diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..5b46298
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,13 @@
+# top-most EditorConfig file
+root = true
+
+[Makefile]
+indent_style = tab
+
+# Unix-style newlines with a newline ending every file
+[{*.lua,*.md}]
+end_of_line = lf
+indent_style = space
+indent_size = 4
+insert_final_newline = true
+
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..b0d3987
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,41 @@
+name: Tests
+
+on: [push, pull_request]
+
+jobs:
+  unit_tests:
+    name: unit tests
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-22.04
+            rev: nightly/nvim-linux64.tar.gz
+          - os: ubuntu-22.04
+            rev: v0.9.0/nvim-linux64.tar.gz
+    steps:
+      - uses: actions/checkout@v3
+      - run: date +%F > todays-date
+      - name: Restore from todays cache
+        uses: actions/cache@v3
+        with:
+          path: _neovim
+          key: ${{ runner.os }}-${{ matrix.rev }}-${{ hashFiles('todays-date') }}
+
+      - name: Prepare
+        run: |
+          test -d _neovim || {
+            mkdir -p _neovim
+            curl -sL "https://github.com/neovim/neovim/releases/download/${{ matrix.rev }}" | tar xzf - --strip-components=1 -C "${PWD}/_neovim"
+          }
+      - name: Dependencies
+        run: |
+            git clone --depth 1 https://github.com/nvim-lua/plenary.nvim ~/.local/share/nvim/site/pack/vendor/start/plenary.nvim
+            ln -s "$(pwd)" ~/.local/share/nvim/site/pack/vendor/start
+      - name: Run tests
+        run: |
+          export PATH="${PWD}/_neovim/bin:${PATH}"
+          nvim --version
+          make test
+
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
new file mode 100644
index 0000000..a5f3ce3
--- /dev/null
+++ b/.github/workflows/format.yml
@@ -0,0 +1,26 @@
+name: Format
+
+on: [push, pull_request]
+
+jobs:
+    format:
+        name: Stylua
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - run: date +%W > weekly
+
+            - name: Restore cache
+              id: cache
+              uses: actions/cache@v2
+              with:
+                path: |
+                  ~/.cargo/bin
+                key: ${{ runner.os }}-cargo-${{ hashFiles('weekly') }}
+
+            - name: Install
+              if: steps.cache.outputs.cache-hit != 'true'
+              run: cargo install stylua
+
+            - name: Format
+              run: stylua --check lua/ --config-path=.stylua.toml
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
new file mode 100644
index 0000000..46759d5
--- /dev/null
+++ b/.github/workflows/lint.yml
@@ -0,0 +1,18 @@
+name: Lint
+
+on: [push, pull_request]
+
+jobs:
+    lint:
+        name: Luacheck
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v2
+            - name: Setup
+              run: |
+                  sudo apt-get update
+                  sudo apt-get install luarocks
+                  sudo luarocks install luacheck
+
+            - name: Lint
+              run: luacheck lua/ --globals vim
diff --git a/.luarc.json b/.luarc.json
new file mode 100644
index 0000000..e1b9d70
--- /dev/null
+++ b/.luarc.json
@@ -0,0 +1,4 @@
+{
+    "$schema": "https://raw.githubusercontent.com/sumneko/vscode-lua/master/setting/schema.json",
+    "Lua.workspace.checkThirdParty": false
+}
\ No newline at end of file
diff --git a/.stylua.toml b/.stylua.toml
new file mode 100644
index 0000000..0b2e146
--- /dev/null
+++ b/.stylua.toml
@@ -0,0 +1,5 @@
+column_width = 80
+line_endings = "Unix"
+indent_type = "Spaces"
+indent_width = 4
+quote_style = "AutoPreferDouble"
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..3011a8a
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2023-2024 marlin.nvim
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..e5e9c43
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,5 @@
+.PHONY: test
+
+test:
+	nvim --headless --noplugin -u scripts/test/minimal.vim \
+		-c "PlenaryBustedDirectory lua/marlin/test/ {minimal_init = 'scripts/tests/minimal.vim'}"
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..2f057f6
--- /dev/null
+++ b/README.md
@@ -0,0 +1,130 @@
+# marlin.nvim
+##### Smooth sailing between buffers
+
+Persistent and extensible jumps across project buffers with ease.
