diff --git a/backlogger/__init__.py b/backlogger/__init__.py
new file mode 100644
index 0000000..91da91c
--- /dev/null
+++ b/backlogger/__init__.py
@@ -0,0 +1,20 @@
+"""
+The aim of this project is to extend pyerrors to be able to collect measurements from different projects and make them easily accessable to 
+the research group. The idea is to build a database, in which the researcher can easily search for measurements on a correlator basis,
+which may be reusable.
+As a standard to store the measurements, we will use the .json.gz format from pyerrors.
+This allows us to organize a library by files and exported dictionaries.
+Also, this is compressable, but is also human readable in uncompressed form.
+The project creates a database with a table to store the measurements, and a folder to store the .json.gz files and tracks the changes to the folder automatically using datalad.
+This way, we can harness the power of datalad as a backand, to reproducibly build our database.
+Projects, that are also datalad datasets can be linked to the backlog of correlators as subdatasets, such that, using datalad rerun function,
+it can be easily seen wehere the respective measurement came from and ho it may be reproduced.
+
+For now, we are interested in collecting primary IObservables only, as these are the most computationally expensive and time consuming to calculate.
+"""
+
+
+from .main import *
+from .input import *
+from .initialization import *
+from .io import *
diff --git a/backlogger/git_tools.py b/backlogger/git_tools.py
new file mode 100644
index 0000000..c003e29
--- /dev/null
+++ b/backlogger/git_tools.py
@@ -0,0 +1,31 @@
+import os
+import datalad.api as dl
+
+
+def move_submodule(repo_path, old_path, new_path):
+    """
+    Move a submodule to a new location.
+
+    Parameters
+    ----------
+
+    old_path: str
+        The old path of the module.
+    new_path: str
+        The new path of the module.
+    """
+
+    os.rename(repo_path + "/" + old_path, repo_path + "/" + new_path)
+    with open(repo_path + '/.gitmodules', 'r') as fp:
+        lines = fp.readlines()
+
+    for line in lines:
+        if line.startswith('\tpath'):
+            line = line.replace(old_path, new_path)
+            break
+        if line.startswith('[submodule "projects/tmp"]'):
+            line = line.replace(old_path, new_path)
+            break
+    with open(repo_path + '/.gitmodules', 'w') as fp:
+        fp.writelines(lines)
+    dl.save(repo_path, message="Move module from " + old_path + " to " + new_path, dataset=repo_path)
diff --git a/backlogger/initialization.py b/backlogger/initialization.py
new file mode 100644
index 0000000..590fed9
--- /dev/null
+++ b/backlogger/initialization.py
@@ -0,0 +1,46 @@
+import sqlite3
+import datalad.api as dl
+import os
+
+
+def _create_db(path):
+    """
+    Create the database file and the table.
+
+    """
+    conn = sqlite3.connect(path)
+    c = conn.cursor()
+    c.execute('''CREATE TABLE IF NOT EXISTS backlogs
+                 (id INTEGER PRIMARY KEY,
+                  name TEXT,
+                  ensemble TEXT,
+                  code TEXT,
+                  path TEXT,
+                  project TEXT,
+                  parameters TEXT,
+                  parameter_file TEXT,
+                  created_at TEXT,
+                  updated_at TEXT)''')
+    c.execute('''CREATE TABLE IF NOT EXISTS projects
+                 (id TEXT PRIMARY KEY,
+                  aliases TEXT,
+                  code TEXT,
+                  created_at TEXT,
+                  updated_at TEXT)''')
+    conn.commit()
+    conn.close()
+
+
+def create(path):
+    """
+    Create folder of backlogs.
+
+    """
+    dl.create(path)
+    _create_db(path + '/backlogger.db')
+    os.chmod(path + '/backlogger.db', 0o666)
+    os.makedirs(path + '/projects')
+    os.makedirs(path + '/projects/tmp')
+    os.makedirs(path + '/archive')
+    os.makedirs(path + '/import_scripts/template.py')
+    dl.save(path, dataset=path, message="Initialize backlogger directory.")
diff --git a/backlogger/input/__init__.py b/backlogger/input/__init__.py
new file mode 100644
index 0000000..f917e2a
--- /dev/null
+++ b/backlogger/input/__init__.py
@@ -0,0 +1,5 @@
+"""
+Import functions for different codes.
