Stack · Backend engineering

API delivery desk

Designs the endpoint, wires the auth and the payment, and reviews the shape before it is public and permanent.

Built for: The team shipping the first version of an API that other people will build against — and cannot quietly rename next month.

Install all 10 parts

The button opens the checkout, where the 5 servers and 5 skills are listed one by one. Every member is free, so the checkout lists them and asks for no card.

$0/mo
every member is free — 5 servers and 5 skills
$0
the free-tier version keeps 5 servers and 5 skills — and all 1 tool
$0
5 skills with no monthly cost
91.8k
tokens if every skill file is read in full — a skill loads its description first and the rest only when used
01 · Outcome

What your agent can do with this

The reason to buy a stack rather than five listings: each line below needs more than one member connected at the same time.

  1. 01

    Review a REST design against security, resilience and operational rules while it is still a document.

  2. 02

    Read the schema behind the endpoint on a read-only Postgres connection and keep the response honest about it.

  3. 03

    Wire OAuth 2.1 with PKCE and refresh, and a Stripe checkout, from the same desk that wrote the route.

  4. 04

    Deploy the service to Railway and read back what the platform says about it.

02 · Assembly

The assembly, part by part

What each part contributes, and why it was picked over the obvious alternative. Prices and permissions are read from the listings, so nothing here can disagree with the catalogue.

5 servers5 skills1 tool
RE01
Resend MCP server Email by gui-wf

Emails, domains and templates through the Resend API: every API grows a transactional mail obligation by the second week.

read/write split not recordedruns on your machine A v1.0.1 credential not declared · runs locally
Free
$0 of the monthly total
DA02

Read-only access to the data the endpoint returns, with row caps and statement timeouts, so design questions get real answers.

read/write split not recordedruns on your machine A v0.4.2 API key · runs locally
Free
$0 of the monthly total
GI03

The route, the spec and the review live in the same repository; this is the desk's way in and out of it.

read/write split not recordedruns on your machine A v2.2.5 · updated yesterday API key · runs locally
Free
$0 of the monthly total
OP04
Openai MCP server AI & Agents by @mzxrai

The OpenAI API as a plain dependency, for the endpoints that call a model and now need their own timeouts and costs.

1 readread-onlyruns on your machine A v0.1.1 credential not declared · runs locally
Free
$0 of the monthly total
RA05

Manages the Railway infrastructure the service runs on, so deploying is part of the same session rather than a different tool.

read/write split not recordedruns on your machine A v1.3.0 credential not declared · runs locally
Free
$0 of the monthly total
and the instructions that drive them A skill is a prompt file, not a server: it adds context and a procedure, never a tool or a permission of its own.
RE06
Review API Design Agent skill by psenger

Reviews the design while it is still cheap to change: security, resilience, pagination, errors, versioning — the list a public API is judged on later.

51.1k tokens when loaded in full write access not declared 21 files · CC-BY-4.0 v1.0.0 needs no server of its own
Free
no monthly cost
OA07
OAuth Agent skill by mcollina

Implements the authorisation-code-with-PKCE, client-credentials and refresh flows properly, which is where hand-written auth usually goes wrong.

1.9k tokens when loaded in full write access not declared 2 files · MIT needs no server of its own
Free
no monthly cost
ST08
Stripe Agent skill by sundial-org

The integration side of payments — payments, subscriptions, invoices and customers — kept to Stripe's own current patterns.

200 tokens when loaded in full write access not declared 1 file · CC0-1.0 needs no server of its own
Free
no monthly cost
UC09
UCP Checkout REST Agent skill by OrcaQubits

A worked checkout contract over REST, with idempotency and status transitions, for teams building the commerce half of the API.

1.1k tokens when loaded in full asks the agent to write 1 file · MIT needs no server of its own
Free
no monthly cost
ME10
Mem0 Agent skill by mem0ai

For the endpoint that has to remember a user between calls: a memory layer added deliberately, rather than a growing prompt.