+
+### Setup
+
+Example using the lazy plugin manager
+
+```lua
+{
+    "desdic/marlin.nvim",
+    opts = {},
+    config = function(_, opts)
+        local marlin = require("marlin")
+        marlin.setup(opts)
+        local keymap = vim.keymap.set
+
+        keymap("n", "<Leader>fa", function() marlin.add_file() end, {  desc = "add file" })
+        keymap("n", "<Leader>fd", function() marlin.remove_file() end, {  desc = "remove file" })
+
+        for index = 1,4 do
+            keymap("n", "<Leader>"..index, function() marlin.open_index(index) end, {  desc = "goto "..index })
+        end
+    end
+}
+```
+
+### Default configuration
+
+```lua
+local default = {
+    patterns = { ".git", ".svn" }, -- look for root of project
+    datafile = vim.fn.stdpath("data") .. "/marlin.json", -- location of data file
+    open_callback = function(bufnr, opts) -- default way to change to indexed buffer
+        vim.api.nvim_set_current_buf(bufnr)
+    end,
+}
+```
+
+### Easy integration with most status lines
+
+Example with [lualine](https://github.com/nvim-lualine/lualine.nvim)
+
+```lua
+return {
+    "nvim-lualine/lualine.nvim",
+    config = function()
+        local marlin = require("marlin")
+
+        local marlin_component = function()
+            local indexes = marlin.get_number_of_indexes()
+            if indexes == 0 then
+                return ""
+            end
+            local cur_index = marlin.get_index_number()
+
+            return " " .. cur_index .. "/" .. indexes
+        end
+
+        require("lualine").setup({
+            ...
+            sections = {
+                ...
+                lualine_c = { marlin_component },
+                ...
+            },
+        })
+    end
+```
+
+### Extending behaviour
+
+Default behaviour is to replace the current buffer with the indexes one with
+
+```lua
+    open_callback = function(bufnr)
+        vim.api.nvim_set_current_buf(bufnr)
+    end,
+```
+
+But its possible to change the open_call function to get the behaviour you want. If you want to open new buffers in a vsplit you can
+
+```lua
+    open_callback = function(bufnr, _)
+        vim.cmd("vsplit")
+        vim.api.nvim_set_current_buf(bufnr)
+    end,
+```
+
+Or if want to add an options to open_index that switches to the buffer if already open in a split
+
+```lua
+    open_callback = function(bufnr, opts)
+        if opts.use_split then
+            local wins = vim.api.nvim_tabpage_list_wins(0)
+            for _, win in ipairs(wins) do
+                local winbufnr = vim.api.nvim_win_get_buf(win)
+
+                if winbufnr == bufnr then
+                    vim.api.nvim_set_current_win(win)
+                    return
+                end
+            end
+        end
+
+        vim.api.nvim_set_current_buf(bufnr)
+    end,
+```
+
+Choice is yours
+
+### TODO
+
+ - Function to align indexes with buffers
+ - Function delete all indexes
+ - Currently no GUI and there might not be one
+
+### Why yet another ..
+
+When I first saw harpoon I was immediately hooked but I missed a few key features.
+
+ - I use splits and wanted to have it jump to the buffer and not replace the current one.
+ - I wanted persistent jumps per project and not per directory.
+
+Like anyone else missing a feature I created a patch but it seems that many other did the same.
+
+### Credits
+
+Credit goes to [ThePrimeagen](https://github.com/ThePrimeagen/harpoon/) for the idea.
