Series and Numbering

Invoice numbering must comply with Spanish tax requirements. Frihet allows you to create custom series with flexible patterns so your invoices are numbered automatically, with independent counters per series.

What is a Series

A series is a group of invoices with its own numbering pattern and independent counter. They are useful when you need to separate business lines, branches, or billing types under the same NIF.

Example: a freelancer with two activities:

• FRI Series for their SaaS: FRI20260001, FRI20260002, etc.
• BRT Series for consulting: BRT20260001, BRT20260002, etc.

Each series has its own counter that advances independently.

How Numbering Works Without Series

If you do not configure series, Frihet uses a single global pattern with a single counter. This is the default behavior for new accounts:

1. Go to Settings > Invoicing
2. In the numbering section, define your pattern (e.g.: F{YEAR}{SEQ4})
3. Each invoice receives the next sequential number

For most freelancers with a single activity, this is sufficient.

Accessing Series Configuration

1. Go to Settings > Invoicing
2. Scroll down to the Invoice Series section
3. You will see your configured series (if any)

Creating a Series

First Time

When you add your first series, Frihet automatically migrates your current configuration:

1. Click on Add series
2. Frihet creates a "Default" series with your current pattern and counter
3. You can rename it and add more series

This migration is transparent: your existing invoices are not affected.

Adding More Series

1. Click on Add series
2. Complete the fields:
   • ID — Short and unique identifier (e.g.: fri, brt, consulting). Cannot be changed later.
   • Name — Descriptive name (e.g.: "Frihet SaaS", "BRTHLS Consulting")
   • Pattern — Numbering formula (e.g.: FRI{YEAR}{SEQ4})
3. The counter starts at 1 automatically

You can have up to 10 series.

Default Series

Exactly one series must be the default. It is the one pre-selected when creating a new invoice.

To change the default series, click on Set as default on the desired series.

Pattern Variables

The pattern uses dynamic variables that are automatically replaced:

Variable	Description	Example
{YEAR}	Current year with 4 digits	2026, 2027
{MONTH}	Month with 2 digits (01-12)	01, 02, ..., 12
{SEQ3}	Sequence of 3 digits (001, 002...)	001, 002, 999
{SEQ4}	Sequence of 4 digits (0001, 0002...)	0001, 0002, 9999
{SEQ5}	Sequence of 5 digits (00001, 00002...)	00001, 00002, 99999

The series prefix (FRI, BRT, F, etc.) is written directly into the pattern; it is not a separate variable.

Pattern Examples

With series prefix (recommended for multi-activity):

FRI{YEAR}{SEQ4}

Result: FRI20260001, FRI20260002, ..., FRI20269999

Classic pattern with hyphens:

F-{YEAR}-{SEQ4}

Result: F-2026-0001, F-2026-0002, ..., F-2026-9999

With month (to distinguish by period):

F-{YEAR}{MONTH}-{SEQ3}

Result: F-202601-001, F-202602-001, ...

Minimalist (sequence only):

{SEQ4}

Result: 0001, 0002, ...

With slash separator:

F/{YEAR}/{SEQ3}

Result: F/2026/001, F/2026/002, ...

Selecting a Series When Creating an Invoice

If you have more than one series configured, when creating an invoice you will see a series selector:

1. Open the new invoice form
2. In the dates section, select the desired series
3. The number will be automatically assigned according to the pattern and counter of that series

If you only have one series (or do not use series), no selector appears, and numbering works automatically.

Annual Auto-reset

When the year changes, the counter for each series automatically resets to 1 (if you have the annual reset policy activated).

Example:

• December 31, 2025: Last invoice FRI20250523
• January 1, 2026: First invoice FRI20260001

This policy is configured in Settings > Invoicing > Reset Policy. The options are:

• Annual (recommended): The counter resets every January 1st
• Never: The counter continues indefinitely

Editing a Series

You can edit the name and pattern of an existing series directly in the series section.

Important: Changes affect future invoices, NOT those already generated. The counter continues from where it was.

