Series guide

Introduction

Series are numbering templates that generate unique, sequential identifiers for your documents. Most countries require sequential numbering for business documents like invoices to ensure traceability and compliance with tax regulations. Invopop’s Sequence service provides a reliable, scalable solution for generating sequential codes. Behind the scenes, we use a global transaction database to ensure that even under high-volume, distributed workloads, your series will generate numbers without skips or duplications.

What is a Series?

A series defines how sequential codes are formatted and generated. Each series includes:

Prefix: Text placed before the numeric portion (e.g., ES-, FR-)
Padding: Number of digits in the sequence (zeros are added to the left when necessary)
Start Number: The first number in the sequence
Suffix: Text appended after the numeric part (optional)
Code: Internal identifier for the series (optional)

For example, a series configured with:

Prefix: ES-
Padding: 5
Start number: 1
Code: INV

Will generate codes like:

INV-ES-00001
INV-ES-00002
INV-ES-00003

Creating a Series

You can create series through the Invopop Console or via the API. The Console provides a visual interface with a live preview of the generated codes.

Using the Console

Navigate to the Series section in the Invopop Console.
Click + Create Series or New Series.
Fill in the series configuration fields.
Review the live preview on the right side of the form.
Click Save to create the series.

Series Properties

Field	Description	API Property
Name	Human-readable label identifying the series.	`name`
Code (Optional)	Internal or business code used to categorize series.	`code`
Prefix (Optional)	Text placed before the numeric portion of the generated code.	`prefix`
Padding	Total number of digits in the numeric sequence. Zeros are added to the left when necessary.	`padding`
Start Number	The first number to be issued in the sequence.	`last_index`
Suffix (Optional)	Text appended after the numeric part.	`suffix`
Description (Optional)	Free text for internal documentation or identification.	`description`

Preview Panel

The Console displays a live preview of the resulting code based on your current field values. Use this to verify the format before saving.

INV-ES-00001

Using the API

Create a series via the API using a PUT request:

curl -X PUT "https://api.invopop.com/sequence/v1/series/{id}" \
  -H "Authorization: Bearer $INVOPOP_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Spanish Invoices",
    "code": "INV",
    "prefix": "ES-",
    "padding": 5,
    "last_index": 1,
    "suffix": "",
    "description": "Series for Spanish invoice numbering"
  }'

{
  "id": "835bb1ca-e7c4-41e6-9e88-464de54cc08e",
  "name": "Spanish Invoices",
  "code": "INV",
  "prefix": "ES-",
  "padding": 5,
  "last_index": 1,
  "suffix": "",
  "description": "Series for Spanish invoice numbering",
  "created_at": "2022-03-03T22:18:50Z",
  "updated_at": "2022-03-03T22:18:50Z"
}

Using Series in Workflows

The most common way to use series is through the Add Sequential Code step in your workflows. This step automatically generates the next number in the sequence and adds it to your document.

Dynamic vs. Static Series

When configuring the Add Sequential Code step, you can choose between:

Dynamic Series: Creates a new series automatically if one doesn’t exist with the specified name. This is useful when you want the workflow to handle series creation automatically.
Static Series: Uses an existing series that you’ve already created. Select the series from a dropdown of available series.

Adding a Sequential Code Step

In your workflow, click + Add step.
Search for or select Add Sequential Code.
Choose either Dynamic or Static series mode.
If using Dynamic, enter a name for the series (e.g., “Invoice”).
If using Static, select an existing series from the dropdown.
Configure additional options if needed (such as signing the document).

The Add Sequential Code step uses the sequence.enumerate provider. When using dynamic series, the step will create a new series with default settings (padding: 6, start: 1) if one doesn’t exist.

Using Series via API

You can also generate sequential codes directly via the API by creating entries in a series.

Creating a Series Entry

To generate the next code in a series, create an entry:

curl -X PUT "https://api.invopop.com/sequence/v1/series/{series_id}/entries/{entry_id}" \
  -H "Authorization: Bearer $INVOPOP_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "meta": {
      "invoice_id": "abc123",
      "customer": "Customer Name"
    }
  }'

{
  "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
  "series_id": "835bb1ca-e7c4-41e6-9e88-464de54cc08e",
  "code": "INV-ES-00001",
  "meta": {
    "invoice_id": "abc123",
    "customer": "Customer Name"
  },
  "previous_id": null,
  "sigs": [],
  "created_at": "2023-01-25T08:04:14.245Z",
  "updated_at": "2023-01-25T08:04:14.245Z"
}

The code field in the response contains the generated sequential code. You can then use this code in your document’s series field.

Fetching Series Information

Retrieve all series in your workspace:

curl -X GET "https://api.invopop.com/sequence/v1/series" \
  -H "Authorization: Bearer $INVOPOP_TOKEN"

Fetch a specific series by ID:

curl -X GET "https://api.invopop.com/sequence/v1/series/{series_id}" \
  -H "Authorization: Bearer $INVOPOP_TOKEN"

Best Practices

Naming Conventions

Use descriptive names that indicate the purpose (e.g., “Spanish Invoices”, “Credit Notes”, “Orders”).
Consider including country codes or business unit identifiers in the name for multi-country or multi-entity setups.

Prefixes and Suffixes

Use prefixes for country codes (e.g., ES-, FR-, US-) or business unit identifiers.
Use suffixes for year codes (e.g., -2024) when you need to reset numbering annually.
Keep prefixes and suffixes short to maintain readable codes.