diff --git a/lua/marlin/datafile.lua b/lua/marlin/datafile.lua
new file mode 100644
index 0000000..b4442c5
--- /dev/null
+++ b/lua/marlin/datafile.lua
@@ -0,0 +1,35 @@
+local M = {}
+
+M.read_config = function(datafile)
+    if vim.fn.filereadable(datafile) ~= 0 then
+        local fd = io.open(datafile, "r")
+        if fd then
+            local content = fd:read("*a")
+            io.close(fd)
+            return vim.fn.json_decode(content)
+        end
+    end
+    return {}
+end
+
+M.save_data = function(datafile, project, localdata)
+    local data = M.read_config(datafile)
+    data[project] = localdata
+
+    -- If we have no more files we remove the project
+    if #data[project]["files"] == 0 then
+        data[project] = nil
+    end
+
+    local content = vim.fn.json_encode(data)
+    local fd = io.open(datafile, "w")
+    if not fd then
+        vim.notify("Unable to open " .. datafile .. " for write")
+        return
+    end
+
+    fd:write(content)
+    io.close(fd)
+end
+
+return M
diff --git a/lua/marlin/init.lua b/lua/marlin/init.lua
new file mode 100644
index 0000000..528d1ea
--- /dev/null
+++ b/lua/marlin/init.lua
@@ -0,0 +1,264 @@
+---@class marlin.commands
+---@field open_index fun(index: number, opts: any?): nil
+---@field remove_file fun(): nil
+---@field get_index_number fun(): number
+---@field get_number_of_indexes fun(): number
+---@field add_file fun(): nil
+---@field setup fun(opts: marlin.config): nil
+local M = {}
+
+---@class marlin.config
+---@field patterns? string[] patterns to detect root of project
+---@field datafile? string location of datafile
+---@field open_callback? fun(bufnr: number, opts: any?) function to set current buffer
+local default = {
+    patterns = { ".git", ".svn" },
+    datafile = vim.fn.stdpath("data") .. "/marlin.json",
+    open_callback = function(bufnr, opts)
+        vim.api.nvim_set_current_buf(bufnr)
+    end,
+}
+
+local datafile = require("marlin.datafile")
+local utils = require("marlin.utils")
+
+local get_cursor = function()
+    local cursor = vim.api.nvim_win_get_cursor(0)
+    return cursor[1] or 1, cursor[2] or 0
+end
+
+local update_location = function(marlin)
+    local cur_filename = utils.get_cur_filename()
+    if utils.is_empty(cur_filename) then
+        return
+    end
+
+    if not marlin.project_files["files"] then
+        marlin.project_files["files"] = {}
+    end
+
+    local row, col = get_cursor()
+    for idx, data in ipairs(marlin.get_indexes()) do
+        if data["filename"] == cur_filename then
+            marlin.project_files["files"][idx]["col"] = col
+            marlin.project_files["files"][idx]["row"] = row
+            break
+        end
+    end
+
+    vim.schedule(function()
+        datafile.save_data(
+            marlin.opts.datafile,
+            marlin.project_path,
+            marlin.project_files
+        )
+    end)
+end
+
+local swap = function(table, index1, index2)
+    table[index1], table[index2] = table[index2], table[index1]
+    return table
+end
+
+M.move_up = function()
+    local indexes = M.get_number_of_indexes()
+    if indexes < 2 then
+        return
+    end
+    local cur_index = M.get_index_number()
+
+    if cur_index == 1 then
+        swap(M.project_files["files"], cur_index, indexes)
+
+        return
+    end
+
+    swap(M.project_files["files"], cur_index, cur_index - 1)
+end
+
+M.move_down = function()
+    local indexes = M.get_number_of_indexes()
+    if indexes < 2 then
+        return
+    end
+
+    local cur_index = M.get_index_number()
+
+    if cur_index == indexes then
+        swap(M.project_files["files"], 1, cur_index)
+
+        return
+    end
+
+    swap(M.project_files["files"], cur_index, cur_index + 1)
+end
+
+---@param index number index to load
+---@param opts any? optional options to open_callback
+M.open_index = function(index, opts)
+    if not M.project_files["files"] then
+        return
+    end
+
+    opts = opts or {}
+
+    local idx = tonumber(index)
+    if idx > M.get_number_of_indexes() then
+        return
+    end
+
+    local cur_item = M.project_files["files"][idx]
+    local filename = cur_item.filename
+    local set_position = false
+
+    -- Check if file already in a buffer
+    local bufnr = vim.fn.bufnr(filename)
+    if bufnr == -1 then
+        -- else create a buffer for it
+        bufnr = vim.fn.bufnr(filename, true)
+        set_position = true
+    end
+
+    -- if the file is not loaded, load it and make it listed (visible)
+    if not vim.api.nvim_buf_is_loaded(bufnr) then
+        vim.fn.bufload(bufnr)
+        vim.api.nvim_set_option_value("buflisted", true, {