37.5k tokens when loaded in full write access not declared 14 files · Apache-2.0 v3.1.0 needs no server of its own
Free
no monthly cost
03 · Cost

What it costs, and on what assumption

Every member is free, so the monthly figure is $0 whatever you do with the stack: nothing here is billed by the call, and only adding a paid member could change it.

PartWhat you are paying forMonthly, as quoted
Resend Free —
Database Postgres Free —
GitLab Free —
Openai Free —
Railway Free —
Skills
Review API Design Free · context cost only —
OAuth Free · context cost only —
Stripe Free · context cost only —
UCP Checkout REST Free · context cost only —
Mem0 Free · context cost only —
Everything above $0 of servers plus $0 of skills, the same in a quiet month and a busy one $0/mo

Subscriptions at their monthly plan price; one-off licences spread over 12 months.

The free-tier version$0/mo
What moves the bill
Flat every month$0 · 0 subscriptions
Carries a call allowancenothing
Paid oncenothing
Traffic assumed5k calls / month

Nothing in this stack carries a call allowance, so nothing here can run out before the month does. The bill is decided when you install it, not when you use it.

The spend cap is one figure for the whole account, set in your dashboard and checked when an order is placed. On the call path what stops a retry loop is the plan's call allowance and its rate limit, and a refused call is never billed.

04 · Setup

Setting it up, in order

The steps below come before the install lines: what to decide and scope before connecting anything, in the order it matters. The lines themselves follow, part by part, for the client you pick.

1
Read-only database first
Point Postgres at a replica before the first design session. An API design conversation that guesses at the schema produces a contract that does not survive the data.
2
No live Stripe key in the desk
The Stripe skill wires the integration in your code against a test key. No member of this stack needs a live secret key.
3
Set the Railway project
Scope the token to one project. This desk manages the service it built, not the rest of the estate.
4
Agree the words before the routes
Half of API review disagreements are two people using 'resource' to mean different things. Write the terms down before the first review.
Install, part by part10 parts of 10 in Claude Code

npx mcprush@latest stack add api-delivery writes all 5 servers into Claude Code’s config in one go — or run the lines below one by one. The 5 skills are not included — add them with lines 06–10.

Keys you’ll need
Database Postgres
POSTGRES_HOST — Database host
POSTGRES_USER — Database user (a read-only user is recommended)
POSTGRES_PASSWORD — Database password (or use POSTGRES_PASSWORD_FILE)
POSTGRES_DATABASE — Database name
GitLab
GITLAB_PERSONAL_ACCESS_TOKEN — GitLab personal access token for local stdio use
Openai
OPENAI_API_KEY — Your OpenAI API key
Railway
RAILWAY_API_TOKEN — Your Railway API token (railway.app/account/tokens)

Set them where you start Claude Code — export POSTGRES_HOST=… in your shell profile on macOS and Linux, setx POSTGRES_HOST "…" on Windows, then open a new terminal. Claude Code reads them at start; the config keeps only the names.

# 01 · Resend claude mcp add --scope user resend-mcp '--' npx -y mcp-resend # 02 · Database Postgres claude mcp add --scope user --env 'POSTGRES_HOST=${POSTGRES_HOST}' --env 'POSTGRES_USER=${POSTGRES_USER}' --env 'POSTGRES_PASSWORD=${POSTGRES_PASSWORD}' --env 'POSTGRES_DATABASE=${POSTGRES_DATABASE}' --transport stdio database-postgres-mcp '--' npx -y @database-mcp/postgres # 03 · GitLab claude mcp add --scope user --env 'GITLAB_PERSONAL_ACCESS_TOKEN=${GITLAB_PERSONAL_ACCESS_TOKEN}' --transport stdio zereight-gitlab-mcp '--' npx -y @zereight/mcp-gitlab # 04 · Openai claude mcp add --scope user --env 'OPENAI_API_KEY=${OPENAI_API_KEY}' --transport stdio openai-mcp '--' npx -y @mzxrai/mcp-openai # 05 · Railway claude mcp add --scope user --env 'RAILWAY_API_TOKEN=${RAILWAY_API_TOKEN}' --transport stdio railway-mcp '--' npx -y @jasontanswe/railway-mcp # 06 · Review API Design npx mcprush@latest skill add psenger/review-api-design # 07 · OAuth npx mcprush@latest skill add mcollina/oauth # 08 · Stripe npx mcprush@latest skill add sundial-org/stripe # 09 · UCP Checkout REST npx mcprush@latest skill add orcaqubits/ucp-checkout-rest # 10 · Mem0 npx mcprush@latest skill add mem0ai/mem0
Requirements and Windows tips
  • Node.js — the current LTS (24) is the safe choice (for npx).
  • Windows PowerShell says 'running scripts is disabled on this system'? Run Set-ExecutionPolicy -Scope CurrentUser RemoteSigned once, or type npx.cmd instead of npx (codex.cmd, gemini.cmd, grok.cmd likewise). PowerShell 7 needs neither.