Padding Considerations

Choose padding that accommodates your expected volume. For example:
- Padding of 3 supports up to 999 documents (001 to 999).
- Padding of 6 supports up to 999,999 documents (000001 to 999999).
Ensure padding is adequate for your invoicing volume to avoid running out of numbers.

Start Numbers

Start Number is typically 1 for new series.
If you’re continuing an existing series (e.g., migrating from another system), set the start number to the next number in your sequence.

Multiple Series

Create separate series for different document types or use cases:

Invoices: One series for standard invoices
Credit Notes: A separate series for credit notes
Orders: A series for purchase orders
Deliveries: A series for delivery notes

Some countries require specific series formats. For example, Portugal requires series names to follow specific formats with document type prefixes (e.g., FT for invoices, NC for credit notes).

Code and Description Fields

Code: Use for internal categorization or business logic. This field is optional and doesn’t appear in the generated sequential code.
Description: Use for internal documentation or notes about the series purpose. This field is optional and doesn’t affect code generation.

Examples

Example 1: Simple Invoice Series

A basic series for invoices with no prefix or suffix:

Name: “Standard Invoices”
Code: INV
Prefix: (empty)
Padding: 6
Start Number: 1
Suffix: (empty)

Generated codes: 000001, 000002, 000003, …

Example 2: Country-Specific Series

A series for Spanish invoices with country prefix:

Name: “Spanish Invoices”
Code: INV
Prefix: ES-
Padding: 5
Start Number: 1
Suffix: (empty)

Generated codes: INV-ES-00001, INV-ES-00002, INV-ES-00003, …

Example 3: Year-Based Series

A series that resets each year with a year suffix:

Name: “Annual Invoices”
Code: INV
Prefix: (empty)
Padding: 4
Start Number: 1
Suffix: -2024

Generated codes: 0001-2024, 0002-2024, 0003-2024, …

When using year-based suffixes, you’ll need to create a new series each year or manually update the suffix and reset the start number.

FAQ

Can I reuse a series for different document types?

While technically possible, it’s recommended to use separate series for different document types (invoices, credit notes, orders, etc.) to maintain clear separation and comply with country-specific requirements.

What happens if I reach the maximum number in a series?

If you reach the maximum number (e.g., 999999 with padding of 6), you’ll need to create a new series or increase the padding. Plan your padding based on expected volume to avoid this issue.

Can I skip numbers in a series?

No. The Sequence service guarantees sequential numbering without skips or duplications. Each entry receives the next number in sequence. If you need to skip numbers (e.g., for voided invoices), handle this in your application logic rather than in the series itself.

How do I continue an existing series from another system?

When creating a new series, set the Start Number to the next number in your existing sequence. For example, if your last invoice was INV-00100, create a new series with start number 101.

What's the difference between Code and the generated code?

The Code field is an optional internal identifier for the series (stored in the code property). The generated sequential code (returned in the code field of an entry) is the formatted string that includes prefix, padded number, and suffix (e.g., INV-ES-00001).

Can I modify a series after creating it?

You can update some series properties via the API, but be cautious as changes may affect existing entries. The last_index property tracks the current position in the sequence and should generally not be modified manually.

API Reference

Workflows Guide - Learn how to use series in workflow steps
PDF Invoice Guide - See series in action with PDF invoice generation
Series (Console) - Console-specific series documentation

Participate in our community

Ask and answer questions about series →

Set-up

Countries

GOBL

Apps

API

Features

Introduction

What is a Series?

Creating a Series

Using the Console

Series Properties

Preview Panel

Using the API

Using Series in Workflows

Dynamic vs. Static Series

Adding a Sequential Code Step

Using Series via API

Creating a Series Entry

Fetching Series Information

Best Practices

Naming Conventions

Prefixes and Suffixes

Padding Considerations

Start Numbers

Multiple Series

Code and Description Fields

Examples

Example 1: Simple Invoice Series

Example 2: Country-Specific Series

Example 3: Year-Based Series

FAQ

API Reference

Participate in our community

Set-up

Countries

GOBL

Apps

API

Features

​Introduction

​What is a Series?

​Creating a Series

​Using the Console

​Series Properties

​Preview Panel

​Using the API

​Using Series in Workflows

​Dynamic vs. Static Series

​Adding a Sequential Code Step

​Using Series via API

​Creating a Series Entry

​Fetching Series Information

​Best Practices

​Naming Conventions

​Prefixes and Suffixes

​Padding Considerations

​Start Numbers

​Multiple Series

​Code and Description Fields

​Examples

​Example 1: Simple Invoice Series

​Example 2: Country-Specific Series

​Example 3: Year-Based Series

​FAQ

​API Reference

​Related Guides

Participate in our community

Introduction

What is a Series?

Creating a Series

Using the Console

Series Properties

Preview Panel

Using the API

Using Series in Workflows

Dynamic vs. Static Series

Adding a Sequential Code Step

Using Series via API

Creating a Series Entry

Fetching Series Information

Best Practices

Naming Conventions

Prefixes and Suffixes

Padding Considerations

Start Numbers

Multiple Series

Code and Description Fields

Examples

Example 1: Simple Invoice Series

Example 2: Country-Specific Series

Example 3: Year-Based Series

FAQ

API Reference

Related Guides