Clear Books API
Official vendor OpenAPI document · agent-readyFinanceAccountingoauth263 EndpointsREST
For Agents
Create and manage Clear Books invoices, bills, customers, suppliers, payments, journals, and bank feeds via 63 OAuth2-secured endpoints. Useful for UK accounting automation and bookkeeping sync.
Use for: I need to create a sales invoice for a UK customer, Push yesterday's bank statement into Clear Books, List all unpaid bills from a specific supplier, Allocate a customer payment to an outstanding invoice
Not supported: Does not handle payroll processing, HMRC Making Tax Digital submission, or card payment capture - use for Clear Books accounting records, sales and purchase documents, and bank feeds only.
The Clear Books API provides programmatic access to Clear Books, a UK-focused cloud accounting platform. It exposes the accounting domain as REST resources - businesses, account codes, bank accounts, customers, suppliers, sales documents (invoices and quotes), purchase documents (bills and expenses), payments, allocations, stock items, transactions, journals, VAT, and bank feeds. Authentication is OAuth 2.0 authorisation code with granular per-resource scopes, and the API supports paginated reads with X-Pagination-* response headers. It is designed for accountants, bookkeepers, and ISVs that need to sync trading activity, VAT data, or bank movements into Clear Books.
Install Jentic One Beta
Connect the Clear Books API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Clear Books API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fclearbooks.co.uk%2Fclearbooks" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fclearbooks.co.uk%2Fclearbooks" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Clear Books API.
Create and update invoices, quotes, bills, and expenses across sales and purchase document types
Manage customer and supplier records including bulk listing and per-record updates
Record payments and allocate them against sales or purchase documents
Post journal entries and read posted transactions for reconciliation
Push bank feeds and bank statements into Clear Books for matching
Read VAT information for return preparation
Maintain account codes, stock items, and bank accounts
Use Cases
Patterns agents use Clear Books API for, with concrete tasks.
★ Automated invoice creation from a sales pipeline
Service businesses that win deals in a CRM need invoices raised in Clear Books without rekeying. POST /accounting/sales/{salesType} with salesType=invoice creates the invoice in Clear Books from the won deal payload, and POST /accounting/customers ensures the contact exists first. This keeps invoice numbering sequential in the accounting system and removes the swivel-chair work between sales and finance.
When a deal is marked won in HubSpot, ensure the customer exists via GET/POST /accounting/customers, then POST /accounting/sales/invoice with the deal value to create the invoice
Bank feed and statement ingestion
Banks that are not natively supported by Clear Books bank feeds can be ingested through the API. POST to the bank feeds and bank statements endpoints (declared under /accounting/bankFeeds and /accounting/bankStatements scopes) pushes daily statement data so transactions are matched against invoices and bills. This lets businesses with niche bank accounts still benefit from Clear Books reconciliation without manual CSV uploads.
Each morning, fetch yesterday's transactions from the bank's API and POST them to the Clear Books bank statements endpoint for the matching bank account
VAT return preparation
Quarterly VAT returns require pulling sales, purchase, and VAT data from the accounting system. GET /accounting/sales/{salesType}, GET /accounting/purchases/{purchaseType}, and the VAT read endpoints supply the inputs. Running this on the first day of the new quarter lets the bookkeeper review the figures before submission.
On the first of each quarter, pull all sales and purchase documents for the previous three months and the VAT info to prepare the return spreadsheet
Customer and supplier directory sync
Businesses that maintain a master contact directory in another system push updates to Clear Books to keep customer and supplier addresses, payment terms, and contact details current. PATCH /accounting/customers/{customerId} and PATCH /accounting/suppliers/{supplierId} update individual records, while the GET endpoints support full directory diffs. This avoids the directory drift that causes invoices to be sent to old addresses.
Diff the master directory against GET /accounting/customers and PATCH each record where the billing address has changed
AI agent integration via Jentic
A bookkeeper's AI assistant uses Jentic to discover Clear Books endpoints by intent and execute them with OAuth tokens stored in your Jentic One instance. The agent can raise an invoice, allocate a payment, or pull VAT figures from natural-language requests, and the underlying authorisation code grant tokens are refreshed automatically. The single-token-per-user constraint is respected because Jentic manages the connection state for the agent.
