Not always. The base build connects with an API key or personal access token, which Claude accepts on a custom connector as a beta for some organizations. A listing in the Claude directory needs OAuth 2.0 for services that sign users in, and ChatGPT can’t use API keys, so both need OAuth sign-in, the $1,000 add-on.

Will my connector be approved in the directories?

That decision belongs to each directory. You get the submission packet; approval is not guaranteed.

Who has built this before?

Simon built and runs the MCP server for Workspace369, his own production SaaS.

What if my API doesn’t have the endpoints a tool needs?

New API endpoints are outside the fixed scope. They can be quoted separately in writing.

Does the OAuth add-on make delivery longer?

Nothing when bought together (10 business days covers both). Added later, it is its own 5 business days from the OAuth details arriving.

Who submits to the directories?

You submit. App369 hands over the packet and answers your questions on it.

Do I need a call before I pay?

No. The scope, price and delivery time are on this page, and everything happens in writing. If you want to talk live, calls cost $100 per 15 minutes, paid upfront.

Who owns what you deliver?

You do. The code, videos and files delivered under this offer belong to you once paid.

Fixed-price offerAn MCP server for your SaaS, so it works inside Claude and ChatGPT

Customers are starting to ask whether your product works with their AI assistant. An MCP server is how it does: Claude and ChatGPT call your product’s actions as tools. This one is built over the REST API you already have, deployed to your own cloud account, and ready for directory submission.

Pay $2,500 & start Add OAuth sign-in (+$1,000)

Full refund if Simon can’t take it on once he sees your project, or if you cancel before work starts.

Check fit by email

Simon does the work himself
5.0 from 127 Fiverr reviews, checked Oct 30, 2026
Paid to App369 LLC through Stripe. Receipt by email, invoice with your company name on request.

$2,500 fixed price, 10 business days after your API docs and a test key arrive. OAuth sign-in, needed for ChatGPT, is a $1,000 add-on.

Price checked October 25, 2026.

No call needed. Ask a question first by email at contact@app369.com or with the contact form; we reply by email, usually within one business day.

MCP Connector for your SaaS

Make your product work inside Claude, and in ChatGPT with OAuth sign-in: an MCP server built over the REST API you already have.

$2,500

fixed price, OAuth sign-in +$1,000

You get

An MCP server exposing up to 8 tools over your existing, documented REST API
API-key or personal-access-token auth
Deployed to your own cloud account (Cloud Run, Workers or Vercel)
Tested in Claude. ChatGPT can’t use API keys, so it needs the OAuth sign-in add-on
A README plus a directory-submission packet: listing copy, example prompts and privacy notes

Add-on

OAuth sign-in, +$1,000 (needed for ChatGPT and a Claude directory listing), tested in Claude and ChatGPT

Not included

New API endpoints
Any guarantee of directory approval; that is up to each directory

Delivery

10 business days after your API docs and a test key arrive.

Simon built and runs the MCP server for Workspace369.

Pay $2,500 & start Add OAuth sign-in (+$1,000)

Full refund if Simon can’t take it on once he sees your project, or if you cancel before work starts.

After you pay

Simon emails you within one business day to confirm and send the access checklist. You can also send it straight away to contact@app369.com. What the work needs:

MCP Connector for your SaaS

Your REST API documentation
A test API key or personal access token for a test account
Which cloud you want it deployed to: Cloud Run, Cloudflare Workers or Vercel

Delivery takes 10 business days after your API docs and a test key arrive.

MCP Connector: OAuth sign-in add-on

Your OAuth provider or authorization server details
A test account that can sign in

OAuth sign-in is added to your MCP Connector build.

Full refund if Simon can’t take it on once he sees your project, or if you cancel before work starts.

Not sure it fits? See who it fits, or email a question about this offer; we reply by email, usually within one business day.

This fits when

You have a documented REST API with API keys or personal access tokens
Customers ask to use your product from Claude or ChatGPT
You want a listing in the Claude or ChatGPT connector directories
Your team has no time to learn the Model Context Protocol

Errors this fixes

Each page explains the error from the vendor’s own docs, with what to try first.

How it works

Pick the tools
Up to 8 actions from your API, chosen with you in writing: the ones customers would ask an assistant to do.
Build over your API
The MCP server calls your existing endpoints with API-key or token auth. No new endpoints are needed in your backend.
Deploy to your cloud
Deployed to your own Cloud Run, Cloudflare Workers or Vercel account, so you own and control it.
Test and hand over
Tested in Claude, with a README and a directory-submission packet: listing copy, example prompts and privacy notes. With the OAuth add-on it is tested in ChatGPT too.

What the tool list looks like

Step 1 of this offer, shown for the open-source SaaS MCP Connector, which Simon built over a small in-memory projects-and-tasks backend. Every tool works only inside the workspace its access token belongs to. A real build picks up to 8 tools from your API with you, in writing.