+"""
+
+from . import sfcf
diff --git a/backlogger/input/sfcf.py b/backlogger/input/sfcf.py
new file mode 100644
index 0000000..a8bb33d
--- /dev/null
+++ b/backlogger/input/sfcf.py
@@ -0,0 +1,195 @@
+import pyerrors as pe
+import datalad.api as dl
+
+
+def read_param(path, project, file_in_project):
+    """
+    Read the parameters from the sfcf file.
+
+    Parameters
+    ----------
+    file : str
+        The path to the sfcf file.
+
+    Returns
+    -------
+    dict
+        The parameters in the sfcf file.
+
+    """
+
+    file = path + "/projects/" + project + '/' + file_in_project
+    dl.get(file, dataset=path)
+    with open(file, 'r') as f:
+        lines = f.readlines()
+
+    params = {}
+    params['wf_offsets'] = []
+    params['wf_basis'] = []
+    params['wf_coeff'] = []
+    params['qr'] = {}
+    params['mrr'] = []
+    params['crr'] = []
+    params['qs'] = {}
+    params['mrs'] = []
+    params['crs'] = []
+
+    for line in lines:
+        if line.startswith('#'):
+            continue
+        if line.startswith('\n'):
+            continue
+        if line.startswith('wf_offsets'):
+            num_wf_offsets = line.split()[1]
+            for i in range(int(num_wf_offsets)):
+                params['wf_offsets'].append([float(x) for x in lines[lines.index(line) + i + 1].split("#")[0].split()])
+
+        if line.startswith('wf_basis'):
+            num_wf_basis = line.split()[1]
+            for i in range(int(num_wf_basis)):
+                params['wf_basis'].append([float(x) for x in lines[lines.index(line) + i + 1].split("#")[0].split()])
+
+        if line.startswith('wf_coeff'):
+            num_wf_coeff = line.split()[1]
+            for i in range(int(num_wf_coeff)):
+                params['wf_coeff'].append([float(x) for x in lines[lines.index(line) + i + 1].split("#")[0].split()])
+
+        if line.startswith('qr'):
+            num_qr = line.split()[1]
+            for i in range(int(num_qr)):
+                dat = lines[lines.index(line) + i + 1].split("#")[0].strip().split()[:-1]
+                params['qr'][dat[0]] = {}
+                params['qr'][dat[0]]['mass'] = float(dat[1])
+                params['qr'][dat[0]]['thetas'] = [float(x) for x in dat[2:5]]
+
+        if line.startswith('mrr'):
+            num_mrr = line.split()[1]
+            for i in range(int(num_mrr)):
+                params['mrr'].append(lines[lines.index(line) + i + 1].split("#")[0].strip())
+
+        if line.startswith('crr'):
+            num_crr = line.split()[1]
+            for i in range(int(num_crr)):
+                params['crr'].append(lines[lines.index(line) + i + 1].split("#")[0].strip())
+
+        if line.startswith('qs'):
+            num_qs = line.split()[1]
+            for i in range(int(num_qs)):
+                dat = lines[lines.index(line) + i + 1].split("#")[0].strip().split()[:-1]
+                params['qs'][dat[0]] = {}
+                params['qs'][dat[0]]['mass'] = float(dat[1])
+                params['qs'][dat[0]]['thetas'] = [float(x) for x in dat[2:5]]
+
+        if line.startswith('mrs'):
+            num_mrs = line.split()[1]
+            for i in range(int(num_mrs)):
+                params['mrs'].append(lines[lines.index(line) + i + 1].split("#")[0].strip())
+
+        if line.startswith('crs'):
+            num_crs = line.split()[1]
+            for i in range(int(num_crs)):
+                params['mrs'].append(lines[lines.index(line) + i + 1].split("#")[0].strip())
+
+    # catch standard cases
+    if params['wf_offsets'] == []:
+        params['wf_offsets'] = [[0, 0, 0]]
+
+    if params['wf_coeff'] == []:
+        params['wf_coeff'] = [[0, -1]]
+
+    return params
+
+
+def _map_params(params, spec_list):
+    """
+    Map the extracted parameters to the extracted data.
