100 ms | 420 ms | -95% |
| Trial-to-paid conversion | 11.2% | 19.4% | +73% |
| Monthly infra cost (onboarding stack) | $2,800 | $1,200 | -57% |
| Engineering time per onboarding tweak | 4-6 hours | 30-45 min | ~85% faster |
Testimonial. "They pushed back on our original spec twice and both times they were right. The Plaid retry logic they shipped is still the cleanest code in our codebase." Maya Olsen, VP Engineering, Northstar Treasury (LinkedIn link).
Good vs bad agency case studies, side by side
A practical comparison. Same project, two write-ups:
| Element | Bad case study | Good case study |
|---|---|---|
| Headline | "Helping Northstar scale" | "Rebuilt fintech onboarding; P95 dropped 84%, conversion up 73%" |
| Stack | "Modern web framework with cloud database" | "Next.js 15 App Router on Vercel, Postgres on Supabase, Stripe Elements, XState" |
| Constraint section | (missing) | Lists 5 constraints including SOC 2 status, Plaid lock-in, deadline |
| Architecture | "Built a scalable, performant solution" | Names every component, explains 3 contested decisions |
| Trade-offs | (missing) | Names 2 decisions they would revisit |
| Metrics | "Improved performance significantly" | Before/after table with 4 numbers |
| Testimonial | "Great team, highly recommend" attributed to "Director, B2B SaaS" | Specific quote with full name, title, LinkedIn link |
| Read time | 3 min | 4 min |
| Trust signal | Reads like a brochure | Reads like a senior engineer wrote it |
The good version is roughly 30% longer and converts 3 to 5 times better in our and our partner agencies' funnel data. The buyer is willing to read more if every paragraph teaches them something.
How agencies operationalize case studies
Three things separate agencies that publish 12 case studies a year from those that publish 2:
- A standing template (the one above) so the engineer doing the write-up is not designing the document.
- A 30-minute interview slot built into every project close-out, with five fixed questions: what was the hardest decision, what did the client push back on, what would you do differently, what is the metric we are proudest of, who is the testimonial-worthy contact.
- A two-pass review: technical lead checks accuracy, founder or head of growth checks readability.
The agencies that operationalize this also tend to think harder about agency utilization rates and the pricing models that feed those rates, because case studies are the proof artifact behind both.
Where booked engineers fit into the case study model
A growing number of agencies run hybrid teams: staff engineers plus booked engineers from marketplaces like Cadence for spiky work. Our recommendation after watching partner agencies run this play: attribute the engagement to the agency, name the stack and the metrics as normal, and only mention the talent model if the buyer asks.
If you do reference it, be honest. "Two of our three engineers on this engagement were booked via Cadence at the Senior tier ($1,500/week)" is fine. Vague superlatives are not, and trigger the skepticism case studies should disarm.
Every engineer on Cadence is AI-native by default, vetted on Cursor, Claude Code, and Copilot fluency through a founder-led voice interview before they unlock bookings. The 27-hour median time to first commit across our 12,800-engineer pool is what makes the hybrid model survivable inside a four-to-six-week project window.
For agency owners: if you have a backlog of unwritten case studies because the engineer closest to the story is on a new project, the partner program lets you earn 10% recurring on every founder you refer, often an easier monetization of past relationships than chasing the writeup.
What to do this week
Pick one engagement you closed in the last 90 days. Block 45 minutes on your calendar. Open the template. Fill in the seven sections, including the trade-off section, including the real metrics, including a real testimonial request to the client. Publish it within 14 days while the project is still vivid.
If you do this once a month for a year, you have 12 case studies. Most agencies have 2. That gap is the moat.
If your case-study pipeline is stalled because your senior engineers are too booked on client work to write, the cleaner unblock is structural: route the writing to your strongest junior, or hire a writer-engineer hybrid on a weekly basis so the cost is predictable. The case studies are revenue infrastructure, not marketing fluff.
Quick recap: real case studies name the stack, expose the metrics, admit the trade-offs, and quote a real person. Agencies that ship this format consistently outconvert the brochure-style competition by 3 to 5x. The partner program at Cadence is the natural fit if you also want to monetize past relationships with founders who outgrew you.
For more on the operating model behind a steady case-study cadence, read our deeper take on managing multiple client projects and the proposal patterns that close the kind of engagements worth writing up.
FAQ
How long should a dev agency case study be?
Aim for 800 to 1,200 words. Shorter reads as thin; longer loses the buyer. The sweet spot is roughly 4 minutes of reading time, which is what most technical buyers will give you on first contact.
What is the single most important section of a dev agency case study?
The metrics table with before-and-after numbers. Buyers scan the headline, then jump straight to the metrics. If the numbers are vague or missing, the rest of the document does not get read.
Do we need client permission to publish a case study?
Yes, every time. The standard pattern is to include "the agency may reference this engagement in marketing materials, subject to anonymization on request" in the SOW. Send the draft to the client before publishing and accept any redactions they ask for, including company name swaps.
Can we publish case studies without naming the client?
Yes. Use a pattern like "a Series B logistics SaaS in the EU, 40 engineers." The trade-off is roughly 30% less conversion impact than a named case study, but it is far better than no case study at all, and many NDAs require it.
How often should an agency publish new case studies?
One per month is the realistic target for a 5 to 20 person shop. Build the 30-minute close-out interview into every project so the raw material is captured while the work is fresh, then batch the writing.
Should we include the project budget in a case study?
Usually no. Include the budget envelope as a constraint ("six-figure budget, six-week deadline") but not the exact dollar amount, because it anchors future client negotiations against you. The exception is productized fixed-scope work where the price is already public.