Tool	Kind	What it does	Safeguard
list_projects	Read	Lists the projects in your workspace	Marked read-only for the AI client
list_tasks	Read	Lists tasks, filtered by project, status or assignee	Marked read-only; returns 1 to 50 at a time
get_task	Read	Gets one task by its ID	Marked read-only for the AI client
search	Read	Searches project and task titles	Marked read-only for the AI client
create_task	Write	Creates a task in a project	Does nothing without an explicit confirm step; off in read-only mode
update_task_status	Write	Moves a task to to-do, in progress or done	Does nothing without an explicit confirm step; off in read-only mode

list_projects
Kind
Read
What it does
Lists the projects in your workspace
Safeguard
Marked read-only for the AI client
list_tasks
Kind
Read
What it does
Lists tasks, filtered by project, status or assignee
Safeguard
Marked read-only; returns 1 to 50 at a time
get_task
Kind
Read
What it does
Gets one task by its ID
Safeguard
Marked read-only for the AI client
search
Kind
Read
What it does
Searches project and task titles
Safeguard
Marked read-only for the AI client
create_task
Kind
Write
What it does
Creates a task in a project
Safeguard
Does nothing without an explicit confirm step; off in read-only mode
update_task_status
Kind
Write
What it does
Moves a task to to-do, in progress or done
Safeguard
Does nothing without an explicit confirm step; off in read-only mode

Sample only: an open-source demo over an in-memory test backend, not a client’s product. The tools and safeguards are taken from its README and code (checked October 23, 2026).

See the code on GitHub

Built before

Work Simon has shipped that uses the same kind of build. Every project links to something you can check.

2023–nowOur own product

Workspace369

SaaS, iOS & web

An all-in-one workspace for service businesses: CRM, proposals, invoicing and payments, scheduling and a shared email, SMS and voice inbox. Designed, built and run by App369.

Flutter app on iOS and the web, live on the App Store
Firebase backend split into 20+ Cloud Functions codebases
Stripe billing, Twilio voice and SMS, inbound email security

FlutterFirebaseTypeScriptStripeTwilio

Case study App Store

2026Open source by Simon Dziak

SaaS MCP Connector

AI integration

An MCP server that lets Claude use a SaaS API safely: every call is scoped to one user's workspace, writes need explicit confirmation, and the HTTP transport is rate limited.

TypeScriptMCPClaude

Case study GitHub

Questions before you pay

Do I need OAuth?: Not always. The base build connects with an API key or personal access token, which Claude accepts on a custom connector as a beta for some organizations. A listing in the Claude directory needs OAuth 2.0 for services that sign users in, and ChatGPT can’t use API keys, so both need OAuth sign-in, the $1,000 add-on.
Will my connector be approved in the directories?: That decision belongs to each directory. You get the submission packet; approval is not guaranteed.
Who has built this before?: Simon built and runs the MCP server for Workspace369, his own production SaaS.
What if my API doesn’t have the endpoints a tool needs?: New API endpoints are outside the fixed scope. They can be quoted separately in writing.
Does the OAuth add-on make delivery longer?: Nothing when bought together (10 business days covers both). Added later, it is its own 5 business days from the OAuth details arriving.
Who submits to the directories?: You submit. App369 hands over the packet and answers your questions on it.
Do I need a call before I pay?: No. The scope, price and delivery time are on this page, and everything happens in writing. If you want to talk live, calls cost $100 per 15 minutes, paid upfront.
Who owns what you deliver?: You do. The code, videos and files delivered under this offer belong to you once paid.

Fiverr reviews / 95 on app work

What buyers said about working with Simon

Read 126 of the 127 reviews

“szymondziak is a very competent developer. Communication was perfect. Will definitely recommend. Thanks for the great job szymondziak”
A buyer in Germany, June 2021. App development on Fiverr
“Very good work on the design. Looking forward to working with Szymon on the app development! Highly recommend!”
Eric, United States, June 2021. App design on Fiverr
“Szymon explained to me in detail the steps of the project. I appreciate his honesty and patience in explaining his service to someone like me who does not understand most technical lingo. I highly recommend his service!”
A buyer in the United States, May 2021. App development on Fiverr

Read the whole story

Sixteen five-star reviews from one buyer: mobile apps, app design and a Shopify store (Mark, United States)
A large custom app build, delivered on the back end and the front end (A buyer in the United States)

Ready to start?

Pay online and send what the work needs by replying to the Stripe receipt. Simon, who builds and runs the SaaS Workspace369, does the work himself.

Pay $2,500 & start Add OAuth sign-in (+$1,000)

Full refund if Simon can’t take it on once he sees your project, or if you cancel before work starts.

Related fixed-price offers

Fixed scope, fixed price, paid upfront. The work happens in writing; no call needed.

Looking for something else? See all fixed-price offers

Fixed-price offerAn MCP server for your SaaS, so it works inside Claude and ChatGPT

MCP Connector for your SaaS

You get

Add-on

Not included

Delivery

After you pay

This fits when

Errors this fixes

How it works

Pick the tools

Build over your API

Deploy to your cloud

Test and hand over

What the tool list looks like

Built before

Workspace369

SaaS MCP Connector

Questions before you pay

What buyers said about working with Simon

Read the whole story

Ready to start?

Further reading

Related fixed-price offers