Backblaze B2 Cloud Storage API
★ Only Publicly Available OpenAPI DocumentStorageObject Storagebasic24 EndpointsREST
For Agents
Upload, download, and manage objects in Backblaze B2 cloud storage. Create buckets, generate upload URLs, and handle multipart uploads for large files with application key-based access control.
Use for: I need to upload a backup file to Backblaze B2, I want to download a file from a B2 bucket by its ID, List all files in a specific bucket with a path prefix filter, Get a pre-authorized upload URL for a new bucket
Not supported: Does not handle CDN delivery, image transformations, or database storage — use for raw object storage and retrieval only.
Jentic publishes the only available OpenAPI specification for Backblaze B2 Cloud Storage API, keeping it validated and agent-ready. Store and retrieve objects in B2 cloud storage with 24 endpoints covering bucket management, file upload and download, application key administration, and large file multipart operations. Pricing runs at one-quarter the cost of major cloud providers with no egress fees for partner integrations and S3-compatible access.
Install Jentic One Beta
Connect the Backblaze B2 Cloud Storage API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Backblaze B2 Cloud Storage 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://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | 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 Backblaze B2 Cloud Storage API.
Upload files to B2 buckets using pre-authorized upload URLs with SHA-1 integrity verification
Download files by ID or by bucket-name-plus-path with byte-range support for partial retrieval
Split files over 100 MB into parts for parallel multipart upload with independent retry per part
Generate scoped application keys that restrict access to specific buckets, path prefixes, or operations
Configure bucket lifecycle rules to automatically transition or delete objects after a defined period
List file versions and hide specific versions to implement soft-delete without permanent removal
Use Cases
Patterns agents use Backblaze B2 Cloud Storage API for, with concrete tasks.
★ AI Agent Backup Automation
AI agents automate backup workflows by uploading snapshots, database dumps, and log archives to B2 storage through Jentic. The agent searches for the upload intent, receives the two-step schema (get upload URL, then upload file), and executes without browsing documentation. Application keys scoped to a single bucket ensure agents cannot access unrelated data. At $0.006/GB/month storage, B2 is cost-effective for high-volume backup retention.
Call /b2_get_upload_url for bucket 'daily-backups', then upload a 50 MB database dump using /b2_upload_file with SHA-1 verification
Large File Multipart Upload
Upload files larger than 100 MB using B2's multipart upload mechanism. Start a large file, obtain part upload URLs, upload each part independently (enabling parallel transfers), then finish the upload to assemble the final object. Failed parts can be retried individually without re-uploading the entire file. The API tracks unfinished large files for cleanup.
Start a large file with /b2_start_large_file, get part URLs with /b2_get_upload_part_url, upload 3 parts, then finalize with /b2_finish_large_file
Application Key Access Control
Generate scoped application keys that limit API access to specific buckets, file path prefixes, or operation sets. Distribute keys to different services or agents with least-privilege permissions. Keys can be created with expiration timestamps and restricted to read-only or write-only operations, preventing accidental data deletion from automated systems.
Create a read-only application key scoped to bucket 'public-assets' with prefix 'images/' using /b2_create_key
Cost-Effective Media Asset Storage
Store media files — images, videos, audio — at a fraction of the cost of major cloud providers. B2 charges $0.006/GB/month for storage with free egress through CDN partners (Cloudflare, Fastly). Files are accessed by ID for direct download or by bucket name and file path. Lifecycle rules auto-delete temporary assets after a configured retention period.
List all files with prefix 'videos/' in bucket 'media-assets' using /b2_list_file_names and retrieve metadata for the most recent upload with /b2_get_file_info
Key Endpoints
24 endpoints — jentic publishes the only available openapi specification for backblaze b2 cloud storage api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/b2_authorize_account
Authenticate and receive API URL and auth token
POST
/b2_get_upload_url
Get a URL for uploading files to a bucket
POST
/b2_upload_file
Upload a file to the bucket using the authorized URL
POST
/b2_download_file_by_id
Download a file by its unique file ID
POST
/b2_list_file_names
List file names in a bucket with optional prefix filter
POST
/b2_create_bucket
Create a new storage bucket
POST
/b2_create_key
Create a new application key with scoped permissions
POST
/b2_start_large_file
Begin a multipart upload for a large file
POST
/b2_authorize_account
Authenticate and receive API URL and auth token
POST
/b2_get_upload_url
Get a URL for uploading files to a bucket
POST
/b2_upload_file
Upload a file to the bucket using the authorized URL
POST
/b2_download_file_by_id
Download a file by its unique file ID
POST
/b2_list_file_names
List file names in a bucket with optional prefix filter
POST
/b2_create_bucket
Create a new storage bucket
POST
/b2_create_key
Create a new application key with scoped permissions
POST
/b2_start_large_file
Begin a multipart upload for a large file
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Backblaze B2 application key IDs and secrets are stored encrypted in the Jentic vault (MAXsystem). Agents receive pre-authorized tokens — raw keys never enter the agent's context.
Intent-based discovery
Agents search by intent (e.g., 'upload a file to cloud storage') and Jentic returns matching B2 operations with their input schemas, including the two-step upload flow (get URL then upload).
Time to first call
Direct B2 integration: 1-2 days for auth flow, upload URL management, and multipart handling. Through Jentic: under 1 hour — search, load schema, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Backblaze B2 Cloud Storage API through Jentic.
Why is there no official OpenAPI spec for Backblaze B2 Cloud Storage API?
Backblaze does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call Backblaze B2 Cloud Storage API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.
What authentication does the Backblaze B2 API use?
The B2 API uses HTTP Basic authentication for the initial /b2_authorize_account call, where the username is the application key ID and the password is the application key. This returns an authorization token and API URL used for all subsequent requests. Through Jentic, these credentials are stored encrypted in the MAXsystem vault.
Can I upload files larger than 100 MB with the B2 API?
Yes. Files under 100 MB use the single-call /b2_upload_file endpoint. Larger files use the multipart flow: /b2_start_large_file to initiate, /b2_get_upload_part_url for each part URL, upload parts individually (minimum 5 MB each except the last), then /b2_finish_large_file to assemble. Maximum file size is 10 TB.
How do I list files in a B2 bucket through Jentic?
Search Jentic for 'list files in a Backblaze bucket' to load the /b2_list_file_names operation schema. Pass the bucketId and optional prefix/delimiter parameters to filter results. The endpoint returns up to 10,000 files per call with a nextFileName cursor for pagination. Install with pip install jentic.
What are the rate limits for the Backblaze B2 API?
B2 allows unlimited API calls for most read operations. Write operations are limited to approximately 100 calls per second per account. The /b2_authorize_account endpoint is limited to prevent brute-force attacks. The API returns HTTP 429 or 503 with a Retry-After header when limits are hit.
How does B2 pricing compare to other cloud storage providers?
B2 storage costs $0.006/GB/month — roughly one-quarter the price of AWS S3 Standard. Download bandwidth is $0.01/GB, and egress through CDN partners (Cloudflare, Fastly, Bunny) is free. There are no minimum storage durations or per-request charges for standard operations.
GET STARTED