+
+    """
+
+    new_specs = {}
+    # quarks
+    quarks = spec_list[0].split(" ")
+
+    new_specs['quarks'] = (params['qr'][quarks[0]], params['qr'][quarks[1]])
+
+    # offset
+    new_specs['offset'] = (params['wf_offsets'][int(spec_list[1])])
+    # wf1
+    contribs = []
+    for i, coeff in enumerate(params['wf_coeff'][int(spec_list[2])]):
+        if not coeff == 0:
+            contrib = (coeff, params['wf_basis'][i])
+            contribs.append(contrib)
+    new_specs['wf1'] = contribs
+
+    if len(spec_list) == 4:
+        # wf2
+        contribs = []
+        for i, coeff in enumerate(params['wf_coeff'][int(spec_list[3])]):
+            if not coeff == 0:
+                contrib = (coeff, params['wf_basis'][i])
+                contribs.append(contrib)
+        new_specs['wf2'] = contribs
+    return new_specs
+
+
+def read_data(path, project, dir_in_project, prefix, param, version='1.0c', cfg_seperator='n', sep='/', **kwargs):
+    """
+    Extract the data from the sfcf file.
+
+    Returns
+    -------
+    dict
+        The data from the sfcf file.
+
+    """
+    names = kwargs.get('names', None)
+    corr_types = {
+        'f_A': 'bi',
+        'f_P': 'bi',
+        'g_A': 'bi',
+        'g_P': 'bi',
+        'f_1': 'bb',
+        'k_1': 'bb',
+    }
+    directory = path + "/projects/" + project + '/' + dir_in_project
+    dl.get(directory, dataset=path)
+    corr_type_list = []
+    for corr_name in param['crr']:
+        if corr_name not in corr_types:
+            raise ValueError('Correlator type not known.')
+        corr_type_list.append(corr_types[corr_name])
+
+    if not param['crr'] == []:
+        if names is not None:
+            data_crr = pe.input.sfcf.read_sfcf_multi(directory, prefix, param['crr'], param['mrr'], corr_type_list, range(len(param['wf_offsets'])),
+                                                     range(len(param['wf_basis'])), range(len(param['wf_basis'])), version, cfg_seperator, keyed_out=True, names=names)
+        else:
+            data_crr = pe.input.sfcf.read_sfcf_multi(directory, prefix, param['crr'], param['mrr'], corr_type_list, range(len(param['wf_offsets'])),
+                                                     range(len(param['wf_basis'])), range(len(param['wf_basis'])), version, cfg_seperator, keyed_out=True)
+
+    if not param['crs'] == []:
+        data_crs = pe.input.sfcf.read_sfcf_multi(directory, param['crs'])
+
+    data = {}
+    if not param['crr'] == []:
+        for key in data_crr.keys():
+            data[key] = data_crr[key]
+
+    if not param['crs'] == []:
+        for key in data_crs.keys():
+            data[key] = data_crs[key]
+
+    # sort data by correlator
+    sorted_data = {}
+    for key in data.keys():
+        key_parts = key.split(sep)
+        corr = key_parts[0]
+        if corr_types[corr] == 'bi':
+            specs = _map_params(param, key_parts[1:-1])
+        else:
+            specs = _map_params(param, key_parts[1:])
+        if corr not in sorted_data:
+            sorted_data[corr] = {}
+        sorted_data[corr][sep.join(key_parts[1:])] = data[key]
+    return sorted_data, specs
diff --git a/backlogger/io.py b/backlogger/io.py
new file mode 100644
index 0000000..ed01132
--- /dev/null
+++ b/backlogger/io.py
@@ -0,0 +1,46 @@
+from pyerrors.input import json as pj
+import os
+import datalad.api as dl
+import sqlite3
+
+
+def write_measurement(path, ensemble, measurement, uuid, code, parameters, parameter_file):
+    """
+    Write a measurement to the backlog.
+    If the file for the measurement already exists, update the measurement.