+            buf = bufnr,
+        })
+    end
+
+    M.opts.open_callback(bufnr, opts)
+
+    if set_position then
+        vim.api.nvim_win_set_cursor(0, {
+            cur_item.row or 1,
+            cur_item.col or 0,
+        })
+    end
+end
+
+M.remove_file = function()
+    local cur_filename = utils.get_cur_filename()
+    if utils.is_empty(cur_filename) or not M.project_files["files"] then
+        return
+    end
+
+    for idx, data in ipairs(M.project_files["files"]) do
+        if data["filename"] == cur_filename then
+            table.remove(M.project_files["files"], idx)
+
+            vim.schedule(function()
+                datafile.save_data(
+                    M.opts.datafile,
+                    M.project_path,
+                    M.project_files
+                )
+            end)
+
+            break
+        end
+    end
+end
+
+---@return number retuns current index and 0 if not found
+M.get_index_number = function()
+    local cur_filename = utils.get_cur_filename()
+    if utils.is_empty(cur_filename) then
+        return 0
+    end
+
+    if not M.project_files["files"] then
+        M.project_files["files"] = {}
+    end
+
+    for idx, data in ipairs(M.project_files["files"]) do
+        if data["filename"] == cur_filename then
+            return idx
+        end
+    end
+    return 0
+end
+
+---@return number returns number of indexes in current project
+M.get_number_of_indexes = function()
+    if not M.project_files["files"] then
+        return 0
+    end
+
+    return #M.project_files["files"]
+end
+
+M.get_indexes = function()
+    if M.get_number_of_indexes() == 0 then
+        return {}
+    end
+
+    return M.project_files["files"]
+end
+
+M.add_file = function()
+    local cur_filename = utils.get_cur_filename()
+    if utils.is_empty(cur_filename) then
+        return
+    end
+
+    if not M.project_files["files"] then
+        M.project_files["files"] = {}
+    end
+
+    local row, col = get_cursor()
+    for idx, data in ipairs(M.get_indexes()) do
+        if data["filename"] == cur_filename then
+            M.project_files["files"][idx]["col"] = col
+            M.project_files["files"][idx]["row"] = row
+            return
+        end
+    end
+
+    table.insert(M.project_files["files"], {
+        filename = cur_filename,
+        col = col,
+        row = row,
+    })
+
+    vim.schedule(function()
+        datafile.save_data(M.opts.datafile, M.project_path, M.project_files)
+    end)
+end
+
+local search_for_project_path = function(patterns)
+    for _, pattern in ipairs(patterns) do
+        local match = utils.get_project_path(pattern)
+        if match ~= nil then
+            return match
+        end
+    end
+    return nil
+end
+
+M.setup = function(opts)
+    M.opts = vim.tbl_deep_extend("force", default, opts or {})
+
+    -- Load project specific data
+    M.project_path = search_for_project_path(M.opts.patterns)
+
+    M.project_files = {}
+    local data = datafile.read_config(M.opts.datafile)
+    for key, value in pairs(data) do
+        if key == M.project_path then
+            M.project_files = value
+            break
+        end
+    end
+
+    local augroup = vim.api.nvim_create_augroup("marlin", {})
+    vim.api.nvim_create_autocmd({ "BufLeave", "VimLeavePre" }, {
+        group = augroup,
+        pattern = "*",
+        callback = function(_)
+            update_location(M)
+        end,
+    })
+end
+
+return M
diff --git a/lua/marlin/test/config_spec.lua b/lua/marlin/test/config_spec.lua
new file mode 100644
index 0000000..4933259
--- /dev/null
+++ b/lua/marlin/test/config_spec.lua
@@ -0,0 +1,12 @@
+describe("config", function()
+    local marlin = require("marlin")
+    local eq = assert.equals
+
+    local opts = {
+        patterns = { "Makefile" },
+    }
+
+    marlin.setup(opts)
+
+    eq(marlin.opts.patterns[1], "Makefile")
+end)
diff --git a/lua/marlin/utils.lua b/lua/marlin/utils.lua
new file mode 100644
index 0000000..488541e
--- /dev/null
+++ b/lua/marlin/utils.lua
@@ -0,0 +1,15 @@
+local M = {}
+
+M.get_cur_filename = function()
+    return vim.fn.expand("%:p")
+end
+
+M.get_project_path = function(patterns)
+    return vim.fs.dirname(vim.fs.find(patterns, { upward = true })[1])
+end
+
+M.is_empty = function(s)
+    return s == nil or s == ""
+end
+
+return M
diff --git a/scripts/test/minimal.vim b/scripts/test/minimal.vim
new file mode 100644
index 0000000..23618bf
--- /dev/null
+++ b/scripts/test/minimal.vim
@@ -0,0 +1,4 @@
+set noswapfile
+set rtp+=.
+set rtp+=../plenary.nvim
+runtime! plugin/plenary.vim