Nothing is connected until you approve it in Claude Code. mcprush is not in the path and meters nothing here.

Before you start
  • 2 members want an API key, set in your own client’s config on your machine — this marketplace never holds it.
  • 3 members have not declared what credential they need — check each one’s own page before you start.
  • What this stack can write is not recorded — 4 members of 5 have no imported tool surface. Section 05 says what is known before you approve anything.
  • 5 members are connected straight from their own package or address — nothing in them goes through mcprush.
05 · Permissions

What the whole stack can reach

Installed together, these tool surfaces add up. It is the first thing a security reviewer asks for, so what has been counted — and what nobody has counted yet — is on the page rather than in a PDF.

—
tools that only read
Which tools read and which write is counted from the surface a publisher imports, and 4 members of 5 have no imported tool surface.
—
tools that can change something
Not recorded, and not estimated: a total added up from the members that have a surface would be read as the whole stack’s. The table below is what is known, member by member.
0
tools that reach the network
1 of the 1 never leave your machine — they belong to the local members.
Who grants the write accessnot recorded
MemberTool surfaceWrite tools
Database Postgres not imported not recorded
GitLab not imported not recorded
Railway not imported not recorded
Resend not imported not recorded
Reading the number

A stack's blast radius is the union of its members, not the worst of them. That union cannot be taken here, because 4 members of 5 have no imported tool surface — so the figure a review asks for is missing rather than low, and a member marked not imported is one nobody has counted rather than one that cannot write.

1 skill in this stack instructs the agent to write — UCP Checkout REST. A skill holds no permission of its own; it can only ask a server that already has the scope, and the approval gate still applies.

Tools in total1
Write sharenot recorded
Members that can writenot recorded
Surface imported1 of 5 members
06 · Swaps

Sensible swaps

A stack is a default, not a verdict. These are the substitutions the maintainer would make, and what each one costs or saves.

For an API that ships as functions rather than as a service, the Vercel server manages the same deploy from the same desk.

same money at 5k calls tool counts not recorded both grade A

Transactional mail is one interchangeable dependency; take whichever account you already have domains verified on, and the API code changes in one place.

same money at 5k calls tool counts not recorded both grade A
07 · Limits

Where this stack stops

Written by the maintainer, kept on the page rather than in a support thread.

  • It cannot approve its own design. The review skill produces findings; whether the API ships with them open is a person's call.

  • It cannot move money. The Stripe skill writes the checkout into your code; nothing in this stack reads or changes a live Stripe account.

  • It does not write your client SDKs. Generating and publishing packages is outside this stack.

08 · Maintenance

Who keeps this current

A stack has an owner: whoever keeps it re-checks the combination when a member changes, and the members themselves are published by the people named on each row.

Maintainer
mcprush
The marketplace’s own editors — keep 40 stacks here
Version
—
Not versioned — the curator edits in place
Scanned members
5 of 5
Servers in it that carry a scan grade for the release they serve.
Member trust score
94–100
Lowest to highest client score of its 5 scanned servers, out of 100.
Composition
5 + 5
5 servers, 5 skills
Nearby

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