Example:

• You generated invoices FRI20260001 to FRI20260050 with the old pattern
• You change the pattern to FRIHET-{YEAR}-{SEQ4}
• The next invoice will be FRIHET-2026-0051 (the counter continues)

Deleting a Series

1. Click the delete button on the series
2. Confirm deletion

Existing invoices that used that series are not affected (they keep their number).

If you delete the default series, the first remaining series automatically becomes the default.

Changing the Counter

Each series shows the next number to be assigned. You can manually adjust this number if you need to continue numbering from another system.

Example:

• You migrate from Excel where you were on invoice 500
• You adjust the counter to 501
• The next invoice in that series will start at 501

Changing an Existing Invoice's Series

Once the invoice is issued, you CANNOT change its number or series (tax requirement). The number is immutable.

If you need to use a different series:

1. Create a new invoice with the correct series
2. Cancel or correct the original invoice if necessary

Common Use Cases

Freelancer with Multiple Activities

Separate income by line of business:

Series: Consulting
Pattern: CON{YEAR}{SEQ4}
Result: CON20260001

Series: Training
Pattern: FORM{YEAR}{SEQ4}
Result: FORM20260001

Company with Branches

One series per location:

Series: Madrid Invoices
Pattern: FM-{YEAR}-{SEQ4}
Result: FM-2026-0001

Series: Barcelona Invoices
Pattern: FB-{YEAR}-{SEQ4}
Result: FB-2026-0001

Different Client Types

Series: National Clients
Pattern: F-{YEAR}-{SEQ4}
Result: F-2026-0001

Series: International Clients
Pattern: FI-{YEAR}-{SEQ3}
Result: FI-2026-001

Migration from Another System

If you come from Excel, another ERP, or manual invoicing:

1. Create a series with the pattern you were using
2. Adjust the counter to the next number you need
3. New invoices continue numbering without gaps

Tax Requirements

Invoice numbering in Spain must be:

• Sequential (without gaps)
• Unique (no repeating numbers)
• Have clear identification (series + number)
• Be in chronological order (no backdating)

Frihet guarantees this automatically through an atomic counter on the server. Numbering is generated centrally to prevent duplicates or gaps, even if multiple people create invoices simultaneously. It is not possible to manually create an out-of-sequence number.

When using series, each series maintains its own sequential order independently. This complies with RD 1619/2012, which allows for distinct series as long as each one is sequential.

This gap-free numbering is also a requirement of RD 1007/2023 (VeriFactu) and is applied transparently.

Custom Branding per Series

Each series can have its own visual branding, independent of your account's global branding. This allows invoices from different business lines to have distinct visual identities.

Configuring Series Branding

1. Go to Settings > Invoicing > Invoice Series
2. In the series you want to customize, click on Customize branding
3. Configure the available fields:
   • Series logo — Shown in the PDF instead of the global logo
   • Trade name — Name of the business line (e.g.: "Frihet" vs "BRTHLS Consulting")
   • Accent color — Color for titles and table headers in the PDF
   • Invoice footer — Custom text at the bottom of the page

How Priority Works

When generating a PDF, Frihet resolves branding in this order:

1. If the invoice belongs to a series with its own branding → use the series branding
2. If the series does not have branding (or does not have that field) → use your account's global branding

This means you can customize only the logo for a series and keep the global color and footer.

Use Cases

Freelancer with two brands:

• FRI Series: Frihet logo, black color, footer "Frihet — Management Software"
• BRT Series: BRTHLS logo, gray color, footer "BRTHLS Consulting"

Same brand, different footers:

• National Series: footer with Spanish bank account
• International Series: footer with IBAN + SWIFT account

Visual Indicator

Series with custom branding show an "Own Branding" label in the configuration, allowing you to quickly identify which ones have active overrides.

Registry Book

Invoices from all series are included in the Registry Book, accessible from the invoice list. The document number (with its series prefix) is automatically reflected in the corresponding column.

To export the Registry Book as CSV, go to Invoices and use the Registry Book option.

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