Receive 'invoice ABC Ltd for 1500 GBP for consulting' from chat, search Jentic for Clear Books invoice creation, and execute POST /accounting/sales/invoice with the parsed values
Key Endpoints
63 endpoints — the clear books api provides programmatic access to clear books, a uk-focused cloud accounting platform.
METHOD
PATH
DESCRIPTION
POST
/accounting/sales/{salesType}
Create a sales document such as an invoice or quote
POST
/accounting/purchases/{purchaseType}
Create a purchase document such as a bill
POST
/accounting/customers
Create a customer record
POST
/accounting/suppliers
Create a supplier record
GET
/accounting/bankAccounts
List bank accounts
POST
/accounting/accountCodes
Create an account code
GET
/businesses
List all businesses for the current user
POST
/accounting/sales/{salesType}
Create a sales document such as an invoice or quote
POST
/accounting/purchases/{purchaseType}
Create a purchase document such as a bill
POST
/accounting/customers
Create a customer record
POST
/accounting/suppliers
Create a supplier record
GET
/accounting/bankAccounts
List bank accounts
POST
/accounting/accountCodes
Create an account code
GET
/businesses
List all businesses for the current user
Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring the Clear Books API by hand means running its OAuth2 authorization-code flow and refreshing tokens before any accounting call reaches api.clearbooks.co.uk. Through Jentic you install once, import Clear Books from the API Directory, store the credential once, and your agent calls it.
Permission scoping
Clear Books puts the sales and purchase type in the URL path (/accounting/sales/{salesType}), so a rule can pin your agent to one document type. You choose the operations it may call, so creating suppliers or reading bank accounts is not included unless you add it.
Credential isolation
Your Clear Books OAuth credential is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'create a sales invoice' or 'add a customer in Clear Books', and Jentic returns the matching operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Clear Books API through Jentic.
What authentication does the Clear Books API use?
Clear Books uses OAuth 2.0 with the Authorization Code grant only - no client credentials or implicit flow. Confidential clients are required, and PKCE is supported and recommended. Single-use refresh tokens are issued alongside access tokens. Through Jentic, the OAuth client and refresh token are stored in the encrypted vault and refreshed automatically.
What are the rate limits for the Clear Books API?
Applications making more than 5 requests per second for a sustained period may be throttled with HTTP 429 responses. Retries should use exponential backoff. Limits are not hard-coded and may change without notice, so your client should always honour 429 responses.
Can I create UK VAT-aware invoices through the Clear Books API?
Yes. POST /accounting/sales/{salesType} with salesType=invoice creates an invoice, and the VAT read endpoints expose the VAT settings used for return preparation. Combine with GET /accounting/customers to ensure the customer record exists before raising the invoice.
How do I push bank statements into Clear Books for reconciliation?
Use the bank statements endpoint under the accounting.bank_statements:write scope to push transactions for a given bank account. Combine with GET /accounting/bankAccounts to identify the target account ID. This is the standard pattern when a bank is not covered by Clear Books native feeds.
How do I raise a Clear Books invoice through Jentic?
Install the SDK with pip install jentic, search Jentic for 'create a clear books invoice', load the schema, and execute. Jentic manages the OAuth refresh-token rotation so the agent never holds the long-lived credential, and the single-active-token constraint per user is respected.
How does pagination work on the Clear Books API?
Paginated endpoints accept limit (max 200) and page parameters, and responses include X-Pagination-Limit, X-Pagination-Current-Page, X-Pagination-Total-Pages, and X-Pagination-Total-Count headers. Use the total-pages header to plan a full-table sync without making an extra count call.
Can I limit what my agent is allowed to do with the Clear Books API?
Yes. Because you run Jentic One yourself, your own rules decide exactly which Clear Books operations and credentials your agent may use. Clear Books puts the document type in the URL path, so you can pin the agent to a single type, for example allowing POST /accounting/sales/{salesType} for invoices while withholding supplier creation or bank account reads. Only the operations you explicitly grant are callable, so an agent set up to raise invoices cannot post journals or push bank statements unless you add those.
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