+
+    Parameters
+    ----------
+    path: str
+        The path to the backlogger folder.
+    ensemble: str
+        The ensemble of the measurement.
+    measurement: dict
+        Measurements to be captured in the backlogging system.
+    uuid: str
+        The uuid of the project.
+    """
+
+    for corr in measurement.keys():
+        file = path + "/archive/" + ensemble + "/" + corr + '/' + uuid + '.json.gz'
+        if not os.path.exists(path + "/archive/" + ensemble + "/" + corr):
+            os.makedirs(path + "/archive/" + ensemble + "/" + corr)
+        conn = sqlite3.connect(path + '/backlogger.db')
+        c = conn.cursor()
+        if os.path.exists(file):
+            dl.unlock(file, dataset=path)
+            known_meas = pj.load_json_dict(file)
+            for key in measurement[corr].keys():
+                known_meas[key] = measurement[corr][key]
+        else:
+            known_meas = measurement[corr]
+        pj.dump_dict_to_json(measurement[corr], file)
+        for subkey in measurement[corr].keys():
+            meas_path = file + "::" + subkey
+        if not os.path.exists(file):
+            c.execute("INSERT INTO backlogs (name, ensemble, code, path, project, parameters, parameter_file, created_at, updated_at) VALUES (?, ?, ?, ?, ?, ?, ?, datetime('now'), datetime('now'))", (corr, ensemble, code, meas_path, uuid, parameters, parameter_file))
+        else:
+            c.execute("UPDATE backlogs SET updated_at=datetime('now') WHERE path=?", (file,))
+        conn.commit()
+        conn.close()
+        dl.save([path + '/backlogger.db', file], message="Add measurement to database", dataset=path)
diff --git a/backlogger/main.py b/backlogger/main.py
new file mode 100644
index 0000000..2a8670e
--- /dev/null
+++ b/backlogger/main.py
@@ -0,0 +1,65 @@
+import sqlite3
+import datalad.api as dl
+import os
+from .git_tools import move_submodule
+
+
+def create_project(path, uuid, aliases=None, code=None):
+    """
+    Create a new project entry in the database.
+
+    Parameters
+    ----------
+    path: str
+        The path to the backlogger folder.
+    uuid: str
+        The uuid of the project.
+    name: str (optional)
+        Costum name for the project (e.g. 'cA determination on exponential clover').
+    code: str (optional)
+        The code that was used to create the measurements.
+    """
+    conn = sqlite3.connect(path + "/backlogger.db")
+    c = conn.cursor()
+    known_projects = c.execute("SELECT * FROM projects WHERE id=?", (uuid,))
+    if known_projects.fetchone():
+        raise ValueError("Project already imported, use update_project() instead.")
+
+    dl.unlock(path + "/backlogger.db", dataset=path)
+    c.execute("INSERT INTO projects (id, aliases, code, created_at, updated_at) VALUES (?, ?, ?, datetime('now'), datetime('now'))", (uuid, aliases, code))
+    conn.commit()
+    conn.close()
+    dl.save(path + "/backlogger.db", message="Added entry for project " + uuid + " to database", dataset=path)
+
+
+def import_project(url, path, aliases=None, code=None):
+    """
+    Parameters
+    ----------
+
+    url: str
+        The url of the project to import. This can be any url that datalad can handle.
+    path: str
+        The path to the backlogger folder.
+    name: str
+        Custom name of the project, alias of the project.
+    code: str
+        Code that was used to create the measurements.
+    """
+
+    # install in tmp to find uuid
+    tmp_path = path + '/projects/tmp'
+    dl.install(path=tmp_path, source=url, dataset=path)
+    with open(tmp_path + "/.datalad/config") as fp:
+        for line in fp:
+            if line.startswith("\tid"):
+                uuid = line.split()[2]
+                break
+
+    create_project(path, uuid, aliases, code)
+    move_submodule(path, 'projects/tmp', 'projects/' + uuid)
+    os.mkdir(path + '/projects/tmp')
+
+    os.mkdir(path + '/import_scripts/' + uuid)
+    dl.save(path, message="Import project from " + url, dataset=path)
+    return uuid